Chapter IV: Part I: Marine Algae (1)

SEAWEED

When descends on the Atlantic
The gigantic
Storm-wind of the equinox,
Landward in his wrath he scourges
The toiling surges,
Laden with seaweed from the rocks;

From Bermuda's reefs; from edges
Of sunken ledges
In some far-off, bright Azore;
From Bahama and the dashing,
Silver-flashing
Surges of San Salvador;

* * * * *

Ever drifting, drifting, drifting
On the shifting
Currents of the restless main;
Till in sheltered coves, and reaches
Of sandy beaches,
All have found repose again.

LONGFELLOW.

I

BLUE-GREEN SEAWEEDS (CYANOPHYCEAE)

GRASS-GREEN SEAWEEDS (CHLOROPHYCEAE)

TABLE SHOWING THE CLASSIFICATION OF THE BLUE-GREEN SEAWEEDS DESCRIBED IN THIS CHAPTER

Class =ALGAE=

Subclass =Cyanophyceae= (/Blue-Green Seaweeds/)

Order =NOSTOCACEAE=

Genera Species

^Spirulina^
^Oscillaria^
^Calothrix^
^Lyngbya^ ^L. majuscula^
^L. ferruginea^

[pg049]

BLUE-GREEN SEAWEEDS

The minute algae, which form patches of purple color on rocks, slimy layers or spots on wharves, bluish-green slime on mud, emerald-green films on decaying algae, blue-green slime on brackish ditches, and so on, are various species of the subclass =Cyanophyceae=. The prevailing color of these plants is blue-green, but some are purple, brown, or pink. Some of them are gelatinous in texture and shapeless, others have more definite forms; but all are too small to classify without the aid of a powerful glass, and are not of special interest except to the botanist.

GENERA ^Oscillaria^ and ^Spirulina^

The genus ^Oscillaria^ is so named from an oscillating movement which these filamentous plants show when viewed under the microscope. They are very delicate blue-green threads occurring singly, or in loose or felt-like floating masses, or like slime or scum, on mud or woodwork. In ^Spirulina^ the filaments are spirally twisted like a corkscrew and also have a vibrating movement. /Spirulina/ is often found growing with /Oscillaria/, and forms purple patches on wharves.

GENUS ^Calothrix^

("/Beautiful hair/")

Filaments one tenth of an inch long, terminating in transparent hair-like points, occasionally branching. The plant grows in fine tufts or like a fringe on algae or in patches on rocks. Sometimes it forms a spongy layer, again a velvety stratum. The color varies in different species; it may be bright green, brownish-green, [pg050] or dark bluish-purple. The genus is very common, and the plants are often found on the bottoms of boats.

GENUS ^Lyngbya^

(/Named for Hans Christian Lyngbye, a Danish botanist/)

^L. majuscula^, mermaid's-hair. The filaments are curled or
crisped, long, thick, and tenacious, matted together at the base,
and blackish-green. The species grows in tufts on eel-grass and
algae, and is often found floating free. It is common in summer
everywhere south of Cape Cod and on the Pacific coast.

^L. ferruginea^ or ^aestuarii^. In this species the filaments are
thin, soft, and without stability (flaccid), so that they lie flat
like a thin stratum. They are verdigris-green in color, and are
found in brackish pools and ditches and on muddy shores near the
sea. [pg051]

TABLE SHOWING THE CLASSIFICATION OF THE GRASS-GREEN SEAWEEDS DESCRIBED IN THIS CHAPTER

Class =ALGAE=

Subclass =Chlorophyceae= (/Grass-Green Seaweeds/)

Order Genus Species

=CONFERVACEAE= ^Ulothrix^

^Chaetomorpha^ ^C. melagonium^
^C. aerea^
^C. linum^

^Cladophora^ ^C. arcta^
^C. rupestris^
^C. gracilis^

=ULVACEAE= ^Ulva^ ^U. lactuca^
^U. latissima^

^Enteromorpha^ ^E. clathrata^
^E. compressa^
^E. intestinalis^
^E. lanceolata^

^Monostroma^

Group =Siphoneae=

=VALONIACEAE= ^Chamaedoris^ ^C. annulata^

^Anadyomene^ ^A. flabellata^

=DASYCLADACEAE= ^Acetabularia^ ^A. crenulata^

^Dasycladus^ ^D. occidentalis^

^Cymopolia^ ^C. barbata^

=UDOTEACEAE= ^Penicillus^ ^P. dumentosus^
^P. capitatus^
^P. Ph[oe]nix^

^Udotea^ ^U. flabellata^
^U. conglutinata^

^Halimeda^ ^H. tuna^
^H. tridens^
^H. opuntia^

=CODIACEAE= ^Bryopsis^ ^B. plumosa^

^Codium^ ^C. tomentosum^

=CAULERPACEAE= ^Caulerpa^ ^C. prolifera^
^C. Mexicana^
^C. plumosa^
^C. Wurdemanii^

[pg052]

GRASS-GREEN SEAWEEDS

"There can hardly be a more fascinating group of plants than this, whether to the strictly scientific botanist or to the more catholic lover of nature. The green algae are among the most widely diffused of plant forms. They grow practically in every place where enough moisture, together with light and air, is to be had. Between tide-marks on almost every coast, floating on the surface of the deep sea, covering damp earth, walls, palings, and tree-trunks, sticking to the surface of leaves in the moist atmosphere of tropical forests and jungles, and inhabiting almost every river, brook, pond, ditch, or casual pool of rain-water in all quarters of the globe, are members of this ubiquitous group to be found."[3]

[Footnote 3: Kerner.]

The grass-green seaweeds are more simple in structure, and therefore are lower in order, than the red or brown algae. They are among the lowest of all plants, many of them being minute single cells. They abound in fresh as well as in salt water, and in this respect differ from the other groups, the red and the brown algae being almost exclusively marine plants.

As one approaches the shore, the attention is often attracted by the green mantle which covers everything overflowed by the tides. This consists largely of the confervoid algae, which are very abundant and are found almost everywhere. They are dense tufts of fine thread-like plants, often matted at the base; sometimes they are sponge-like, floating masses.

The =Ulvaceae=, the plants next higher in order, are the first which assume ribbon- and leaf-like expansions, and usually first engage the attention of the collector. [pg053]

In the green algae are found the extreme forms of one-celled plants. In ^Pleurococcus^ the cell is microscopic in size. In the =Siphoneae= the plant still consists of a single cell, but it attains large dimensions and develops into forms resembling, in outward appearance, leaf, stem, and root (see /Caulerpa/).

Other plants consist of single rows of cells, called filaments (=Confervaceae=), or of cells arranged in layers or flat surfaces, called membranes (=Ulvaceae=).

ORDER =CONFERVACEAE=

The silkweeds. This order is characterized by cylindrical cells strung end to end, forming threads or filaments, branched and unbranched. The plants inhabit both fresh and salt water, and are very abundant and widely distributed. They grow in dense tufts, often matted at the base.

GENUS ^Ulothrix^

A yellow-green, unbranched, decumbent, soft, hair-like fleece on the surface of rocks, extending indefinitely. This genus differs from /Chaetomorpha/ in the character of its filaments, which are soft and gelatinous in ^Ulothrix^, but bristle-like and wiry in /Chaetomorpha/.

GENUS ^Chaetomorpha^

The frond is filiform; the filaments are coarse, rigid, and unbranched. In some species the filaments grow straight and in tufts from a definite base; in others they are twisted together and are prostrate. Often they are found floating in masses. In ^C. tortuosa^ the filaments are as fine as human hair, but rigid, and so closely interwoven as to resemble a layer of wool on the rocks. The cell-divisions give a striped appearance to the filaments when dry.

^C. melagonium.^ This species is dark green, with filaments erect,
coarse as a double bristle, and wiry; five to twelve inches long.
It is found in rock pools from Boston northward. It does not adhere
to paper in drying, and loses its color if immersed in fresh water.
(Plate III.)

^C. aerea.^ Yellowish-green, with filaments erect and less rigid
than [pg054] in /C. melagonium/, which it otherwise resembles;
tufts three to twelve inches long; cell-divisions very marked. This
species is found in rock pools from Cape Cod to New York Bay.

^C. linum.^ Bright green; filaments coarse, rigid, twisted
together, and prostrate. It is found floating in masses and forming
strata on rocks and gravel from New York northward. It is thought
by some that this, as well as ^C. picquotiana^, which it closely
resembles, is not a true species, but consists of the mature plants
of the species /C. melagonium/ and /C. aerea/, which have become
detached from their holdfasts and have continued to grow. (Plate
III.)

GENUS ^Cladophora^

("/Branch-bearing/")

Frond filiform, branched. There are many species of ^Cladophora^, which differ from one another in their branching, color, and size. They abound on rocks at low-water mark, in tide-pools, in muddy ditches, and on wharves. They are especially characterized by being so profusely branched as to form tufts or spherical masses, by which the collector can easily distinguish the genus.

^C. arcta.^ Bright, glossy green; filaments fine, erect, much
branched, two to eight inches long; tufts dense, more or less
entangled, and in bunches, giving a starry effect. The species is
common on rocks near low-water mark from New York northward. The
plants vary slightly in appearance with the season. (Plate III.)

^C. rupestris.^ Dark green; filaments straight, rigid, tufted;
branches crowded; many branchlets flattened against the filaments,
so that the alga somewhat resembles grass; five to ten inches long.
The cell-divisions show plainly. Plants of this species do not
adhere to paper in drying. They are found on rocks at low-water
mark, and are common on the northern New England coast. (Plate III.)

^C. gracilis.^ Bright yellow-green; filaments very fine, loosely
tufted, three to twelve inches long, soft, silky, much branched;
branches rather short, and branchlets more or less curved and
arranged in a comb-like manner. It grows on wharves, in muddy
pools, and on eel-grass. (Plate IV.)

ORDER =ULVACEAE=

The plants of this order are, with few exceptions, formed of celled surfaces and show the earliest type of an expanded leaf. The cells form thin membranes, which sometimes are broad surfaces of no definite shape, sometimes are narrow and ribbon-like, or they may be simple or branched tubes. When the membrane [pg055] consists of a single layer of cells it is ^Monostroma^ ("one layer"); when it consists of a double layer it is ^Ulva^; when the layers separate, the thallus becomes hollow, and it is then ^Enteromorpha^. These plants are mostly a brilliant grass-green in color, are silky in texture, and are attached by a small disk to rocks and stones. They abound everywhere, and are commonly known as /green laver/.

GENUS ^Ulva^

Frond a thin, silky, flat membrane, sometimes leaf-like, again an extended surface of no definite shape. These are the largest green algae. They are common everywhere.

^U. lactuca^, the sea-lettuce. Frond a flat membrane of various
shapes, sometimes orbicular, again deeply incised, often
ribbon-like; margin always much waved or ruffled. In the variety
^rigida^ the frond is oval in outline, not very large, and quite
firm or rigid. The species is found on rocks exposed to the action
of the waves. (Plate IV.)

^U. latissima.^ Frond a flat, expanded membrane of indefinite
shape, but general outline oval, never ribbon-like; attains a
size of twelve to twenty-four inches; often deeply lobed, very
waved, often perforated with holes; membrane brilliant green,
thin, smooth, glossy. It grows apart or in tufts, and is found
everywhere, in all stages of growth. It is the largest species of
/Ulva/, and is very common on muddy shores.

GENUS ^Enteromorpha^

Fronds tubular, simple or branched, sometimes inflated. The tubes vary in size in different species and also in the same species, some being fine like a hair, others large, and flat or inflated. The genus is widely distributed and very abundant. Species of ^Enteromorpha^ grow on the bottoms of ships, and in nautical language are called /grass/.

^E. clathrata.^ Fronds thread-like, tubular, branched, and branches
beset with numerous fine branchlets; densely tufted, soft. Common
everywhere. (Plate IV.)

^E. compressa.^ Fronds long, slender, branched, tufted; branches
simple, compressed, extending from main central branch, obtuse
at ends, but attenuated at base. The species is very abundant
everywhere, and is a useful plant for the aquarium. (Plate V.)

^E. intestinalis.^ Single, long, inflated tubes or sacs, obtuse at
the apex, very attenuated at the base; fronds often crimped and
twisted, resembling an intestine, whence the name. (Plate V.)
[pg056]

^E. lanceolata.^ Formerly called /Ulva Linza/. Frond narrow,
ribbon-like, six to twelve inches long, one inch to two inches
wide; blunt or pointed at apex, tapering at base; attached by a
disk; edges much ruffled; bright green, soft, thin.

GENUS ^Monostroma^

This genus resembles /Ulva/, but is more delicate since it has but one layer of cells, as its name implies. The frond is usually sac-like at first, then breaks apart, leaving a thin, semi-transparent membrane of no definite shape.

GROUP =SIPHONEAE=

The distinct and peculiar character of this group is that in each individual the whole plant consists of but one cell. There are many genera, some of which are plants of elaborate form and considerable size, but always the one cell expands and branches without dividing the elongated cavity with septa, or plates of division. In ^Caulerpa^ the stability of the plant is secured by numerous fibrils which emanate from the interior of the cell, forming a spongy network of interlacing filaments. In other orders the branches gain support from incrustation, from interlacing, and from cohering on the edges.

ORDER =VALONIACEAE=

The algae of this order are found only in tropical or subtropical waters. Their holdfasts resemble fibrous roots and penetrate the sand or coral on which they grow.

GENUS ^Chamaedoris^

^C. annulata.^ When young this alga consists of an annulated tube
formed of a single cell. The annular constrictions occur at short
intervals, giving it the appearance of being jointed. It grows to
the height of two to three inches, when it ceases to lengthen and
produces a dense mass of filaments, forming a head or spherical
tuft one inch or more in diameter. It is bright grass-green in
color, rather rigid and tough, and when mature is thinly coated
with carbonate of lime. The holdfast is a tuft of fibers. The
species is found at Key West and is a native of the West Indies.

GENUS ^Anadyomene^

^A. flabellata.^ Frond composed entirely of branching filaments,
which unite and form an undulating, rigid membranaceous surface,
which seems like a network of veins. The species grows in bunches
on short stems in the fissures of tidal rocks, and at first view
resembles young /Ulva/. It is a very curious and beautiful alga,
and should be examined with a glass. It is one inch to four inches
in diameter when full-grown. (Plate V.)

ORDER =DASYCLADACEAE=

This order also inhabits only tropical or subtropical seas. It is placed in this group, although only the main axis is unicellular. The one-celled axis is surmounted or encircled by whorls of minute filaments or branchlets (/ramuli/), which protrude through small holes and are either persistent or deciduous. In the latter case the fallen filaments leave disk-like scars on the stem.

GENUS ^Acetabularia^

^A. crenulata.^ This little alga resembles a mushroom of the
/Agaricus/ variety or gilled species, and so is easily identified.
It is thinly incrusted with lime and is found on rocks and coral,
within tide-marks, on the Florida reefs. When full-grown the stipe
is two to three inches long and the cap one half of an inch in
diameter. (Plate VI.)

GENUS ^Dasycladus^

Fronds destitute of calcareous matter, soft, cylindrical or club-shaped; single unicellular axis, beset with fine filaments or ramuli.

^D. occidentalis.^ Frond club-shaped, one to two inches high, one
half of an inch or less in diameter; covered with whorls of fine
filaments, making the fronds almost spongy; substance soft but
tough; dark green. These plants have been compared to foxes' tails.
They grow in bunches on rocks between tide-marks. (Plate VI.)

GENUS ^Cymopolia^

^C. barbata.^ Frond branched, dividing regularly in pairs; thickly
incrusted with lime. Annular constrictions at short intervals give
the branches the appearance of strings of beads. Each section
is covered with pores or scars of fallen ramuli. The branches
terminate in tufts of fine filaments. [pg058]

ORDER =UDOTEACEAE=

GENUS ^Penicillus^

The merman's shaving-brush, characteristic of coral reefs.

^P. dumentosus.^ Holdfast much branched, like a fibrous root, and
penetrating deep into the coral or sand; stem short, thick, more
or less flattened, sometimes hollow, covered with velvety scurf;
top covered with loosely spreading tuft of soft filaments three to
six inches long, which branch repeatedly in pairs (dichotomous);
color deep green. When old, these plants are incrusted with a thin,
porous layer of carbonate of lime. (Plate VI.)

^P. capitatus.^ Holdfast a dense mass of fibers two or more inches
long; stipe one to five inches long, one fourth to one third of an
inch in diameter, usually cylindrical, sometimes wider at top than
at base, sometimes flattened; thickly incrusted with lime, which is
smooth and often polished; top a dense, spherical mass of filaments
one to two inches in diameter; filaments branching dichotomously,
and rigid from incrustation of lime.

^P. Ph[oe]nix.^ Stipe cylindrical, one to three inches long,
one fourth of an inch in diameter, thickly incrusted with lime,
smooth; capitulum or head ovoid, and composed of filaments which
are incrusted with lime and coherent, forming many distinct, flat,
wedge-shaped, level-topped, spreading laminae. This species is found
at Key West.

GENUS ^Udotea^

^U. flabellata.^ Short, flattened stem, expanding into a broad,
fan-shaped, smooth frond, concentrically zoned; margin wavy;
thickly incrusted with lime. Abundant at Key West.

^U. conglutinata.^ Deeply descending root; stem expanding into
fan-shaped frond; entire, lobed, or irregularly torn; slightly
incrusted with lime. The frond is composed of longitudinally
parallel, adherent filaments, which are visible, giving a striated,
rough surface. (Plate VI.)

GENUS ^Halimeda^

This genus resembles the corallines externally, and is abundant on coral reefs. It appears as if formed of separate parts, resembling a series of heart- or kidney-shaped segments strung together. The plants are more or less incrusted with lime. The branching holdfast grasps particles of sand, and with them forms a solid ball.

^H. tuna.^ Articulations roundish or half kidney-shaped, one half
to three quarters of an inch broad; frond flat, smooth, and thinner
than most species; bright green; somewhat flexible. (Plate VII.)

^H. tridens.^ Fronds solitary, erect; base composed of
confluent articulations; above divided into numerous branches
of articulations, which are all flat, and in one plane giving a
fan-shaped outline; middle joints wedge-shaped; upper ones divided
into three lobes, frequently bearing articulations at the summit of
each lobe; thinly incrusted with lime; color bright green. (Plate
VII.)

^H. opuntia.^ Articulations kidney-shaped, flat, rather thin;
margins scalloped; irregularly branched and spreading; dense tufts.

ORDER =CODIACEAE=

GENUS ^Bryopsis^

("/Moss-like/")

There are said to be about twenty species of this genus. They are distinguished by the manner of branching, but are not very definitely marked. All are erect, one-celled, branching stalks, and are feather-like in appearance.

^B. plumosa.^ Fronds branched twice or more; branchlets or pinnules
tapering as they rise on the stalk, giving a triangular outline;
stalk naked below; plants a vivid dark green in color, two to six
inches long, growing in tufts on wharves and stones at low-water
mark and in tide-pools. It is common along the whole Atlantic and
Pacific coasts. It is well to use salt water for mounting this
alga, since the green coloring-matter or granular endochrome with
which it is filled easily escapes. (Plate VII.)

GENUS ^Codium^

^C. tomentosum.^ This is called the commonest seaweed in the world.
It is abundant in every latitude, yet it does not appear on the
eastern coast of North America. It is found on the gulf coast of
Florida and is plentiful on the Pacific coast. The fronds are often
a foot long, composed of closely packed, club-shaped branches
dividing in a forking manner, and densely covered with fine
filaments which give them a soft, sponge-like texture. (Plate VII.)

ORDER =CAULERPACEAE=

GENUS ^Caulerpa^

(/From two Greek words meaning "stem" and "creep"/)

/Caulerpa/ is the only genus of its order, but it contains about a hundred species, many of which resemble mosses, ferns, or cacti. Each plant is composed of a single cell, however much it may be [pg060] ramified. The frond consists of a prostrate stem, from the lower side of which root-like fibers or holdfasts descend into the hard sand or coral, and from the upper side leaf- and branch-like secondary fronds arise. These plants grow luxuriantly in tropical waters, extending over large surfaces, and are the chief food of turtles. (Plate VIII.)

^C. prolifera.^ Frond or lamina flat and leaf-like, two to four
inches long, one half to three quarters of an inch wide, either
simple or once forked; margin entire. Similar laminae spring from
the surface or from the edge or base of the different leaf-like
portions. Laminae rise from the upper side of the creeping, rooting
stem. Its substance is somewhat horny and translucent.

^C. Mexicana.^ Prostrate, creeping stem, with rootlets or holdfasts
below, and leaf-like fronds above; fronds simple or with one or
two branches deeply cut in narrow lobes nearly to the center. The
species abounds at Key West. (Plate VIII.)

II

OLIVE-GREEN AND BROWN SEAWEEDS (PHAEOPHYCEAE)

TABLE SHOWING THE CLASSIFICATION OF THE OLIVE-GREEN AND BROWN SEAWEEDS DESCRIBED IN THIS CHAPTER

Class =ALGAE=

Subclass =Phaeophyceae= (/Olive-Green and Brown Seaweeds/)

Orders Genera Species

=ECTOCARPACEAE= ^Ectocarpus^ ^E. littoralis^
^E. siliculosus^
^E. viridis^
^E. tomentosus^

=SPHACELARIACEAE= ^Sphacelaria^ ^S. cirrhosa^
^S. radicans^
^Cladostephus^ ^C. verticillatus^

=RALFSIACEAE= ^Ralfsia^

=ENC[OE]LIACEAE= ^Punctaria^ ^P. latifolia^
^P. tenuissima^
^P. plantaginea^
^Asperococcus^ ^A. echinatus^
^Phyllitis^ ^P. fascia^

=DESMARESTIACEAE= ^Desmarestia^ ^D. viridis^
^D. aculeata^
^D. ligulata^
^Arthrocladia^ ^A. villosa^

=DICTYOSIPHONACEAE= ^Dictyosiphon^ ^D. f[oe]niculaceus^

=ELACHISTACEAE= ^Elachista^

=CHORDARIACEAE= ^Chordaria^ ^C. flagelliformis^
^Mesogl[oe]a^ ^M. virescens^
^M. divaricata^
^Leathesia^
^Myrionema^

=LAMINARIACEAE= ^Chorda^ ^C. filum^

^Alaria^ ^A. esculenta^

^Agarum^ ^A. Turneri^

^Laminaria^ ^L. longicruris^
^L. saccharina^
^L. digitata^
^Macrocystis^
^Nereocystis^
^Lessonia^
^Thalassiophyllum^

=DICTYOTACEAE= ^Dictyota^ ^D. fasciola^
^D. dichotoma^
^Zonaria^ ^Z. lobata^
^Taonia^ ^T. atomaria^
^Padina^ ^P. pavonia^
^Haliseris^ ^H. polypodioides^

=CUTLERIACEAE= ^Cutleria^ ^C. multifida^

=FUCACEAE= ^Himanthalia^ ^H. lorea^
^Fucus^ ^F. vesiculosus^
^F. serratus^
^F. furcatus^
^F. ceranoides^

^Ascophyllum^ ^A. nodosum^
^Phyllospora^ ^P. Menziesii^
^Cystoseira^ ^C. expansa^
^Halidrys^ ^H. osmunda^
^Sargassum^ ^S. vulgare^
^S. Montagnei^
^S. bacciferum^

[pg064]

OLIVE-GREEN AND BROWN SEAWEEDS

This subclass contains some of the most remarkable of the seaweeds. It is especially notable for the diversity of its plant forms, which range from filaments to plants which appear to have stems and leaves (/Sargassum/). The species vary in size from very small fronds to those of immense size (the /Laminariaceae/). It includes /Fucus/ (the rockweeds), a very conspicuous genus, which furnishes fully three fourths of the vegetable covering of the tidal rocks in the localities in which it grows.

ORDER =ECTOCARPACEAE=

This order comprises many species of branched, filamentous plants, some of which are of hair-like fineness and form beautiful feathery tufts of brownish or olive-green color. They resemble, except in their tawny color, the green alga /Cladophora/.

The name is derived from Greek words meaning "outside" and "fruit," the spores of the plants being borne on the branches.

The species are determined by the arrangement of the spores, according as they are in the pod-like branches, in groups, or in cases on stalks. Since these differences are not perceptible to the naked eye, it is impracticable to describe many species, or for the amateur collector to try to separate them.

GENUS ^Ectocarpus^

^E. littoralis.^ Filaments fine, in dense tufts, interwoven, six to
twelve inches long; pod linear in the substance of the branches;
color olive-green. This is the most common species of /Ectocarpus/,
and grows abundantly everywhere, appearing like large, fine,
dull-green plumes. (Plate IX.) [pg065]

^E. siliculosus.^ Tufts loosely entangled at the base, free and
feathery above, of indefinite length; spores in pod-like forms at
the ends of the branches. Common on the larger algae and on wharves.

^E. viridis.^ Tufts a little more loose and expanding than in /E.
siliculosus/; spores in pods at the base of the branches. (Plate
IX.)

^E. tomentosus.^ Fine filaments, densely interwoven into rope-like,
spongy masses, two to four inches long; yellowish-brown; pods on
stalks. Found in summer growing on /Fucus/.

ORDER =SPHACELARIACEAE=

GENUS ^Sphacelaria^

^S. cirrhosa.^ Olive-brown; branched, feathery filaments, one
half of an inch to two inches long. Each branch ends with an
oblong, swollen cell containing a dark granular mass which gives
it a withered appearance. These cells can be seen with a strong
pocket-lens. It forms dense, globe-like tufts on /Fucus/.

^S. radicans.^ Filaments one half of an inch to one inch high;
branches few and hairy. It forms a dense, grass-like covering, of
indefinite extent, on the under side of muddy rocks. Found on the
New England coast.

GENUS ^Cladostephus^

^C. verticillatus.^ Fronds bristle-like, dividing regularly;
covered with whorls of branchlets set close to the stems, each
whorl overlapping the previous one, giving the plant a spongy
appearance. (Plate IX.)

ORDER =RALFSIACEAE=

GENUS ^Ralfsia^

The species of this genus are brown, leathery, crustaceous expansions of indefinite form, one inch to six inches in diameter, resembling lichens. They appear on rocks in shallow, exposed pools.

ORDER =ENC[OE]LIACEAE=

GENUS ^Punctaria^

Dotted-weeds. Fronds pale olive-green, membranaceous, leaf-like, with short stem; covered with spores which appear like dots.

^P. latifolia.^ Frond pale green, four to twelve inches long, one
inch to five inches wide, leaf-like, and tapering suddenly to a
short stalk; much [pg066] waved on margin; substance soft and
thin; dotted with spores. In the young plants fine hairs emerge
from the dots, but disappear later, and the fronds become darker
and more rigid. Found in summer on rocks and on other algae on the
Long Island and New England coasts.

^P. tenuissima.^ Fronds smaller and more slender than in /P.
latifolia/; thin and delicate. Found on eel-grass and /Chorda
filum/.

^P. plantaginea.^ Fronds dark brown, leathery, leaf-like, blunt or
wedge-shaped on top; dense clusters of hairs on the dots; six to
twelve inches long, one inch to one and a half inches wide.

GENUS ^Asperococcus^

This genus differs from /Punctaria/ in having a tubular instead of a flat frond. (Plate IX.)

^A. echinatus.^ Resembles /Enteromorpha/ in being tubular;
compressed or inflated; obtuse at the apex; attenuated at the
base. It differs from /Enteromorpha/ in being olive in color, and
in being covered with small oblong dots of darker shade. When the
plant is young the dots are hairy. It grows in clusters, two to
eighteen inches long, one half of an inch to one inch wide. Common
along the New England coast.

GENUS ^Phyllitis^

^P. fascia.^ Fronds light olive-green, leaf-like, three to six
inches long, one fourth to one half of an inch wide; margin entire,
slightly waved; contracted at base to short stalk; attached
by disk. This species grows in bunches on rocks and stones at
low-water mark, and is very common everywhere. (Plate X.)

ORDER =DESMARESTIACEAE=

(/Named for M. Desmarest, a French naturalist/)

GENUS ^Desmarestia^

^D. viridis.^ Filaments cylindrical, about as thick as a bristle;
branches opposite, in pairs, at intervals on the main stem. The
branches branch again and continue to be disposed in the same
manner. All are long and ultimately become very fine. The color is
olive-green, becoming verdigris-green when exposed to the air for
a short time or placed in fresh water. The species grows in deep
tide-pools and below low-water mark, forming fine, feathery plumes,
often a yard long, which give submerged rocks the appearance of a
luxuriant garden. (Plate X.)

^D. aculeata^ ("spiny"). Fronds cylindrical at base, flattened
above; branches long and straight, arranged alternately, when young
beset with pencils of fine hairs, often one half of an inch long,
which, later, fall off, leaving alternate spines along the edges of
the flattened branches. It [pg067] grows from one foot to six
feet in length, below low-water mark, and is found washed ashore.
It is an attractive plant in the spring, but is brown and coarse
when old. Common everywhere. (Plate X.)

^D. ligulata.^ Fronds two to six feet long, pinnate, having a
flat main stem one half of an inch or more wide, with opposite
flat branches; leaflets arranged along the edges of the branches,
pointed at each end, and bordered with forward-pointing spines. It
is found washed ashore, in abundance, in California, but is not
found on the Atlantic coast. (Plate X.)

GENUS ^Arthrocladia^

^A. villosa.^ Olive-brown filaments, resembling fine, knotted
threads, each knob having a whorl of delicate filaments. It grows
from six inches to three feet long, in deep water. It is rare, but
is occasionally found on the New England coast.

ORDER =DICTYOSIPHONACEAE=

GENUS ^Dictyosiphon^

^D. f[oe]niculaceus.^ Fronds filiform, bristle-like, branching
into delicate, hair-like branches; yellowish-brown. It resembles
/Chordaria flagelliformis/, but is much finer. (Plate XI.)

ORDER =ELACHISTACEAE=

GENUS ^Elachista^

The plants of this genus are small, olive-colored, unbranched, hair-like filaments, growing in dense, radiating tufts, one half of an inch in height, on /Fucus/. They are interesting to the microscopist, but not to the collector.

ORDER =CHORDARIACEAE=

("/Cord-like/")

GENUS ^Chordaria^

^C. flagelliformis^ ("whip-like"). Firm, leathery, somewhat
elastic, slimy strings, six to twenty-four inches long, and twice
as thick as a bristle; branches mostly undivided, short or long,
irregularly placed on the main axis, and curving inward at the
top of the frond; main axis not extending as far as the branches;
blackish in color; attached by a disk to stones and shells;
solitary or in bunches. It is common along the New England coast.
(Plate XI.) [pg068]

GENUS ^Mesogl[oe]a^

^M. virescens.^ Soft, slimy filaments, with branches and
branchlets; olive-green. (Plate XI.)

^M. divaricata.^ Fronds two to twenty-four inches high; branching
irregularly, and generally without definite main axis; branches
flexuous, solid at first, later hollow; branchlets short and
wide-spreading. Common from Cape Cod southward; abundant in Long
Island Sound. (Plate XI.)

GENUS ^Leathesia^

This singular alga resembles a tuber and cannot be mistaken for any other plant. Its fronds are gelatinous, fleshy balls, one half of an inch to two inches in diameter, at first solid, afterward lobed and hollow. It grows singly or in bunches on algae and on sand-covered rocks, and is found in summer on every coast. The common species is known as /L. difformis/ or /L. tuberiformis/.

GENUS ^Myrionema^

Minute algae which grow on other plants and which appear like dark spots, or, at first, like stains, on /Ulva/, /Enteromorpha/, and small red algae. These spots, which to the naked eye appear like decay, show, under the microscope, a jelly-like substance full of beaded filaments.

ORDER =LAMINARIACEAE=

The plants of this order have large and coarse fronds (some attaining an immense size), with stems, branching root-like holdfasts, and expanded leaf-like laminae. They are leather-like, not articulated, olive-green or brown in color, and sometimes yellow and semi-transparent. They grow in deep water and are found washed ashore. Sometimes small plants are found in deep tide-pools at low-water mark. Some species are perennial. In these instances the stems only survive, and the laminae are reproduced annually. The new growth takes place at the apex of the stem. The old lamina is pushed off, but is held on the summit of the new growth until the latter has matured.

niculaceus. Chordaria flagelliformis. Mesogl[oe]a virescens. Mesogl[oe]a divaricata.]

In the genus /Chorda/ the fronds are cylindrical; in /Agarum/ [pg069] the laminae are perforated; in /Alaria/ there are wing-like leaflets below the laminae.

The /Laminariaceae/ and /Fucaceae/ are the seaweeds used in making kelp. For this the algae are burned, and the ash is then separated into its different mineral constituents and used for various manufacturing purposes.

GENUS ^Chorda^

^C. filum.^ Entire frond cylindrical, divided internally by
transverse septa; one fourth to one half of an inch in diameter,
tapering at each end; ordinarily one to twelve feet long, but
sometimes attaining a length of forty feet. When young the frond
is covered with fine, transparent hairs; later it is brown and
leather-like. The growth takes place at the base, just above the
disk-like holdfast, and at the apex it is constantly dying off. The
species is common on Northern shores, at and below low-water mark.
Often it is in masses which seem like meadows of waving grass under
water. Various small algae and many zooephytes are to be found on the
fronds. (Plate XII.)

GENUS ^Alaria^

This genus is readily distinguishable by the fact that it has leaflets below the lamina. It is found north of Cape Cod.

^A. esculenta.^ Stem compressed, four to twelve inches long, one
fourth to one half of an inch wide, and running like a midrib
through the lamina; lamina one to ten feet long, two to ten inches
wide, frequently torn and ragged; margin wavy; leaflets three to
eight inches long and without midrib, growing on both sides of the
stem, below the lamina. The spores are produced in the leaflets in
the autumn. This is an edible alga and is used as food in Scotland
and Ireland, where it is called henware, badderlocks, murlins, and
so on. (Plate XII.)

GENUS ^Agarum^

The sea-colanders.

^A. Turneri.^ Stem two to twelve inches long, round below,
flattened above, and extending like a midrib through the lamina;
lamina one foot to four feet long, with holes over the whole
surface; margin wavy. The perforations in the lamina are produced
by conical hollow papillae which cover the young frond and which at
length burst, leaving a hole which enlarges as the plant expands.
This species is found from Cape Cod to Greenland.

There are other species, which differ from this one in the size of
the perforations, the shape of the lamina, and the prominence of
the midrib. Harvey describes the plant as an arctic genus growing
ten to twelve feet long. (Plate XII.) [pg070]

GENUS ^Laminaria^

The plants of this genus are all large, varying from one foot to twelve feet or more in length. They are of wide geographical range, and are more numerous in species than any others of the order. They are commonly known as oarweeds, tangle, devil's-aprons, sole-leather, kelp, sea-furbelows, and so on.

^L. longicruris^ ("long-stalked"). Stem six to twelve feet long,
one to two inches thick, slender and solid at base, hollow and
inflated at the middle, contracted at the top; attached by a
strong, branching, root-like holdfast; color light brown. The
large, single, leaf-like lamina, usually shorter than the stem, is
five to twenty feet long, two to three feet broad, with much waved
and folded margin, outlined with two rows of depressed spots. The
spores form a band in the center of the blade. Found from Cape Cod
northward and on the Pacific coast.

^L. saccharina^, the sea-tangle. This species differs from /L.
longicruris/ in having a short, solid stem and narrow, ribbon-like
lamina. Stem three inches to four feet long; lamina three to
thirty feet long, six to eighteen inches wide, with central
band of depressed spots; margin much waved; color olive-green,
semi-transparent. It is named from the saccharine matter, called
/mannite/, which it contains. Found on northern shores of the
Atlantic and the Pacific oceans. (Plate XII.)

^L. digitata^ ("fingered"). Stem one to five feet long, thick,
round, and solid; lamina oval at base, leathery, smooth, brown,
deeply cleft into segments of unequal breadth. It is named from the
hand-like form of the lamina. This species is found in Long Island
Sound, but is not common south of Cape Cod. The stem is used by
fishermen for knife-handles. Pieces of it, placed on the blades
while green, contract in drying and become solid. (Plate XIII.)

For the genera ^Macrocystis^, ^Nereocystis^, ^Lessonia^, and ^Thalassiophyllum^, see the Introduction, pages 35, 36.

ORDER =DICTYOTACEAE=

GENUS ^Dictyota^

^D. fasciola.^ Fronds olive-brown, expanded, membranaceous, erect,
flat; many times forked narrow branches; grows in tufts six to ten
inches long, matted at the base.

^D. dichotoma.^ Same as /D. fasciola/, except that the divisions of
the forked frond are one eighth to one half of an inch wide. Found
in tide-pools in Southern waters. (Plate XIII.)

GENUS ^Zonaria^

^Z. lobata.^ Thallus flat, fan-shaped, but not so rounded as
in /Padina pavonia/, twelve or more inches in height, cleft
irregularly into many [pg071] narrow lobes, the clefts
extending nearly or quite to the base; olive-green, with concentric
zones of darker color; edges thin and bordered with a dark line.
Found in southern California and in tropical and subtropical seas.

GENUS ^Taonia^

^T. atomaria.^ Spreading, fan-shaped frond; clefts irregular and
not extending to the basal stem; spores arranged in dark wavy
lines and spots on the frond, giving it a mottled appearance and
beautiful gradation of color. Found in tropical seas. (Plate XIII.)

GENUS ^Padina^

^P. pavonia^, the peacock's-tail. Frond broadly fan-shaped;
substance between membranaceous and leathery; powdery on the
outer surface; deeply and variously cleft or entire; several
laminae emanating from a stalk-like base; each lamina fan-shaped;
concentric lines numerous; variegated in zones. This beautiful alga
is always regarded as a prize. It is found on stones at low-water
mark, and is not uncommon south of Charleston, South Carolina, but
is more luxuriant in tropical seas. (Plate XIII.)

GENUS ^Haliseris^

The sea-endive.

^H. polypodioides.^ Fronds flat, forked, notched on lower part;
divisions about one quarter of an inch wide; distinct midrib;
olive-green; grows in tufts. It is found in North and South
Carolina, and is abundant on the Florida Keys. (Plate XIV.)

ORDER =CUTLERIACEAE=

GENUS ^Cutleria^

^C. multifida.^ Frond erect, flat; branches in a forking manner;
ultimate branches fine and short, and with branchlets on the tips.
This species resembles /Taonia/. It is found in Southern waters.
(Plate XIV.)

ORDER =FUCACEAE=

GENUS ^Himanthalia^

^H. lorea^, the sea-thong. A cup-shaped base, from the center of
which arises a flat, strap-like frond one fourth to one half of an
inch wide and two to twenty feet long, branching dichotomously (or
by forking), and dotted with pits, or conceptacles, in which the
spores are formed. Found in the extreme North. [pg072]

GENUS ^Fucus^

The rockweeds. The plants of this genus grow in thick bunches, and are found in great abundance between tide-marks. The plants are attached by sucker-like disks to the rocks, from which they hang like fringe when the tide recedes; when it rises they float and sway in the water in beautiful bouquet-like forms. In color they are brown or olive-green, in texture thick and leathery, but they sometimes expand into thin membranes. They are many times forked in the same plane, which produces a flat thallus. They often have a distinct midrib. The air-vessels, whose function it is to float the plant, are disposed along the midrib, usually in pairs.

The species are named according to the divisions of the frond, and the disposition, or presence, of the air-bladders and the /conceptacles/, or spore-chambers.

The conceptacles congregate in particular portions of the frond and give its surface a roughness which is very perceptible; such portions are then known as the /receptacles/. In /Fucus/ this usually occurs on the bulbous extremities of the branches. Under the microscope a section of one of these little pointed spots shows a spherical cavity filled with a beautiful arrangement of /paraphyses/, or threads, some of which hold spores, while others protrude through a small opening in the outer membrane. Conceptacles are peculiar to the order =Fucaceae=. In them spore-production is carried on in a manner as complicated as is the formation of seeds in flowering plants. Although rockweeds are such a conspicuous feature of sea-shore vegetation, two species only, /Fucus vesiculosus/ and /Ascophyllum nodosum/ (formerly called /Fucus nodosus/), are common on the Atlantic coast, and these do not occur south of New York, owing to the fact that a long stretch of sand-beach extends beyond that point.

^F. vesiculosus.^ Midrib distinct through all the forked branches;
margin entire, often wavy; air-vessels spherical or oblong, usually
in pairs along the midrib; receptacles on terminal branches, which
are swollen and filled with gelatinous matter, heart-shaped or
forked, in oblong or pointed divisions; frond tough and leathery,
often two feet long. (Plate XIV.)

^F. serratus.^ Frond distinctly toothed or serrated along the
margin; midrib conspicuous through the main axis and forked
branchings; no air-vessels. This species is rare on the Atlantic
coast. (Plate XV.)

^F. furcatus.^ Frond narrow, tough, without air-vessels; regular
forked branching; midrib distinct below, inconspicuous above;
receptacles long, narrow, not inflated. Found from Boston northward.

^F. ceranoides.^ Frond flat, rather membranaceous, or less leathery
than in the preceding species; repeatedly forked; midrib not
running through every division; no air-vessels. (Plate XV.)

GENUS ^Ascophyllum^

^A. nodosum.^ This species, formerly called /Fucus nodosus/, is
next to /Fucus vesiculosus/ the most common rockweed. Frond one to
five feet long, dark brown, strap-like, leathery; width of main
stems one fourth of an inch or more, and uniform throughout; large,
single, oblong air-vessels distend the frond at intervals. Branches
of various length emerge from the sides of the main stem. Ovoid or
ellipsoidal branchlets or receptacles, single or in groups, occur
at intervals along the sides of both stem and branches. These fall
off after a time and are found in quantities in tide-pools. (Plate
XV.)

GENUS ^Phyllospora^

^P. Menziesii.^ Branching holdfast; short stem which immediately
divides into strap-like branches; branches edged with leaves
varying in length, rounded at top, narrow, stalked at base; leaves
placed at intervals, or crowded together, and interspersed with
air-vessels which are often tipped with leaflets; stems expand at
summit into leaf-like laminae and are edged with leaflets at the
base; plant often one hundred and twenty feet or more in length;
tough and leathery in substance. Very common on the California
coast. (Plate XVI.)

GENUS ^Cystoseira^

^C. expansa.^ Frond long, slender, repeatedly branched; air-vessels
ellipsoidal and "chained" together in the lower half of the
branches. The plant grows in deep water, ad shows iridescent colors
when seen through the water. It is found on the California coast.

GENUS ^Halidrys^

^H. osmunda^, the sea-oak. Frond flat, alternately toothed
or indented below; branched apex, bearing air-vessels like
long-stalked pods; substance leathery. Found on the coast of
southern California. (Plate XVI.)

GENUS ^Sargassum^

^Sargassum^ is distinguished by its differentiation into stem and leaf, resembling in outward appearance the higher plants. It [pg074] is a tropical and subtropical genus, and has one hundred and fifty species. Two of these, /S. vulgare/ and /S. Montagnei/, are found as far north as Cape Cod. See Introduction, page 34.

^S. vulgare.^ Stems cylindrical; branches alternate; leaves long,
narrow, toothed, with short stalk and midrib; minute dark spots
on its surface; air-vessels small balls resembling berries set on
stalks and usually tipped with a long point; receptacles small,
twig-like forms in the axils of the leaves; color olive-brown;
plant one foot to three or more feet long. Common in Long Island
Sound. (Plate XVI.)

^S. Montagnei.^ This species resembles /S. vulgare/, but is more
slender in all its parts, and the receptacles are more elongated.
From south of Cape Cod.

^S. bacciferum.^ Particular interest attaches to this species from
the fact that it is the one which forms the floating vegetation
of the Sargasso Sea. It grows attached on the Florida Keys and in
the West Indies. Specimens are sometimes carried by the currents
northward, and are found washed ashore. It differs from /S.
vulgare/ in the leaves, which are thicker, more attenuated, and
sharply toothed, and in having a greater number of air-vessels.
A branch of this species brought from the Sargasso Sea had
air-vessels so numerous and closely set that it resembled a bunch
of small grapes.

III

RED SEAWEEDS

(RHODOPHYCEAE OR FLORIDEAE)

TABLE SHOWING THE CLASSIFICATION OF THE RED SEAWEEDS DESCRIBED IN THIS CHAPTER

Class =ALGAE=

Subclass =Rhodophyceae or Florideae= (/Red Seaweeds/)

Order =NEMALIONACEAE=

Suborders Genera Species

~HELMINTHOCLADIEAE~ ^Nemalion^ ^N. multifidum^
^Liagora^

~CHAETANGIEAE~ ^Scinaia^ ^S. furcellata^

~GELIDIEAE~ ^Gelidium^ ^G. corneum^

Order =GIGARTINACEAE=

^Chondrus^ ^C. crispus^
^Gigartina^ ^G. mamillosa^
^G. radula^
^G. spinosa^
^G. microphylla^
^Phyllophora^ ^P. membranifolia^
^P. Brodiaei^
^Sternogramme^ ^S. interrupta^
^Gymnogongrus^ ^G. Norvegicus^
^Ahnfeldtia^ ^A. plicata^
^Callophyllis^ ^C. variegata^
^C. laciniata^
^Iridaea^

Suborders Genera Species

~RHODOPHYLLIDEAE~ ^Cystoclonium^ ^C. purpurascens^
^C. cirrhosa^
^Euthora^ ^E. cristata^
^Rhodophyllis^ ^R. veprecula^
^Rhabdonia^ ^R. tenera^
^R. Coulteri^
^Eucheuma^ ^E. isiforme^

Order =RHODYMENIACEAE=

~SPHAEROCOCCEAE~ ^Gracilaria^ ^G. multipartita^
^Hypnea^ ^H. musciformis^

~RHODYMENIEAE~ ^Rhodymenia^ ^R. palmata^
^Lomentaria^ ^L. Baileyana^
^Champia^ ^C. parvula^
^Chylocladia^ ^C. articulata^
^Plocamium^ ^P. coccineum^

~DELESSERIEAE~ ^Nitophyllum^ ^N. laceratum^
^N. Ruprechteanum^
^N. punctatum^
^Grinnellia^ ^G. Americana^
^Delesseria^ ^D. sinuosa^
^D. alata^
^D. Leprieurii^

~RHODOMELEAE~ ^Polysiphonia^ ^P. fastigiata^
^P. nigrescens^
^P. parasitica^
^P. dendroidea^
^P. Baileyi^
^P. Harveyi^
^P. Olneyi^
^P. fibrillosa^
^P. violacea^
^P. urceolata^
Var. ^formosa^
^P. variegata^
^P. Woodii^

^Laurencia^ ^L. pinnatifida^
^Dasya^ ^D. elegans^
^D. plumosa^

^Bostrychia^ ^B. rivularis^
^Rhodomela^ ^R. subfusca^
^R. Rochei^
^R. larix^
^R. floccosa^
^Chondria^ ^C. dasyphylla^
^C. tenuissima^
^C. striolata^

Suborders Genera Species

~CERAMIEAE~ ^Callithamnion^ ^C. americanum^
^C. Pylaisaei^
^C. Baileyi^
^C. seirospermum^
^C. byssoideum^
^C. floccosum^
^Griffithsia^ ^G. Bornetiana^
^Ptilota^ ^P. serrata^
^P. elegans^
^P. densa^
^P. hypnoides^
^Spyridia^ ^S. filamentosa^

^Ceramium^ ^C. rubrum^
Var. ^proliferum^
Var. ^secundatum^
^C. strictum^
^C. diaphanum^
^C. fastigiatum^
^C. tenuissimum^
Var. ^patentissimum^
^Microcladia^ ^M. Coulteri^
^M. borealis^

Order =CRYPTONEMIACEAE=

~GLOIOSIPHONIEAE~ ^Gloiosiphonia^ ^G. capillaris^

~GRATELOUPIEAE~ ^Halymenia^ ^H. ligulata^
^Grateloupia^ ^G. Cutleria^
^Prionitis^ ^P. lanceolata^
^P. Andersonii^

~DUMONTIEAE~ ^Pikea^ ^P. Californica^
^Halosaccion^ ^H. ramentaceum^

~RHIZOPHYLLIDEAE~ ^Polyides^ ^P. rotundus^

~SQUAMARIEAE~ ^Peyssonnelia^ ^P. Dubyi^
^Petrocelis^ ^P. cruenta^
^Hildenbrandtia^ ^H. rosea^

~CORALLINEAE~ ^Corallina^ ^C. officinalis^
^Melobesia^

Order =BANGIACEAE=

^Bangia^ ^B. fusco-purpurea^
^Porphyra^ ^P. vulgaris^
^P. laciniata^

[pg079]

RED SEAWEEDS

In =Rhodophyceae=, known also as =Florideae= and =Rhodospermeae=, algae attain their highest development. This is marked by the mode of reproduction, which, more nearly than in the other subclasses, resembles that of flowering plants. The fronds, however, are not as large and do not as closely resemble stem and leaf as do some species of the brown algae.

The species of this subclass are very numerous, and the variety in their fronds, their delicate texture, and their colors, which vary from pink to purple, make them the most attractive of the seaweeds. They grow mostly in deep water, but are often found washed ashore, and many grow just below low-water mark and on the shady side of tide-pools.

In the simplest species the frond consists of branched cell-rows. In some of these the filaments are so fine that a pocket-lens is required to determine the differences in branching and fully to appreciate the beauty of the plant (/Callithamnion/). Some have a cell-surface. In /Delesseria/ the membrane assumes the outline of a foliage-leaf. /Dasya/, which is an abundant variety, is especially beautiful in its feather-like appearance. The corallines are singular in that they are incrusted with lime and resemble corals.

ORDER =NEMALIONACEAE=

SUBORDER ~HELMINTHOCLADIEAE~

GENUS ^Nemalion^

The threadweeds.

^N. multifidum.^ Frond six to twelve inches long, cylindrical,
solid, cord-like, elastic, tough, shiny, very gelatinous; branches
repeatedly in [pg080] a wide-forking manner; sometimes a branch
will divide into several parts at the same point; color dark brown
or purple. It is found, in summer only, from Long Island Sound
northward, growing on smooth rocks which are exposed to the action
of the waves.

GENUS ^Liagora^

Fronds filamentous; branching regularly in a forking manner to the very top, forming thick bunches; slightly incrusted with lime, yet somewhat viscid. It is found in Florida and California, and abounds in tropical waters.

SUBORDER ~CHAETANGIEAE~

GENUS ^Scinaia^

^S. furcellata.^ Frond cylindrical, one eighth of an inch in
diameter, tapering at base, sometimes constricted at intervals,
regularly and several times forked, ending in short divisions;
branches of same length, giving a level top; two to four inches
high; lake-red. When pressed the axis is visible, giving the
appearance of a flat frond with a midrib. This species is found
in summer only, washed ashore from Cape Cod southward and on the
California coast. It is not common. (Plate XVII.)

SUBORDER ~GELIDIEAE~

GENUS ^Gelidium^

^G. corneum.^ Frond flat and horny, one inch to four inches high,
narrow, erect, branched several times in the same plane; ultimate
branchlets club-shaped, or swollen at the tips with masses of
spores; color purple-red. It grows in tufts on mud-covered rocks,
and on algae at low-water mark. The typical form is found in Florida
and on the Pacific coast. Smaller plants are found all along the
Atlantic shore. It is an extremely variable plant, and is often
difficult to distinguish on this account. (Plate XVII.)

ORDER =GIGARTINACEAE=

GENUS ^Chondrus^

Carrageen or Irish moss.

^C. crispus.^ Frond begins with flattened stem, which divides and
subdivides many times in a broad-forked, fan-like manner; varies
greatly in length and breadth of divisions, also in size and color,
according to conditions of its habitation. In shallow tide-pools
it is pale and [pg081] stunted; but under the shelter of
rocks, in deep water, it grows in dense masses and is a dark
purplish-red or reddish-green. Often it appears iridescent when
seen through the water, with the sun shining on it. It is firm and
leathery in substance. It is an edible alga, and was formerly very
generally used for culinary purposes. At Hingham, Massachusetts,
large quantities are gathered as an article of commerce. It is a
beautiful and very common plant found from New York northward.
(Plate XVII.)

GENUS ^Gigartina^

Of the species of this genus but one is found on the eastern coast; on the Pacific coast there are several, and they are large and conspicuous.

^G. mamillosa.^ Frond three to six inches high, one inch to two
inches broad, flat, leathery, gelatinous; forking near the base,
then dividing and subdividing in the same plane; segments more or
less wedge-shaped and with a tendency to roll inward; covered with
numerous small nipple-like protuberances which contain the spores.
These projections distinguish this genus from /Chondrus/, which it
otherwise resembles, and with which it grows. The color is dark
purple. It is found from Boston northward. (Plate XVIII.)

^G. radula.^ Frond flat and thick; rising from a short stem
and widening to several inches; sometimes tapering to the top,
sometimes blunt or divided, sometimes cleft on the sides, but
usually simple; covered with wart-like projections; color dark,
livid red. It is found on the Pacific coast at all seasons, growing
on rocks between tide-marks. Large specimens are one foot to three
feet long and six to ten inches wide. (Plate XVIII.)

^G. spinosa^ ("thorny"). Frond thick, leathery; surface rough and
spiny; form variable, the divisions sometimes emanating from a
broad, flattened base, or again branching from a main axis; all
covered with the protruding processes peculiar to the genus; color
dark red, brown, or purple. It is found on the California coast.
(Plate XVIII.)

^G. microphylla^ ("small-leaved"). Plant rises from short, flat
stem, and rapidly expands into a flat, wide, thin frond which is
simple or divided into two or three segments, each of which tapers
into a long, pointed apex; thickly covered with long, slender
spines, and on its edges bearing small, thin leaflets; color
brownish-red. It is abundant on the California coast. (Plate XVIII.)

GENUS ^Phyllophora^

Leafweed. Fronds cylindrical; branched stalks which expand into rigid, membranaceous, simple or cleft, wedge-shaped laminae; laminae bear leaflets on their edges or on their surface; spores in masses form projections on the surface, or are on stalks at the summit; color dark red. Found washed ashore from New York northward. [pg082]

^P. membranifolia.^ Several stems rise from same disk; branches
expand into wedge-shaped, cleft or forked laminae; lobes bear on the
summit other laminae or leaflets divided in the same manner.

^P. Brodiaei.^ Stem less branched and leaf-expansions broader and
larger than in /P. membranifolia/; laminae wedge-shaped and deeply
lobed. (Plate XIX.)

GENUS ^Sternogramme^

^S. interrupta.^ Frond a thin membrane repeatedly forked, widely
spreading, divisions one fourth to one half of an inch wide;
fertile plants have the spores arranged in an interrupted line
through the center of the segments resembling a midrib; frond two
to eight inches high; bright red. It is found on the California
coast. The illustration shows a plant on which the hydroid
/Sertularia pumila/ is growing. (Plate XIX.)

GENUS ^Gymnogongrus^

^G. Norvegicus.^ Frond two to four inches high, thin but leathery
in substance, flat, narrow, divided in a regular forking manner;
spreading ends of terminal forks obtuse; axils rounded; spores form
spherical masses in the upper segments, and project on both sides
like hemispheres. It resembles a simple form of /Chondrus crispus/,
but is more delicate. The color is red or purple. This species is
found in deep tide-pools from New York northward. (Plate XIX.)

GENUS ^Ahnfeldtia^

^A. plicata.^ Frond coarse, stem-like filaments, stiff, wiry,
irregularly and profusely branched; sometimes regularly forked and
upper segments equal; entangled; six to eight inches long; tufts
several inches in diameter; dark purple or black. Specimens long
exposed on the beach are faded to white. It is very common from New
York northward. (Plate XIX.)

GENUS ^Callophyllis^

^C. variegata.^ Deeply cleft, wide-spreading, flat, membranaceous
frond; all parts notched more or less angularly; color dark to
bright red; spores form hemispherical warts on surface. Some
varieties differ from this one in having long and narrow, and
others in having short and broad segments. It is a beautiful and
common alga on the Pacific coast, resembling /Euthora/ of the
eastern coast. (Plate XX.)

^C. laciniata.^ Frond deeply cleft; segments wedge-shaped. It is
found on the Pacific coast. (Plate XX.)

GENUS ^Iridaea^

Frond rises from stalk and widens into a flat, thick, leathery, oval expansion, one to two feet long, and one to three inches broad; [pg083] simple or lobed; surface sometimes roughened by collections of spores in dots; dark red, often glittering in the water with blue and purple tints. It is found on the Pacific coast. (Plate XX.)

SUBORDER ~RHODOPHYLLIDEAE~

GENUS ^Cystoclonium^

^C. purpurascens.^ The translucent, fleshy, juicy main stem, one
eighth of an inch or less in diameter, runs through the whole
plant; irregularly branched all around main stem; branches again
branch in same manner; branches attenuated at the base, and taper
to a long point; smaller branches distended in places by spores
into bladder-like swellings, hence the name; color rose-red to
dark purple; plants exposed on the beach often faded to orange
and white; six to eighteen inches long. It grows on rocks between
tide-marks as well as in deep water. With the exception of
/Ceramium rubrum/, this is the most common red alga on the eastern
coast from New York northward. It differs from /Rhabdonia/ in
having bladdery branches; otherwise it is easily mistaken for it.

^C. cirrhosa.^ Ends of branches terminate in spirals like tendrils;
otherwise identical with /C. purpurascens/. (Plate XX.)

GENUS ^Euthora^