Chapter V: Part II: Classification of the Species (1)

The following classification is based on the gradual evolution of the fruit from a cone symmetrical in form, parenchymatous in tissue, indehiscent and deciduous at maturity, releasing its wingless seed by disintegration--to a cone oblique in form, very strong and durable in tissue, persistent on the tree, intermittently dehiscent, releasing its winged seeds partly at maturity, partly at indefinite intervals during several years. This evolution embraces two extreme forms of fruit, one the most primitive, the other the most elaborate, among Conifers.

Two sections of the genus, Soft and Hard Pines, are distinguished by several correlated characters, and moreover are distinct by obvious differences in the tissues of their cones as well as in the quality and appearance of their wood.

With the Soft Pines the species group naturally under two subsections on the position of the umbo, the anatomy of the wood and the armature of the conelet. In one subsection (Cembra) are found three species, P. cembra and its allies, with the cone-tissues so completely parenchymatous that the cones cannot release the seeds except by disintegration. In both subsections there is a gradual evolution from a wingless nut to one with an effective wing, adnate in one subsection, adnate and articulate in the other. The different stages of this evolution are so distinct that the Soft Pines are easily separated into definite groups.

Among the Hard Pines a few species show characters that are peculiar to the Soft Pines. These exceptional species form a subsection (Parapinaster) by themselves.

With the remaining species, the majority of the Pines, the distinctions that obtain among Soft Pines have disappeared. The dorsal umbo, the articulate seed-wing, the persistent fascicle-sheath, the dorsal and ventral stomata of the leaf and its serrate margins, the dentate walls of the ray-tracheids have become fixed and constant. But a new form of seed-wing appears, with a thickened blade, assuming such proportions in P. Sabiniana and its two allies that these three constitute a distinct group, remarkable also for the size of its cones.

Here also appear a new form of fruit, the oblique cone, and a new method of dissemination, the serotinous cone. Associated with the latter are the persistent cone and the multinodal spring-shoot. These characters do not develop in such perfect sequence and regularity that they can be employed for grouping the species without forcing some of them into unnatural association. The oblique cone first appears sporadically here and there and without obvious reason. The persistent cone, the first stage of the serotinous cone, is equally sporadic in the earlier stages of evolution. The same may be said of the multinodal shoot.

Nevertheless these characters show an obvious progression toward a definite goal, where they are all united in a small group of species remarkable for the form and texture of their cones, for a peculiar seed-release and for the vigor and rapidity of their growth. It is possible, with the assistance of other characters, to segregate these species in three groups in which the affinities are respected and the general trend of their evolution is preserved.

The first group, the Lariciones, contains species with large ray-pits, cones dehiscent at maturity, and uninodal spring-shoots. They are, with two exceptions, P. resinosa and P. tropicalis, Old World species.

The second group, the Australes, contains species with small ray-pits, cones dehiscent at maturity and spring-shoots gradually changing, among the species, from a uninodal to a multinodal form. They are, without exception, species of the New World.

The third group, the Insignes, contains the serotinous species. The ray-pits are small and the spring-shoots are, with two exceptions, multinodal. With two exceptions, P. halepensis and P. pinaster, they are New World species.

These three groups, being the progressive sequence of a lineal evolution, are not absolutely circumscribed, but are more or less connected through a few intermediate species of each group. The systematic position of these intermediate species is determined by their obvious affinities. It cannot be expected that the variations, which take an important part in the evolution of the species, progress with equal step or in perfect correlation with each other.

As to specific determinations, a little experience in the field discloses an amount of variation in species that does not always appear in the descriptions of authors; and species that are under the closest scrutiny of botanists, foresters or horticulturalists, attest by their multiple synonymy their wide variation. The possibilities of variation are indefinite and, with adaptable Pines, the range of variation is somewhat proportionate to change of climate. In mountainous countries, where there are warm sheltered valleys with rich soil below cold barren ledges, the most variable Pines are found. The western species of North America, for instance, are much more variable than the eastern species, while in Mexico, a tropical country with snow-capped mountains, the variation is greatest.

Therefore in the limitation of species undue importance should not be given to characters responsive to environment, such as the dimensions of leaf or cone, the number of leaves in the fascicle, etc. Moreover, there are familiar examples (P. sylvestris, etc.) that show the possibility of wide differences in the cone of the same species.

In the following classification species only are considered without attempting to determine varietal or other subspecific forms. But varieties are often mentioned as one of the factors illustrating the scope of species. Synonymy serves a like purpose, but synonyms not conveying useful information are omitted, Roezl's list of Mexican species, for instance, and variations in the orthography of specific names.

PINUS

1755 Pinus Duhamel, Traite des Arbres, ii. 121.
1790 Apinus Necker, Elem. Bot. iii. 269.
1852 Cembra Opiz, Seznam, 27.
1854 Strobus Opiz, Lotos, iv. 94.
1903 Caryopitys Small, Fl. Southeast. U. S. 29.

Leaves and shoots dimorphous, primary leaves on long shoots, secondary leaves on dwarf shoots. Flowers diclinous, the pistillate taking the place of long shoots, the staminate taking the place of dwarf shoots. Growth of wood and fruit emanating from the nodes; buds, branchlets and cones, therefore, in verticillate association. Leaves and staminate flowers in internodal position, the primary leaves along the whole length of the internode, subtending secondary leaf-fascicles on the apical, staminate flowers on the basal part. Buds compounded of minute buds in the axils of bud-scales, becoming the bracts of the spring-shoot. Branchlets of one or more internodes, each internode in three parts--a length without leaves, a length bearing leaves and a node of buds. Cone requiring two, rarely three years to mature, displaying its annual growths by distinct areas on each scale. Seeds wingless or winged, edible and nutritious.

The Pines are confined to the northern hemisphere, but grow in all climates and under all conditions of soil, temperature and humidity where trees can grow. Some of the species are of very restricted range, but others are adaptable and can cover wide areas. The sixty-six species are distributed as follows--

Eastern Hemisphere, 23.

1 exclusively African (Canary Islands).
2 exclusively European.
3 about the Mediterranean Basin.
2 common to Europe and northern Asia.
14 exclusively Asiatic.

Western Hemisphere, 43.

28 in western North America, of which 12 are confined to Mexico
and Central America.
15 in eastern North America, of which 2 are exclusively West Indian.

The two sections of the genus correspond with those of Koehne (Deutsch. Dendrol. 28 [1893]) and his two names, Haploxylon and Diploxylon, are adopted here, together with his two subsections of Haploxylon, Cembra and Paracembra.

Of the two subsections of Diploxylon, Pinaster has been employed by Endlicher (Syn. Conif. 166 [1847]) and later authors for smaller or larger groups of Hard Pines. The subsection Parapinaster is now proposed.

The names of groups, Cembrae, Strobi, Cembroides, Gerardianae, Balfourianae, Pineae, Lariciones and Australes, are taken from Engelmann's Revision of the Genus Pinus (Trans. Acad. Sci. St. Louis, iv. 175-178 [1880]). The remainder, Flexiles, Leiophyllae, Longifoliae, Insignes and Macrocarpae, are here proposed.

In order to bring the illustrations within the limits of the page the dimensions of cone and leaf, as shown on the plates, are a little smaller than life. In plates X and XXV the reproductions of the cones are reduced to 2/5 life-size.

SECTIONS, SUBSECTIONS, AND GROUPS

Bases of the fascicle-bracts non-decurrent A--HAPLOXYLON

Umbo of the cone-scale terminal a--Cembra

Seeds wingless.
Cones indehiscent I. Cembrae
Cones dehiscent II. Flexiles
Seed with an adnate wing III. Strobi

Umbo of the cone-scale dorsal b--Paracembra

Seeds wingless IV. Cembroides
Seed-wing short, ineffective V. Gerardianae
Seed-wing long, effective VI. Balfourianae

Bases of the fascicle-bracts decurrent B--DIPLOXYLON

Fascicle-sheath or seed of Haploxylon c--Parapinaster

Fascicle-sheath deciduous VII. Leiophyllae
Fascicle-sheath persistent.
Seed-wing of the Strobi VIII. Longifoliae
Seed-wing of the Gerardianae IX. Pineae

Fascicle-sheath persistent, seed-wing
articulate, effective d--Pinaster

Base of wing-blade thin or slightly
thickened.
Cones dehiscent at maturity.
Pits of ray-cells large X. Lariciones
Pits of ray-cells small XI. Australes
Cones serotinous, pits of ray-cells small XII. Insignes
Base of wing-blade very thick XIII. Macrocarpae

HAPLOXYLON

Bases of the bracts subtending leaf-fascicles not decurrent. Staminate flowers not sufficiently developed in the bud to be apparent. Spring-shoots uninodal. Fibro-vascular bundle of the leaf single. Cone symmetrical, of relatively fewer larger scales, its tissues softer. Bark-formation late, the trunks of young trees smooth. Wood soft and with little resin, of uniform color and with relatively obscure definition of the annual rings. Tracheids of the medullary rays with smooth walls.

All the species of this section, except P. Nelsonii, have deciduous
fascicle-sheaths. There are but two species of Diploxylon with
deciduous sheaths, P. leiophylla and P. Lumholtzii, both of them
easily recognized. The deciduous sheath, therefore, is an obvious and
useful means for recognizing the Soft Pines. On the characters of the
fruit and the wood Haploxylon can be divided into two subsections.

a. Cembra Umbo of the cone-scale terminal.
b. Paracembra Umbo of the cone-scale dorsal.

=Cembra=

Umbo of the cone-scale terminal. Scales of the conelet unarmed. Leaves in fascicles of 5, the sheath deciduous, the two dermal tissues distinct, the hypoderm-cells uniform. Pits of the cells of the wood-rays large.

Seeds wingless.
Cones indehiscent I. Cembrae.
Cones dehiscent II. Flexiles.
Seeds with an adnate wing III. Strobi.

=I. CEMBRAE=

Seeds wingless. Cones indehiscent, deciduous at maturity.

In this group of species there is no segregation of sclerenchyma into
an effective tissue. The cones are inert under hygrometric changes and
may always be recognized in herbaria by their persistent occlusion and
soft tissues. The seeds are released only by the disintegration of the
fallen cone. There is, however, a vicarious dissemination by predatory
crows (genus Nucifraga) and rodents.

Leaves serrulate, their stomata ventral only.
Cones relatively larger, the apophyses protuberant 1. koraiensis.
Cones relatively smaller, the apophyses appressed 2. cembra.
Leaves entire, their stomata ventral and dorsal 3. albicaulis.

1. PINUS KORAIENSIS

1784 P. strobus Thunberg, Fl. Jap. 275 (not Linnaeus).
1842 P. koraiensis Siebold & Zuccarini, Fl. Jap. ii. 38.
1857 P. mandschurica Ruprecht in Bull. Acad. Sci. St. Petersb. xv. 382.

Spring-shoots more or less densely tomentose. Leaves from 8 to 12 cm. long, serrulate, stomata ventral only, resin-ducts medial and confined to the angles. Conelets large, subterminal, or on young trees often pseudolateral. Cones indehiscent, from 9 to 14 cm. long, short-pedunculate, ovoid-conical or subcylindrical; apophyses dull pale nut-brown, rugose, shrinking much in drying and exposing the seeds, prolonged and tapering to a more or less reflexed tip, the umbo inconspicuous; seeds large, wingless, the spermoderm entire.

A species of the mountains of northeastern Asia with valuable wood and
large edible nuts; hardy and often cultivated in cool-temperate
climates.

The P. koraiensis of Beissner (in Nuov. Giorn. Bot. Ital. n. ser. iv.
184) and of Masters (in Gard. Chron. ser. 3, xxxiii. 34, ff.) are P.
Armandi and have led to an erroneous extension of the range of this
species into Shensi and Hupeh. In the original description of the
species the authors call attention to an error in the plate, where a
cone of another species has been substituted.

P. koraiensis resembles P. cembra in leaf and branchlet but not in the
cone. It is often confused with P. Armandi, but can easily be
distinguished by its tomentose branchlets, indehiscent cone and
peculiar seed. The two species, moreover, do not always agree in the
position of the foliar resin-ducts.

Plate VIII.

Fig. 85, Cone and seed. Fig. 86, Leaf-fascicle and magnified
leaf-section.

2. PINUS CEMBRA

1753 P. cembra Linnaeus, Sp. Pl. 1000.
1778 P. montana Lamarck, Fl. Franc. iii. 651 (not Miller).
1858 P. pumila Regel in Index Sem. Hort. Petrop. 23.
1884 P. mandschurica Lawson, Pinet. Brit. i. 61, ff. (not Ruprecht).
1906 P. sibirica Mayr, Fremdl. Wald- & Parkb. 388.
1913 P. coronans Litvinof in Trav. Mus. Bot. Acad. St. Petersb.
xi. 23, f.

Spring-shoots densely tomentose. Leaves from 5 to 12 cm. long, serrulate; stomata ventral only; resin-ducts medial or, in the dwarf form, often external. Conelets short-pedunculate, purple during their second season. Cone from 5 to 8 cm. long, ovate or subglobose, subsessile; apophyses dull nut-brown, thick, slightly convex, the margin often a little reflexed, the umbo inconspicuous; seeds wingless, large, the dorsal spermoderm adnate partly to the nut, partly to the cone-scale, the ventral spermoderm wanting.

The Swiss Stone Pine attains a height of 15 or 25 metres and occupies
two distinct areas, the Alps, from Savoy to the Carpathians at high
altitudes, and the plains and mountain-slopes throughout the vast area
from northeastern Russia through Siberia. Beyond the Lena and Lake
Baikal it becomes a dwarf (var. pumila) with its eastern limit in
northern Nippon and in Kamchatka. It is successfully cultivated in the
cool-temperate climates of Europe and America. The wood is of even,
close grain, peculiarly adapted to carving. The nuts are gathered for
food and confections, but are destroyed in great numbers by squirrels,
mice and a jay-like crow, the European Nutcracker. It is generally
conceded, however, that these enemies assist in dissemination.

Plate VIII.

Fig. 87, Cone, seed and magnified leaf-section. Fig. 88, Tree at
Arolla, Switzerland. Fig. 89, Cone, leaf-fascicle and magnified
leaf-section of var. pumila.

3. PINUS ALBICAULIS

1853 P. flexilis Balfour in Bot. Exped. Oregon, 1, f. (not James).
1857 P. cembroides Newberry in Pacif. R. R. Rep. vi-3, 44, f.
(not Zuccarini).
1863 P. albicaulis Engelmann in Trans. Acad. Sci. St. Louis, ii. 209.
1867 P. shasta Carriere, Trait. Conif. ed. 2, 390.

Spring-shoots glabrous or pubescent. Branchlets pliant and tough. Leaves from 4 to 7 cm. long, entire, stout, persistent for several years; stomata dorsal and ventral; resin-ducts external. Conelets short-pedunculate, dark purple during the second season, their scales often tapering to an acute apex. Cones from 5 to 7 cm. long, subsessile, oval or subglobose; apophyses nut-brown or fulvous brown, dull or slightly lustrous, very thick, the under surface conspicuous, meeting the upper surface in an acute margin, and terminated by a salient, often acute umbo; seed wingless, the testa bare of spermoderm.

This species ranges from British Columbia through Washington and
Oregon, over the mountains of northern California and the Sierras as
far south as Mt. Whitney, and, on the Rocky Mountains, through Idaho
and Montana to northern Wyoming. It is found at the timber-line of
many stations and forms, in exposed situations, flat table-like masses
close to the ground. It is a species of no economical importance and
is too inaccessible for the profitable gathering of its large nuts,
which are devoured in quantity by squirrels and by Clark's crow, a
bird of the same genus with the pinivorous Nutcracker of Europe.

P. albicaulis is distinguished from its allies by its entire leaves
with both dorsal and ventral stomata, from P. flexilis by its
indehiscent cone, and from all of these species by its seed without
membranous cover or rudimentary wing. It was united with P. flexilis
by Parlatore and Gordon, and, later, was referred to that species as a
varietal form by Engelmann (in Brewer & Watson, Bot. Calif. ii. 124).
Parrish's P. albicaulis (in Zoe, iv. 350), extending its range to the
mountains of southern California, proves to be P. flexilis (Jepson,
Silva Calif. 74).

Plate VIII.

Fig. 90, Two cones and seed. Fig. 91, Leaf-fascicle. Fig. 92,
Magnified leaf-section.

=II. FLEXILES=

Seeds wingless, the spermoderm forming a narrow border with a rudimentary prolongation. Cones dehiscent at maturity.

The dehiscent cone distinguishes this group from the Cembrae.
Therefore confusion of P. koraiensis with P. Armandi, or P. albicaulis
with P. flexilis should be impossible. The peculiar seed is found
again only in the northern variety of P. ayacahuite.

Leaves usually entire, the stomata dorsal and ventral 4. flexilis.
Leaves serrulate, the stomata ventral only 5. Armandi.

4. PINUS FLEXILIS

1823 P. flexilis James in Long's Exped. ii. 34.
1882 P. reflexa Engelmann in Bot. Gaz. vii. 4.
1897 P. strobiformis Sargent, Silva N. Am. xi. 33, tt. 544, 545
(not Engelmann).

Spring-shoots pubescent; branchlets very tough and pliant. Leaves from 3 to 9 cm. long, entire, or serrulate in the southern variety, persistent for five or six years; stomata dorsal and ventral or, in the south, sometimes ventral only; resin-ducts external. Cones from 6 to 25 cm. long, ovate or subcylindrical, short-pedunculate; apophyses pale tawny yellow, or yellow ochre, lustrous, often prolonged and more or less reflexed, thick, the margin together with the umbo raised above the surface of the cone.

This species grows on the Rocky Mountains from Alberta in the Dominion
of Canada to Chihuahua in northern Mexico and ranges westward to the
eastern slope of the Sierras and to the southern mountains of
California. The wood, where accessible, is manufactured into lumber.
It may be seen in the Arnold Arboretum and in the Royal Gardens at
Kew.

P. flexilis is recognized by its lustrous yellow cones. This and the
constantly external ducts of its usually entire leaves distinguish it
from P. Armandi. From P. albicaulis, with similar leaves, it differs
by its dehiscent cone. At one extreme the cone of P. flexilis is not
unlike that of P. albicaulis, at the other extreme it approaches the
characteristic cone of P. ayacahuite, with prolonged reflexed scales.
Hence the confusion of P. albicaulis with P. flexilis (Murray,
Parlatore and others) and of P. flexilis with Engelmann's P.
strobiformis. Sargent's P. strobiformis, illustrated in the Silva of
North America, is the form of this species known as var. reflexa of
Engelmann.

Plate IX.

Fig. 93, Two cones and seed. Fig. 94, Leaf-fascicle. Fig. 95,
Magnified leaf-section.

5. PINUS ARMANDI

1884 P. Armandi Franchet in Nouv. Arch. Mus. Paris, ser. 2,
vii. 95, 96, t. 12.
1898 P. scipioniformis Masters in Bull. Herb. Boiss. vi. 270.
1903 P. koraiensis Masters in Gard. Chron. ser. 3, xxxiii. 34,
ff. 18, 19 (not Siebold & Zuccarini).
1908 P. Mastersiana Hayata in Gard. Chron. ser. 3, xliii, 194.

Spring-shoots glabrous; branches and most of the trunk covered with a smooth gray cortex. Leaves from 8 to 15 cm. long, serrulate; stomata ventral only; resin-ducts external, external and medial, or medial, all three conditions sometimes occurring in leaves of the same branchlet. Cones from 6 to 20 cm. in length, pendent on peduncles of various lengths, the peduncle often remaining on the tree after the fall of the cone; apophyses fulvous brown, dull or sublustrous, the margin rounded or tapering to an acute apex, sometimes a little prolonged and reflexed, the umbo inconspicuous.

A tree of the mountains of central, southern and western China with an
outlying station on the Island of Formosa. Recently planted in Europe
and America, it has so far proved hardy. The nuts are gathered for
food and some use is made of the wood.

The glabrous shoots of P. Armandi distinguish it from P. flexilis and
P. koraiensis. From the latter it is also distinct in its dehiscent
cone and in its seed. The section of its leaf, with dorsal ducts often
in two positions, is peculiar to this species among Soft Pines.

Plate IX.

Fig. 96, Two cones and seed. Fig. 97, Leaf-fascicle. Figs. 98, 99,
Magnified sections of three leaves.

=III. STROBI=

Seed with a long effective wing adnate to the nut.

The base of the seed-wing corresponds to the marginal spermoderm of the Flexiles but is prolonged into an effective adnate wing. This form of wing appears again in the species Balfouriana and in the group Longifoliae.

Cones very long, usually exceeding 25 cm.
Cone-scales prolonged and reflexed 6. ayacahuite.
Cone-scales appressed 7. Lambertiana.
Cones less than 25 cm. long.
Cone-scales prominently convex.
Leaves less than 7 cm. long 8. parviflora.
Leaves 9-12 cm. long 9. peuce.
Leaves 12-18 cm. long 10. excelsa.
Cone-scales thin, conforming to the surface of
the cone.
Cone relatively longer, its phyllotaxis 8/21 11. monticola.
Cone relatively shorter, its phyllotaxis 5/13 12. strobus.

6. PINUS AYACAHUITE

1838 P. ayacahuite Ehrenberg in Linnaea, xii. 492.
1848 P. strobiformis Engelmann in Wislizenus, Tour Mex. 102.
1857 P. Veitchii Roezl, Cat. Graines Conif. Mex. 32.
1858 P. Bonapartea Roezl in Gard. Chron. 358.
1858 P. Loudoniana Gordon, Pinet. 230.

Spring-shoots glabrous or pubescent. Leaves from 10 to 20 cm. long, serrulate, their stomata ventral only, their resin-ducts external, often numerous. Cones from 25 to 45 cm. long, pendent on long stalks, subcylindrical or tapering, often curved; apophyses pale nut-brown, dull or sublustrous, varying much in thickness, prolonged in various degrees, the prolongations patulous, reflexed, recurved or revolute; seeds of the southern typical form with a long wing, the wing diminishing and the nut increasing in relative size northward.

The White Pine of Mexico and Guatemala grows on mountain-slopes and at
the head of ravines. It is not very hardy in cultivation except in the
milder parts of Great Britain and in northern Italy, where the forms
of central and northern Mexico have been very successful. The species
is best recognized by the prolonged apophyses of its large cone.

The variations in the size of the cone and in the prolongations of its
scales are many, but of far more significance is the remarkable
variation of the seed-wing, which is long in the southern part of the
range, short and broad in central Mexico, and rudimentary, like the
seed of P. flexilis, in the north. This makes it possible to establish
two well defined varieties--Veitchii and brachyptera. The three forms
of the species present a gradation from the long effective wing of the
Strobi to the rudimentary form of the Flexiles. Many of the seed-wings
of the var. Veitchii correspond, in their short broad form and opaque
coloring, with the characteristic wing of P. Lambertiana.

Plate X. (leaves and cones much reduced).

Fig. 103, Cone and cone-scale of var. Veitchii. Fig. 104, Cone and
seed of var. brachyptera. Fig. 105, Cone-scale of the typical form.
Figs. 106, 107, Leaf-fascicles and magnified leaf-sections.

7. PINUS LAMBERTIANA

1827 P. Lambertiana Douglas in Trans. Linn. Soc. xv. 497.

Spring-shoots pubescent. Leaves from 7 to 10 cm. long, serrulate; stomata dorsal and ventral; resin-ducts external or with one or two ventral medial ducts. Cones from 30 to 50 cm. long, pendent, subcylindrical, tapering to a rounded apex; apophyses pale nut-brown, thick, a narrow border of the under surface showing on the closed cone, the margin rounded or tapering to a blunt slightly reflexed tip; seed with a large nut and a broad short opaque wing.

The Sugar Pine is the tallest of the genus and attains a height of 50
or 60 metres. It grows on mountain slopes and the sides of ravines.
Its southern limit is in Lower California on the plateau of San Pedro
Martir, its northern limit is in western Oregon. The wood is valuable,
its nuts are eaten by native Indians, and the sweet exudation, which
gives the tree its popular name, is a manna-like substance of some
officinal value. P. Lambertiana is recognized by its long cone and by
the constant dorsal stomata of its leaves.

Plate X. (leaves and cone much reduced).

Fig. 100, Cone and seed. Fig. 101, Conelet. Fig. 102, Leaf-fascicle
and magnified leaf-section.

8. PINUS PARVIFLORA

1784 P. cembra Thunberg, Fl. Jap. 274. (not Linnaeus).
1842 P. parviflora Siebold and Zuccarini, Fl. Jap. ii. 27, t. 115.
1890 P. pentaphylla Mayr, Mon. Abiet. Jap. 78, 94, t. 6.
1908 P. morrisonicola Hayata in Gard. Chron. ser. 3, xliii. 194.
1908 P. formosana Hayata in Jour. Linn. Soc. xxxviii. 297, t. 22.

Spring-shoots pubescent or glabrous; branches becoming studded with prominent resin-cells of the cortex. Leaves from 3 to 8 cm. long, slender, serrulate; stomata ventral only; resin-ducts external and dorsal. Cones subsessile, often persistent, from 5 to 10 cm. long, patulous or horizontal, short-ovate, or elongate and slightly conical; apophyses nut-brown, abruptly convex near the apex, or irregularly warped, varying much in size, the umbo confluent with the thin margin of the scale and resting on the apophysis beneath; seeds with a large nut and a short broad wing, often temporarily adherent to the cone-scale and breaking apart at the fall of the nut.

A tree of the mountains of Japan and Formosa, cultivated extensively.
It is recognized by its very short quinate leaves and by its nearly
sessile cones. The frequent but not invariable retention of the
seed-wing in the cone is due to adhesion. Many seeds fall with their
wings intact, others break away from the wing which, after a while,
loosens and also falls.

Plate XI.

Figs. 114, 115, Three cones and seed. Fig. 116, Leaf-fascicle and
magnified leaf-section.

9. PINUS PEUCE

1844 P. peuce Grisebach, Spicil. Fl. Rumel. ii. 349.
1865 P. excelsa Hooker in Jour. Linn. Soc. viii. 145. (not Wallich).

Spring-shoots glabrous. Leaves from 7 to 10 cm. long, erect, serrulate; stomata ventral only; resin-ducts external. Connective of pollen-sacs small and narrow. Cones deciduous, from 8 to 15 cm. long, subcylindrical, often curved, the peduncle short; apophyses tawny yellow, prominently and abruptly convex, the umbo against the scale beneath; seed-wing long.

A tree of the Balkan Mountains, very hardy and bearing abundant fruit
in the gardens of both hemispheres. The cone resembles that of P.
excelsa, but is prevalently much shorter and with a relatively shorter
peduncle. Its leaves are also much shorter and are always erect. A
curious difference is found in the connectives of the pollen-sacs,
small in peuce (fig. 113), large in excelsa (fig. 110). The convexity
of its apophyses distinguishes the cone from those of P. monticola and
P. strobus. Beissner followed Hooker and named this species excelsa,
var. peuce, in the first edition of his Handbuch (1891), but in the
second edition he restored the Balkan Pine to specific standing.

Plate XI.

Fig. 111, Cone and seed. Fig. 112, Leaf-fascicle and magnified
leaf-section. Fig. 113, Pollen-sacs and connective magnified.

10. PINUS EXCELSA

1824 P. excelsa Wallich ex Lambert, Gen. Pin. ii, 5, t. 3.
1845 P. nepalensis De Chambray, Arbr. Resin. 342.
1854 P. Griffithii McClelland in Griffith, Notul. Pl. Asiat. iv, 17;
Icon. Pl. Asiat. t. 365.

Spring-shoots glabrous. Leaves from 10 to 18 cm. long, drooping, serrulate; stomata ventral only; resin-ducts external but often with a medial ventral duct. Connective of the pollen-sacs large. Cones from 15 to 25 cm. long, narrow-cylindrical; apophyses tawny yellow or pale fulvous brown, prominently convex, the umbo against the apophysis beneath; seeds with a long wing.

A tree with gray-green drooping foliage, found, with some
interruptions, along the Himalayas. It furnishes resin, tar and wood
of considerable value. It is cultivated in all temperate climates and
is a familiar tree of American and European gardens. Madden states
that the foliage of P. excelsa is sometimes erect and is occasionally
bright green. Such variations are often met in other species of Pinus.
Usually the drooping gray-green foliage and the peculiar cone are
sufficient for the recognition of this species. The not infrequent
presence of a medial duct and the large connective are valuable aids
for identifying it.

Plate XI.

Fig. 108, Cone and seed. Fig. 109, Leaf-fascicle and magnified
section of two leaves. Fig. 110, Pollen-sacs and connective
magnified.

11. PINUS MONTICOLA

1837 P. monticola Douglas ex Lambert, Gen. Pin. iii. t.
1884 P. porphyrocarpa Lawson, Pinet. Brit. i, 83, ff.

Spring-shouts pubescent. Leaves from 4 to 10 cm. long, serrulate; stomata ventral or rarely with a few dorsal stomata; resin-ducts external. Cones from 10 to 25 cm. long, cylindrical or tapering, sometimes curved; apophyses brown-ochre or fulvous brown, thin, smooth, conforming to the surface of the cone, the apex sometimes slightly prolonged and reflexed, the umbo not quite touching the surface of the scale below.

The western White Pine grows in southern British Columbia and on
Vancouver Island, on the Rocky Mountains of Montana and Idaho, in
Washington, on the Blue Mountains, Cascades and Coast Range of Oregon,
across northern California and along the Sierras to the mountains of
southern California. Where it is abundant and accessible it furnishes
valuable timber. It is hardy in New England and in northern and
central Europe.

It differs from P. strobus in the higher phyllotaxis of its cone, an
obvious difference that may be seen by comparing cones of the two
species of the same length (figs. 117, 119), the number of scales on
the cone of P. monticola being much greater than that on the cone of
P. strobus. Nuttall (Sylva, iii, 118) followed Hooker in considering
it to be a variety of P. strobus.

Plate XII.

Fig. 117, Cone and cone-scale. Fig. 118, Leaf-fascicle and magnified
leaf-section.

12. PINUS STROBUS

1753 P. strobus Linnaeus, Sp. Pl. 1001.
1855 P. nivea Booth ex Carriere, Trait. Conif. 305.
1862 P. alba-canadensis Provancher, Fl. Canad. ii. 554.
1903 Strobus strobus Small, Fl. Southeast. U. S. 29.

Spring-shoots pubescent. Leaves from 6 to 14 cm. long, serrulate; stomata ventral only; resin-ducts external. Cones from 8 to 24 cm. long, narrow cylindrical, sometimes curved; apophyses fulvous brown, or rufous brown, thin, the smooth or slightly rugose surface conforming to the general surface of the cone; seed with a long wing.

A valuable timber-tree of singular beauty and rapid growth. The
northern limit of its range extends from Newfoundland to Manitoba; it
grows throughout the northern states from Minnesota to the Atlantic,
and, south of Pennsylvania, along the Appalachians to northern
Georgia. Its tractable and reliable wood, its adaptability to various
soils and climates, its early maturity and stately habit, recommend it
to the forester and gardener.

Mature trees of P. strobus tower above the evergreens associated with
it. It is also recognized by the color and horizontal massing of its
foliage. The cone, when closed, is very narrow; its thin flat scales
distinguish it from the cone of P. peuce, and its phyllotaxis from the
cone of P. monticola. To illustrate the possibilities of variation in
the size of Pine cones, I once collected several in Tamworth, N. H.,
on the estate of Mr. Augustus Hemenway, on the same slope and within
an area of one square kilometre. These cones varied in length from 6
to 24 cm., with all intermediate sizes. Also on each tree were cones
of various lengths, but the longest were confined to two or three
trees among the several hundred examined. Dimensions of leaves also
varied with individual trees; not infrequently the leaves of a tree
were twice the length of those of an adjacent tree. Such variations
appear in many species and in many localities.

Plate XII.

Fig. 119, Two cones. Fig. 120, Leaf-fascicle. Fig. 121, Magnified
leaf-section. Fig. 122, Conelets. Fig. 123, A cultivated tree in
Massachusetts.

=Paracembra=

Umbo of the cone-scale dorsal. Scales of the conelet mucronate or aristate. Epiderm and hypoderm of the leaf similar, appearing as a single tissue; resin-ducts external. Pits of the ray-cells small.

The wood of this subsection differs from that of other species, except
that of P. pinea, in the Picea-like characters of the medullary
rays--tracheids with smooth walls combined with the thick walls and
small pits of the ray-cells. On the character of the seeds the species
may be divided into three groups.

Seeds wingless IV. Cembroides.
Seeds with a short, ineffective, articulate wing V. Gerardianae.
Seeds with a long and effective wing VI. Balfourianae.

=IV. CEMBROIDES=

Seeds wingless, the nut large, wholly or partly bare of membranous cover. Cones varying from yellow-ochre to deep red-orange in color.

These are the Nut Pines, growing on the arid slopes and table-lands
above the great plateau of northern Mexico and its extension into the
southwestern United States. There are three distinct species.

Leaves entire, the sheath deciduous.
Cones subglobose, subsessile 13. cembroides.
Cones cylindrical, pedunculate 14. Pinceana.
Leaves serrulate, the sheath persistent 15. Nelsonii.

13. PINUS CEMBROIDES

1832 P. cembroides Zuccarini in Abh. Akad. Muench. i. 392.
1838 P. Llaveana Schiede in Linnaea, xii. 488.
1845 P. monophylla Torrey in Fremont's Rep. 319, t. 4.
1847 P. Fremontiana Endlicher, Syn. Conif. 183.
1848 P. edulis Engelmann in Wislizenus, Tour. Mex. 88.
1848 P. osteosperma Engelmann in Wislizenus, Tour. Mex. 89.
1862 P. Parryana Engelmann in Am. Jour. Sci. ser. 2, xxxiv. 332
(not Gordon).
1897 P. quadrifolia Sudworth, Bull. 14, U. S. Dep. Agric. 17.
1903 Caryopitys edulus Small, Fl. Southeast. U. S. 29.

Spring-shoots pruinose. Leaves from 2 to 6 cm. long, in fascicles of 1 to 5, the sheath-scales revolute at the apex, then deciduous; stomata ventral, or ventral and dorsal; resin-ducts external. Scales of the conelet armed with a minute prickle. Cones from 4 to 6 cm. long, subglobose, subsessile; apophyses lustrous ochre-yellow, crowned with a quadrilateral umbo bearing the minute prickle of the conelet; seed flaxen yellow when fresh, its testa bare, the spermoderm adnate to the cone-scale.

A broad tree with a round head, similar in size and form, but not in
ramification, to the cultivated Apple-tree; growing on arid slopes and
table-lands. Its eastern limit is in southwestern Wyoming, central
Colorado, Texas, western Tamaulipas and northwestern Vera Cruz. It
ranges over Utah, Nevada, Arizona and the northern states of Mexico to
the southern Sierras of California and to the northern and southern
extremities of Lower California. It is recognized by its small cone,
which expands, when open, into an irregular flat aggregate of loosely
attached scales. The leaves are shorter than those of the other Pines
of this group.

The cone of this species always retains its peculiar character. The
variations are mainly in the number of leaves in the fascicle. On this
character this Nut Pine is divided by many authors into four
species--cembroides, with three slender leaves--edulis, with two stout
leaves--monophylla, with one leaf and--Parryana, with four stout
leaves. But there are intermediate forms that may be either cembroides
or edulis, edulis or monophylla etc., and Voss's reduction of the four
to a single species with three varieties seems to be justified (Mitt.
Deutsch. Dendrol. Ges. xvi. 95).

Plate XIII.

Fig. 130, Cone, cone-scale and seed. Fig. 131, Open cone. Fig. 132,
Branchlet with leaves and magnified leaf-section.

14. PINUS PINCEANA

1846 P. cembroides Gordon in Jour. Hort. Soc. Lond. i. 236, f.
(not Zuccarini).
1858 P. Pinceana Gordon, Pinet. 204.
1882 P. latisquama Engelmann in Gard. Chron. ser. 2, xviii. 712.
f. 125 (as to cone only).

Spring-shoots slender, pruinose. Leaves in fascicles of three, the sheath revolute at the base, then deciduous; stomata ventral, or ventral and dorsal; resin-ducts external. Scales of the conelet minutely mucronate. Cones from 6 to 9 cm. long, cylindrical, pendent on long peduncles; apophyses lustrous ochre-yellow, elevated in the centre, the umbo usually retaining the small prickle; seed large, bearing on its dorsal surface remnants of the spermoderm.

A small bushy tree with long slender branchlets, clear gray cortex,
persistently smooth except on the lower part of the trunk, and
glaucous-green foliage. It grows along water-courses, dry in autumn
and winter, from southern Coahuila to central Hidalgo, and is
associated with P. cembroides, from which it may be distinguished by
its longer leaves and much longer cylindrical cone.

Plate XIII.

Fig. 127, Cone, cone-scale and seed. Fig. 128, Branchlet with
leaves. Fig. 129, Magnified leaf-section.

15. PINUS NELSONII

1904 P. Nelsonii Shaw in Gard. Chron. ser. 3, xxxvi. 122, f. 49.

Spring-shoots slender, pruinose; branchlets very pliant and tough, summer-shoots abundant. Leaves with a persistent sheath, from 6 to 9 cm. long, united in threes along a portion of their ventral surface into pseudomonophyllous fascicles, serrulate on the two margins of the dorsal surface, entire on the ventral margin; stomata dorsal and with one row along the free portion of each ventral face. Conelets usually, if not always, pseudolateral by reason of the summer growth of the branchlets, and attaining in their first season an unusually large size. Cones from 6 to 12 cm. long, on very long stout and curved peduncles, cylindrical, deciduous by an articulation between the cone and its peduncle, leaving the latter for several years on the tree; apophyses dark lustrous orange-red, rugose, elevated along a sharp transverse keel, the umbo obscurely defined, the mucro usually broken away; nuts large, flaxen yellow, the spermoderm adnate to the cone-scale.

A small bushy tree with long pliant branches, clear gray cortex all
over the limbs and trunk, and sparse gray-green foliage. It grows,
together with P. cembroides, on the lower slopes of the northeastern
Sierras of Mexico, near the boundary between the states of Tamaulipas
and Nuevo Leon. It is apparently confined to a small area near the
latitude of the city of Victoria, the capital of Tamaulipas, where its
nuts are often exposed for sale.

In many characters this species is unique. It can be recognized at
once by the connate leaves that form the fascicle or by the remarkable
stout curved peduncle of its cone. Such seeds as I have seen differ
from those of P. cembroides by a reddish area at one end, but this can
be seen with fresh seeds only.

Plate XIII.

Fig. 124, Cone, cone scale and seed. Fig. 125, Branchlet with
leaves. Fig. 126, Magnified section of a leaf-fascicle.

=V. GERARDIANAE=

Seeds with a very short ineffective articulate wing. Leaves in fascicles of 3, serrulate, the sheath deciduous. Bark exfoliating in large scales, leaving parti-colored areas.

These Asiatic Nut Pines are alike in leaf and cortex as well as in the
peculiar seed-wing. The last often remains in the cone after the nut
falls. The mechanical nature of this adhesion is apparent in P.
Gerardiana, where the wing adheres not to its own, but to the adjacent
scale. The two species are alike in their leaves but distinct in their
cones and seeds.

Cones smaller, the nut short-ovate 16. Bungeana.
Cones larger, the nut long-cylindrical 17. Gerardiana.

16. PINUS BUNGEANA

1847 P. Bungeana Zuccarini ex Endlicher, Syn. Conif. 166.

Spring-shoots glabrous, summer-shoots common on fruiting branches of young trees. Leaves from 6 to 10 cm. long, serrulate; stomata dorsal and ventral; resin-ducts external. Conelets subterminal or often pseudolateral, their scales gradually narrowed into a spine. Cones from 5 to 7 cm. long, short-pedunculate, short-ovate; apophyses dull pale nut-brown, elevated along a transverse keel, the dark brown umbo forming a spine with a broad base; seeds with a short loosely attached wing, sometimes remaining in the cone when the short-ovate nut falls.

A tree cultivated about the temples of China and recently found by
Wilson growing on the mountains of Hupeh. The earlier parti-colored
bark changes to chalky white on old trunks, by which the tree is
recognized from a great distance. The stem of the tree is often
multiple by the vertical growth of some of the lower branches. It is
very hardy and is cultivated in Europe and America, although these
cultivated trees are not yet of sufficient age to show the remarkable
white trunk.

Plate XIV.

Fig. 138, Cone and cone-scale with adhering wing. Fig. 139, Seed and
wing. Fig. 140, Leaf-fascicle and magnified leaf-section. Fig. 141,
Parti-colored bark. Fig. 142, Tree with white trunk.

17. PINUS GERARDIANA

1832 P. Gerardiana Wallich ex Lambert, Gen. Pin. ed. 8vo, ii. t. 79.

Spring-shoots glabrous. Leaves from 6 to 10 cm. long, serrulate; stomata dorsal and ventral; resin-ducts external. Scales of the conelet armed with a short spine. Cones from 9 to 15 cm. long, short-pedunculate, ovoid or oblong; apophyses fulvous brown, very thick, with a prominent reflexed or erect protuberance culminating in an umbo on which the spine is more or less persistent; nuts remarkably long, narrow, terete, the shell fragile, the short wing falling with the nut or adhering to the adjacent scale.

A tree of the northwestern Himalayas found on the borders of Cashmere
and Thibet and in Kafiristan and north Afghanistan, and so highly
prized for its nuts that it is rarely felled for its wood. It grows in
dry regions and rarely attains a height of 20 metres. Attempts to
cultivate this species, even in the milder parts of Great Britain,
have generally failed.

The apophysis of the cone varies much in prominence (figs. 134, 135),
but the peculiar seed is invariable and quite unlike that of any other
Pine. The general color of the trunk at a distance is silver-gray.

Plate XIV.

Fig. 133, Cone. Fig. 134, Cone-scale with adhering seed-wing. Fig.
135, Cone-scale of flatter form. Fig. 136, Seed and wing. Fig. 137,
Leaf-fascicle and magnified leaf-section.

=VI. BALFOURIANAE=

Seeds with long effective wings. Leaves entire, in fascicles of 5, the sheath deciduous.

The two species known as Foxtail Pines are alike in their short entire
falcate leaves, persisting for many years and forming long dense
foliage-masses. They differ in the armature of their cones and in
their seed-wings. The presence of both adnate and articulate wings in
these closely related species suggests that these two forms of wing
are not fundamentally distinct.

Cone-scales short-mucronate, the seed-wing adnate 18. Balfouriana.
Cone-scales long-aristate, the seed-wing articulate 19. aristata.

18. PINUS BALFOURIANA

1853 P. Balfouriana Balfour in Bot. Exp. Oregon, 1, f.

Spring-shoots somewhat puberulent. Leaves from 2 to 4 cm. long, persistent for many years; stomata ventral only; resin-ducts external. Scales of the conelet short-mucronate. Cones from 7 to 12 cm. long, tapering to a rounded apex, short-pedunculate; apophyses dark terracotta-brown, tumid, the umbo bearing a short recumbent prickle; seed with a long adnate wing.

An alpine species growing often at the timber-limit. It is found in
two distinct stations in California, on the northern Coast Range and
on the southern Sierras. It is not often cultivated, but young plants
may be seen in the Arnold Arboretum and in the Royal Gardens at Kew.

Plate XV.

Fig. 147, Cone, seed and enlarged cone-scale. Fig. 148,
Leaf-fascicle. Fig. 149, Magnified leaf-section. Fig. 150, A branch
with persistent leaves.

19. PINUS ARISTATA

1862 P. aristata Engelmann in Am. Jour. Sci. ser. 2, xxxiv. 331.
1871 P. Balfouriana Watson in King's Rep. v. 331 (not Balfour).

Spring-shoots glabrous or temporarily pubescent. Leaves from 2 to 4 cm. long, persistent for many years; stomata ventral only; resin-ducts external. Scales of the conelet prolonged into long slender bristles. Cones from 4 to 9 cm. long, subcylindrical or tapering to a rounded apex, short-pedunculate; apophyses terracotta or purple-brown, tumid, the long bristles of the umbo often partly or wholly broken away; seeds with a long articulate wing.

A bushy tree, similar in foliage to the preceding species, growing at
the timber-limit from Colorado through Utah, central and southern
Nevada and northern Arizona into southeastern California, but
separated from the nearest station of P. Balfouriana by an arid
treeless desert. Engelmann (in Brewer and Watson, Bot. Calif. ii. 125)
considered it to be a variety of P. Balfouriana.

Plate XV.

Fig. 143, Cone. Fig. 144, Seed and enlarged cone-scale. Fig. 145,
Leaf-fascicle and magnified leaf-section. Fig. 146, Conelet.

DIPLOXYLON

Bases of the bracts subtending leaf-fascicles decurrent. Leaves serrulate; fibro-vascular bundle double; stomata dorsal and ventral. Cones with a dorsal umbo, the phyllotaxis complex. Wood hard, with dark resinous bands, the annual rings clearly defined.

In this section there are a few species combining the essential
characters of Diploxylon with important characters of Haploxylon. A
subsection, Parapinaster, is established for these exceptional
species.

c. Parapinaster Species with the fascicle-sheath or seed-wing of
Haploxylon.
d. Pinaster Sheath persistent, seed-wing articulate, effective.

=Parapinaster=

Sheath of the leaf-fascicle deciduous VII. Leiophyllae.
Sheath of the leaf-fascicle persistent.
Seed-wing of the Strobi VIII. Longifoliae.
Seed-wing of the Gerardianae IX. Pineae.

=VII. LEIOPHYLLAE=

Sheath of the leaf-fascicles deciduous.
Leaves short, erect, the fructification triennial 20. leiophylla.
Leaves long, pendent, the fructification biennial 21. Lumholtzii.

20. PINUS LEIOPHYLLA

1831 P. leiophylla Schlechtendal and Chamisso in Linnaea, vi. 354.
1848 P. chihuahuana Engelmann in Wislizenus, Tour. Mex. 103.

Spring-shoots uninodal. Leaves in fascicles of 3, 4 or 5, the sheath deciduous, from 8 to 14 cm. long; resin-ducts medial with an occasional internal duct. Conelets single or verticillate, their scales mucronate; conelets of the second year only slightly enlarged. Cones maturing the third year, not exceeding 7 cm. in length, ovate or ovate-conic, subsymmetrical, more or less reflexed, persistent for several years on some trees, sometimes serotinous; apophyses lighter or darker brown, often with an olive or fuscous shade, thin or tumid, the umbo double, the mucro more persistent near the apex of the cone.

This species grows at subtropical or warm-temperate altitudes in
Mexico, from Oaxaca through the central and western states to southern
Arizona and New Mexico. As it approaches the northern part of its
range the leaves become thicker and more rigid and the number in the
fascicle is reduced to 3 or 4 (var. chihuahuana, Shaw, Pines Mex. 14).
Like P. rigida it sprouts freely along the branches and trunk, and
stumps of felled trees put out shoots in great numbers. The species is
easily recognized by the deciduous sheath and triennial cone.

Plate XVI.

Fig. 151, Branch with fruit of first, second and third years. Fig.
152, Leaf-fascicles. Fig. 153, Magnified leaf-section of the
species. Fig. 154, Magnified leaf-section of the variety.

21. PINUS LUMHOLTZII

1894 P. Lumholtzii Robinson & Fernald in Proc. Am. Acad. xxx. 122.

Spring-shoots uninodal, sometimes multinodal. Leaves in fascicles of 3, the sheath deciduous, from 20 to 30 cm. long, absolutely pendent; resin-ducts medial and internal. Conelets subterminal, or lateral and subterminal, mucronate. Cones not exceeding 7 cm. in length, symmetrical, pendent on slender peduncles, ovate-conic, early deciduous; apophyses sublustrous, nut-brown, tumid at the margins, flat on the surface, the umbo large, the mucro rarely persistent.

A remarkable Pine with long pendent bright green foliage, confined to
the western states of Mexico and ranging on the mountains from
southern Jalisco to the latitude of the city of Chihuahua. Each
season's growth of leaves hangs from the branchlet like a long beard,
from which the tree receives, in some localities, the name "Pino barba
caida." In the herbarium the long leaves, deciduous sheaths, and the
decurrent bases of the bracts, present a combination of characters not
found in other species.

Plate XVI.

Fig. 155, Cone. Fig. 156, Cone. Fig. 157, Leaf-fascicle. Fig. 158,
Magnified leaf-section. Fig. 159, Tree at Ferraria de Tula.

=VIII. LONGIFOLIAE=

Seed-wing adnate to the nut. Leaves long, in fascicles of 3, the sheath persistent.

Apophysis of the cone prolonged and reflexed 22. longifolia.
Apophysis of the cone low-pyramidal 23. canariensis.

22. PINUS LONGIFOLIA

1803 P. longifolia Roxburgh ex Lambert, Gen. Pin. i. 29, t. 21.
1897 P. Roxburghii Sargent, Silva N. Am. xi. 9.

Spring-shoots uninodal. Leaves in fascicles of 3, the sheath persistent, from 20 to 30 cm. long; resin-ducts external, the hypoderm often in large masses, some or all of the endoderm cells with thick outer walls. Cones from 10 to 17 cm. long, short-pedunculate, ovoid-conic; apophyses lustrous brown-ochre or fuscous brown, elevated into thick, often reflexed, beaks with obtuse mutic umbos; seeds with large nuts and adnate striated dark gray or fuscous brown wings.

Of the three Pines of the Himalayas this species is the most
important. It grows on the outer slopes and foot-hills from Bhotan to
Afghanistan. The wood is used for construction and for the manufacture
of charcoal, the thick soft bark is valuable for tanning, the resin is
abundant and of commercial importance, and the nuts are gathered for
food. The tree is not hardy in cool-temperate climates, but has been
successfully grown in northern Italy.

It differs from P. canariensis in the usually protuberant apophysis of
the cone, in the thick outer walls of the leaf-endoderm and in the
nearly smooth walls of the ray-tracheids of the wood. In the
dimensions of cone and leaf, in the dermal tissues and resin-ducts of
the leaf and in the peculiar coloring of the seed-wing, the two
species are alike.

Plate XVII.

Fig. 160, Cone. Fig. 161, Leaf-fascicle. Fig. 162, Magnified
leaf-section.

23. PINUS CANARIENSIS

1825 P. canariensis Smith in Buch, Canar. Ins. 159.

Spring-shoots uninodal, pruinose. Bud-scales with conspicuously long free fimbriate margins. Leaves in fascicles of 3, the sheath persistent, from 20 to 30 cm. long; the hypoderm often in large masses, the resin-ducts external, the endoderm with thin outer walls. Cones from 10 to 17 cm. long, short-pedunculate, ovoid-conic; apophyses lustrous or sublustrous nut-brown, more or less pyramidal, the umbo unarmed; seeds as in the last species.

A species confined to the Canary Islands, but cultivated in northern
Italy. The stately habit of this tree is seen in Schroeter's portrait
(Exc. Canar. Ins. t. 15).

Plate XVII.

Fig. 163, Cone and seed. Fig. 164, Magnified leaf-section. Fig. 165,
Habit of the tree.

=IX. PINEAE=

Seed-wing articulate, short, ineffective. Leaves binate, the sheath persistent. One species only.

24. PINUS PINEA

1753 P. pinea Linnaeus, Sp. Pl. 1000.
1778 P. sativa Lamarck, Fl. Franc. ii. 200.
1854 P. maderiensis Tenore in Ann. Sci. Nat. ser. 4, ii. 379.

Spring-shoots uninodal. Leaves from 12 to 20 cm. long; resin-ducts external. Conelet mutic, slightly larger in the second year. Cones triennial, from 10 to 14 cm. long, ovoid or subglobose; apophyses lustrous nut-brown, convex, of large size, the umbo double; seeds large with a short, loosely articulated, deciduous wing.

A species of the Mediterranean Basin, from Portugal to Syria. Its
northern limit is in southern France and northern Italy, but it is
cultivated in the southern parts of the British Isles and is a
familiar ornament of park and garden in southern Europe, and is valued
for its peculiar beauty and for its large savory nuts. In wood anatomy
as well as in the seed it agrees with the Gerardianae of the Soft
Pines.

Plate XVIII.

Fig. 166, Fruit of three seasons. Fig. 167, Cone-scales and seed.
Fig. 168, Magnified leaf-section. Fig. 169, Habit of the tree.

=Pinaster=

Bases of the bracts subtending leaf-fascicles decurrent. Seeds with an effective articulate wing. Umbo of the cone-scales dorsal. Leaves serrulate, stomatiferous on all faces, the sheath persistent. Walls of the tracheids of the medullary rays dentate.

Forty-two of the sixty-six species of Pinus are included in this
subsection. As a group they are clearly circumscribed by several
correlated characters and are more closely interrelated than the
twenty-four species previously described. The distinctions of umbo and
seed have disappeared. The umbo here is invariably dorsal, the
seed-wing invariably articulate.

New forms, however, are gradually evolved--the seed with a thick
wing-blade, the indurated oblique cone, the serotinous cone with its
intermittent seed-release, and the multinodal spring-shoot. There are,
moreover, new forms of leaf-hypoderm and a new position of the
resin-duct.

Of these new characters, the thick wing-blade attains such proportions
in the three species of the Macrocarpae that they can be grouped
apart. But the characters that finally culminate in a lateral oblique
serotinous cone are so gradually and irregularly developed that they
offer no divisional distinctions. With the aid of wood and leaf
characters, however, groups can be established which preserve the
evolutionary sequence and, at the same time, the obvious affinity of
the species.

Wing-blade thin or slightly thickened at the base.
Cones dehiscent at maturity.
Pits of the ray-cells large X. Lariciones
Pits of the ray-cells small XI. Australes
Cones serotinous, pits of the ray-cells small XII. Insignes
Wing-blade very thick XIII. Macrocarpae

The species of this subsection are very difficult, if not impossible,
to classify by the usual method, which groups all species under a few
characters assumed to be invariable and of fundamental importance.
Such a method can be successfully applied to the Soft Pines and to
some of the Hard Pines, but cannot be applied to all the Hard Pines
without forcing some of them into unnatural associations.

To take an example, the group Pseudostrobus, characterized by
pentamerous leaf-fascicles, appears in many systems. In this group are
placed P. Torreyana and P. leiophylla. Another group, with trimerous
fascicles, contains P. Sabiniana and P. taeda. Now there are no two
species more obviously related by important peculiarities than P.
Torreyana and P. Sabiniana; nevertheless they are, by this method,
kept apart and associated with species which they resemble in no
important particular.

An attempt is made here to avoid such incongruities. Groups X, XI and
XII represent different stages of evolution. In the Lariciones the
cone is symmetrical, and dehiscent and deciduous at maturity, while
the spring-shoot is uninodal. In the Australes there is a similar
cone, but the spring-shoot gradually becomes multinodal. In the
Insignes the cone is oblique, persistent and serotinous, and the
spring-shoot is multinodal.

These definitions state the degree of evolution attained by each
group, but not all the species of a group conform exactly with its
definition. In each group are species with a characteristic of another
group. Among the Lariciones are a few species with both symmetrical
and oblique cones, and two with persistent cones. Similar exceptions
occur among the Australes. Among the Insignes are a few species with
symmetrical cones, and two with cones that are rarely, if ever,
serotinous.