Chapter IX (1)

CLASSIFICATION OF GRASSES BY THE “SEEDS” (GRAINS).

+I. “Seed” rounded (Millet-seed[12] type). Caryopsis ovoid or
sub-globose, devoid of distinct groove, and distending the awnless
paleæ, or falling out free.+

+A. Glumes cuspidate, “fruit” yellowish.+

_Phleum pratense._

The student should familiarise himself with the “seed” of _Phleum pratense_, as a type, and an important grass easily obtained pure, but sometimes with minute round seeds of weeds intermixed.

_Phleum pratense_, L. (Fig. 45).

Palea 2·3 mm. long, five-ribbed, with a short point, delicate but hard, smooth, with a silvery lustre. Inner pale two-nerved. Closely investing the yellow-brown caryopsis, which easily falls out and is ovoid-acute, about 2 mm. long by 1 broad, and finely punctate.

The much rarer _P. arenarium_ and the very rare _P. Bœhmeri_ and
_P. asperum_ also come here.

_Phleum_ is not easily confounded with any other of our grasses,
and _Briza_ and _Glyceria_ are almost the only other common grasses
of about the same size of which the caryopsis often falls free from
the palea (“naked fruits”). _Glyceria_ is longer and corn-shaped,
and _Briza_ usually larger. _Anthoxanthum_ and _Phalaris_ are easily
distinguished. _Agrostis_ is smaller and “corn-shaped.” Certain
species of _Panicum_ present resemblances, but the enveloping paleæ,
&c. are very different. _Melica_ also occurs as “naked fruits,” but
is rarely seen, and its colour and brilliant lustre distinguish it.

+B. Glumes not cuspidate. “Fruit” not yellow.+

(_a_) “Fruit” white, owing to the closely investing palea.

_Milium effusum._

A common grass, but not often met with in “seed” grasses. It is
eagerly eaten by birds.

_Milium effusum_, L. (Fig. 52).

Palea about 3 mm. long, with few nerves, closely investing the caryopsis: the seed is ellipsoid-acute, slightly compressed, and 2·2-2·7 mm. long. The inner pale becomes hard and shines like porcelain.

(_b_) “Fruit” dark-brown shining; slightly flattened and grooved.

+Melica.+

_Melica_ is rarely met with as “seed.” When it is, it has to be
distinguished from the other “Millet-seed” types which readily fall
as naked fruits--see _Phleum_, _Milium_, &c. _Agrostis_, _Glyceria_
and other corn-shaped “seeds” are easily distinguished.

_Melica nutans_, L. (Fig. 53).

“Seed” coracle-shaped. Palea broad, parchment-like, elliptic convex, 5-6 mm. long, 5-7 nerved and keeled, awnless, loose, purplish. Caryopsis ellipsoid-acute, 2-3 mm. long, and easily separating, wrinkled, dark shining brown as if lacquered.

_M. uniflora_, Retz. is commoner and very similar, but neither is
often met with in “seed” grass, except as impurities among Fescues.

The rare _Panicum Crus-galli_ and allies, and the rice-like _Leersia
oryzoides_ as well as _Cynodon Dactylon_, come here.

Panicums may occur in grass “seed” from America: Burchard describes
them in detail.

+II. “Seed” long (Corn and Barley type). Caryopsis oblong or
flattened, usually trapped between the boat-shaped paleæ: if
otherwise, with an awn.+

+A. “Seed” awnless. There may be a short sharp point to the palea
(mucronate), but no prominent hair-or bristle-awn exceeding half
the length of the palea.+

(_a_) A “web” or tuft of hairs at the base or on the rachilla.

(1) _Hairs of basal tuft silky and erect._

* Pencil of hairs as long as palea or longer.

_Calamagrostis lanceolata_, Roth.

Palea 3 mm. long, thin, two-toothed and with a short bristle at the apex.

Other species of _Calamagrostis_ are awned. None occurs as an
ordinary impurity in “seed.”

_Arundo Phragmites_, L.

Palea narrow and long, 10-11 mm., delicate, entire, tapering to an acuminate point, violet, three-nerved, smooth. Caryopsis about 2 mm. A pencil of long silky hairs on the rachilla.

The long acuminate point is almost an awn.

_Calamagrostis_ also has long basal hairs: both are useless grasses
agriculturally. For _Glyceria_ see note, p. 146. _Avena_, _Aira_ and
_Psamma_ are easily distinguished.

** Pencil of hairs short.

† _Palea mucronate, 11-12 mm. long: caryopsis 4·5 mm._

_Psamma arenaria._

_Digraphis_ differs in the stout caryopsis, smaller size, double
hair-tuft. _Arundo_ has a long pointed palea and long silky basal
hairs and is larger.

_Psamma arenaria_, Beauv.

Palea 11·5 mm. ovate-lanceolate, papery, 4-5 nerved, as rolled round the fruit about 1·3 mm. diameter, yellow, and with a small tuft of stiff fine hairs at the base. Mere trace of awn, sub-terminal. Fruit 4-5 mm. long, obovate, pale-brown.

A shore-grass, not often seen as “seed”: more valuable as a
sand-binder than as fodder, though the young shoots are grazed.

†† _Palea acuminate, and only about 4 mm. long: caryopsis
1·4 mm._

_Digraphis arundinacea._

A Fen-grass, but coarse and not in use except the young growth, and
for thatching.

_Digraphis arundinacea_, Trin.

Paleæ ovate-lanceolate, nerveless and awnless, but silky with double basal hair-tuft, and polished at the base; smooth, hard and shining, and closely investing the caryopsis which has no groove. Dark grey in colour. The glumes are without awns or wings, and are left behind.

The allied _Phalaris canariensis_ has wing-like keels to the glumes.

_Triodia_ also comes into this group, with short basal hairs; but its
broad ciliate palea, 6 mm. long, has a short mucronate point between
two teeth (Fig. 40).

(2) _Hairs at the base forming a fluffy “web.” Paleæ thin,
2-3 mm. long._

_Poa pratensis._
_P. trivialis._
_P. compressa._
_P. nemoralis._

The “seeds” of _Poa_ proper are nearly all small--not more than 3-4
mm., more or less lanceolate, with tough, keeled glumes, and when
“webbed” tend to adhere together as if stuck with cobweb. The keeled
glumes give them an angular appearance--triangular in section--and
make them tend to lie on the side. Rachilla evident. Nerves of paleæ
distinct.

_Poa pratensis_, L. (Fig. 55).

“Seed” 2-3 mm. long, brownish: caryopsis about 1-1·5 mm. Outer palea acute, indistinctly 3-5 nerved, edges and keel, silky; margins overlapping the hyaline inner palea.

The “web” looks like hyphæ of a mould.

Caryopsis ellipsoid-acute, with traces of the stigma. It falls easily. No distinct groove, section somewhat triangular. Rachilla truncate.

_Poa compressa_, L.

Palea obtuse, nearly glabrous and nerveless, or faintly 3-5 nerved and with a faint web. It is close to _P. pratensis_.

_Poa trivialis_, L. (Fig. 56).

“Seed” 2-2·5 mm., and with a bluish or bronzed cast. Caryopsis 1-1·5 mm.

Palea acute, distinctly five-ribbed, glabrous, the margin scarcely overlapping. Caryopsis grooved, blunt and more tightly held in the palea.

_P. trivialis_ differs from _P. pratensis_ chiefly in the distinct
ribs and smoother palea, grooved caryopsis, and bluer hue.

_P. nemoralis_, L., hardly differs from _P. trivialis_, but the paleæ are sub-acute, nerves obsolete, and scarcely hyaline at the margins. The “seed” is shorter and more acute, and the colour less pronounced, and with hardly a trace of hairs (Fig. 54).

When the basal hairs are absent this should go with _P. annua_, &c. (see p. 146).

It is practically impossible to distinguish these species by the
“seed.” Care is necessary to distinguish _Kœleria_, which is
somewhat larger in size, keeled, compressed and nerved similarly,
but is more pointed and curved and paler yellowish white in colour.
Hard and devoid of web or hairs. _Aira_ is distinguished by the awn:
_Agrostis_ by the very different paleæ and caryopsis.

The other Poas are devoid of web, though they may have hairs below,
and require very careful examination. The whole group is excessively
difficult to deal with in “seed,” and a special study of it is
needed, since several species are important, and it forms a type.

_b_ No web or pencil of hairs below the “seed.”

(1) _Apex of palea rounded, blunt, notched, or at most bluntly
pointed, but with no trace of awn-or bristle-tip._

* Palea inflated, round-backed and somewhat winged,
membranous.

_Briza media._
_B. minor._

_Briza media_, L.

Paleæ blunt, 2·5-3 mm., without lateral projections, markedly convex--almost conduplicate; nerves several. Caryopsis ovoid, 1·5-2·5 mm., dark brown.

Sometimes called a good grass, but meagre and only found in poor
meadows in this country.

It should perhaps go with the “Millet-seed” type and should be
compared with _Phleum_, _Melica_, _Panicum_, &c. “Seed” seldom met
with.

_B. minor_ is smaller.

** Paleæ not inflated or winged.

† _Paleæ broad, flat and truncate, prominently three-ribbed.
Caryopsis 2 mm. long._

_Catabrosa aquatica_, Beauv.

Cattle like it, but it only grows in ditches &c. in water-meadows:
distinction from _Glyceria aquatica_ easy if the paleæ are examined.

†† _Paleæ acute or sub-acute, boat-shaped._

⊙ _Paleæ and “seed” at least 6-8 mm. long._

≡ _Rachilla flattened or angular, and tapering below._

_Lolium perenne._

Occasionally awned, and then less easily distinguished from _L.
temulentum_. One of our most valuable grasses. It forms a distinct
type of boat-shaped “seeds.”

_Lolium perenne_, L. (Fig. 57).

Palea distinctly five-ribbed, glabrous, oblong-lanceolate, obtuse or sub-acute, awnless, about 7 mm. long. Margins membranous. Inner palea nearly as long, delicate, ciliate.

Rachilla short, flattened and angular, tapering below (see _Festuca elatior_).

Caryopsis about 3·5 mm. long, obovate, yellowish brown.

Although _Bromus mollis_, _Holcus lanatus_, &c. occur as impurities,
they are easily distinguished: the real difficulties are with
_Festuca elatior_ and _F. pratensis_.

≡≡ _Rachilla cylindrical._

_Festuca elatior._

This is an important grass, and should be thoroughly mastered as a
type of the boat-shaped “seed.”

This, with _Lolium_, _Agropyrum_, other Fescues, and even some Bromes
and Poas, will give trouble until the student thoroughly masters
the importance of the minute characters of size, nervature, of the
rachilla, awn, palea, &c.

_Festuca elatior_, L. (var. _pratensis_) (Fig. 58).

Palea ovate-lanceolate, five-nerved, slightly scabrid, with a slight membranous margin and cilia, rounded back, and no awn. 6-7·5 mm. long.

Caryopsis oblong-obovate, somewhat flattened, hardly grooved and adhering to the paleæ, about 3-3·5 mm. long.

Rachilla cylindrical, smooth.

The other varieties of _F. elatior_ cannot be distinguished by the
“seed” alone: in my samples _F. elatior_ proper is longer than
_F. pratensis_, and both have occasionally a trace of awn. Var.
_arundinacea_ has a more acuminate, stiff point. _Festuca pratensis_
has its palea as a rule somewhat more acute than _Lolium perenne_,
and the flatter tapering rachilla of the latter is more closely
appressed to the palea. The caryopsis of _Festuca_ also tends to
adhere to the paleæ.

⊙⊙ _Paleæ and “seed” at most 3-3·5 mm. long._

≡ _Palea devoid of hairs or keel, notched or blunt,
and with no trace of awn._

Δ _Palea hyaline, nerves indistinct. Tips notched
or blunt._

_Agrostis alba._

There is occasionally a very short basal hair (awn).

_Agrostis_ and _Aira_ will present difficulties to the beginner, not
only on account of their small sizes, but also from the variability
as regards awns, basal hair-tuft, &c. None are of value, and most of
them are weeds.

_Agrostis alba_, L. (var. _stolonifera_).

Palea enclosing the fruit 1·8-2 mm. long, white, delicate, membranous, with a blunt notched apex and three (or five) nerves: occasionally there is a fine kneed basal awn, not projecting.

The glumes may remain attached: the outer has a serrulate keel, and often a violet hue. No awn. About 2-3 mm.

Caryopsis about 1·1 mm. long, oblong, yellow, corn-shaped, furrowed, shining through.

_A. vulgaris_, L., is a variety with slightly smaller fruits, no awn, and usually three nerves to the palea, but they cannot be distinguished with certainty by the “seed.” Rachilla obsolete.

The colour of the glumes may vary considerably and is sometimes
yellow.

The absence of awn, rachilla, and basal hairs distinguishes
_Agrostis_ from _Aira_.

ΔΔ _Palea membranous, ribbed, tips scarious._

_Glyceria aquatica._
_G. fluitans._

_Glyceria aquatica_, Sm.

Palea strongly 5-7 ribbed, obtuse and scarious, about 4 mm. long. Green with a purple cast. Caryopsis dark-brown, about 2 mm. long.

Inner palea punctate. Rachilla slender and cylindrical.

_Glyceria fluitans_, Br., is very similar, but longer (6 mm.) and more slender; the palea scabrid with truncate or ragged tips, and the inner palea not punctate. Yellow. (Fig. 46.)

_Glyceria aquatica_ and _G. fluitans_ are sweet grasses of value in
water-meadows only. The “seed” is not often met with.

Not only with the Poas, but also with _Catabrosa_ are there
difficulties in determination. _Molinia_ and _Kœleria_ also
present difficulties with _Glyceria_: the former has fewer and
feebler nerves. _Digraphis_ and _Arundo_ are easily distinguished by
the basal hairs.

≡≡ _Palea acute and somewhat compressed and keeled,
and with hairs on the ribs. Tips nerved._

_Poa annua._
_P. maritima._
_P. distans._
_P. rigida._
_P. loliacea._
_P. bulbosa._
_P. alpina._

Their “seeds” are all small, about 2-3·5 mm. only, and angular,
brown, and present many difficulties (see note, p. 141).

_Poa annua_, L. (Fig. 43).

Palea 3·5 and caryopsis 2 mm. long, so that the “seed” is much larger than _P. trivialis_, and there is no web. Minutely silky-hairy on the keel, and the ribs are strong for a _Poa_.

_Poa alpina_, L., has the palea five-ribbed with stiffish hairs below, but no web. Bronzy green-violet. “Seed” 3-3·5 mm. long. Caryopsis 1·5-2 mm., and slightly grooved. It is rare in England, and is interesting as it becomes viviparous in Alpine situations.

(2) _Apex of palea distinctly pointed, acuminate or mucronate,
but not giving rise to a true, long, bristle-like awn._

* Palea acuminate--i.e. taper pointed.

† Not compressed or obviously keeled.

_Festuca ovina._
_F. sylvatica._
_Cynosurus cristatus._

It is doubtful whether these should not be regarded as awned: if so
they come near _Nardus_--see p. 130.

_Festuca ovina_, L. (Fig. 59).

Palea rounded on the back, narrow, terete-lanceolate and five-nerved, tip scaberulous and drawn out to a stiff scabrid point half as long as the palea, or less. About 3-4 mm. long without the tip-point, 4-5·5 mm. with it. Rachilla obliquely truncate and concave at its apex.

Caryopsis oblong, somewhat flattened, dark-brown.

The numerous varieties of _F. ovina_ cannot be distinguished by the
“seed”: the allied varieties _F. rubra_, _F. duriuscula_, and _F.
heterophylla_, &c. are sometimes more distinctly awned (see p. 172).
But difficulties will be found with the whole group, which needs
revision. This group comprises the grasses so valued on downs and dry
hill-pastures for sheep-feeding.

_Festuca sylvatica_, Vill., not a common plant, is also with
difficulty separable (Fig. 51).

_Cynosurus cristatus_, L. (Fig. 60).

Palea canary yellow to light-brown, lanceolate with rounded back and the mid-rib prominent as a slight keel and margins infolded, about 4 mm. long (varies from 3-4·5 × 0·5 to 1 mm. broad), scabrid above, dotted below and acute to acuminate with a scabrid awn-point, often curved. Caryopsis 2-2·3 mm., somewhat flattened. Rachilla short and smooth, dilated above.

A valuable and easily recognised grass. _Molinia_, _Holcus_ and
similar impurities are easily detected: some Fescues are much more
like it; e.g. _F. tenuifolia_ (see p. 46) in which the apex tapers
suddenly to a point. _Dactylis_ should also be compared.

†† Paleæ compressed or distinctly keeled.

_Molinia cærulea._
_Kœleria cristata._

Unimportant, except as impurities among other grass “seeds.”
_Molinia_ is said to occur as such in samples of _Cynosurus_,
_Dactylis, Poa trivialis_, Fescues, &c., but it should give little
difficulty except in comparison with _Glyceria_ (see p. 146).

_Molinia cærulea_ (Mœnch.) (Fig. 61).

“Seed” 3-4 mm. or more, leather coloured or with a bluish tinge. Paleæ divaricating, the lower keeled and compressed, and tapering to a sharp point. Rachilla long, oblique and prominent. Smooth tapering, palea 5·5, fruit 2 mm. long.

_Kœleria cristata_, Pers. (Fig. 62).

Palea 6 mm., keeled, entire, no awn but stiffly tapering, ribbed, no hairs. Rachilla large. Fruit 4·5 mm.

** Palea not taper pointed, but mucronate, or two-toothed,
with a sub-terminal point or spine.

_Elymus arenarius._
_Agropyrum repens._
_Dactylis glomerata._
_Sesleria cærulea._

_Elymus arenarius_, L. (Fig. 63).

Fruiting palea lanceolate, 13-15 × 3 mm., tough and stiffly hairy or velvety: 5-7 ribs. Rachilla stout, hairy. Fruit hairy above, 5-11 mm. × 2·5 × 1·2, somewhat grooved. No keel. Apex of inner palea bifid, outer mucronate. Fruit shelled.

Easily distinguished from _Digraphis arundinacea_, which has a basal
hair-tuft and very different caryopsis; less easily from _Agropyrum_
and _Lolium_, except in the velvety surface.

_Agropyrum repens_ may have a mucronate awn-point or not. The small palea 10-12, the caryopsis 5-6 mm. (see p. 169 for description).

This troublesome weed (Couch-grass) presents similar difficulties
with _Lolium perenne_ that _Agropyrum caninum_ does with _Lolium
temulentum_--see p. 168. It is moreover extremely variable.

_Dactylis glomerata_, L. (Fig. 64).

Stiff awn-point just below the two teeth of apex of pale. Rachilla dilated above. Paleæ 5-6 mm. long exclusive of point, compressed and inflated, ribbed and ciliate-bristly on keel, the tip incurved. Caryopsis yellow-brown, ellipsoid, 2 mm.

An important grass, said to be adulterated with _Lolium_, Fescues,
_Holcus_, _Molinia_, _Bromus_, &c., most of which should be readily
detected. The curved tip is an important distinctive character.
_Cynosurus_ and _Festuca arundinacea_, _F. ovina_ and _F. rubra_
present resemblances. The seed is larger than that of _Poa_.

_F. ovina_ and _F. rubra_ are smaller, rounded dorsally, and have no
keel or cilia: the nerves are less prominent and the rachilla smaller.

_Sesleria cærulea_, Ard.

Palea distinctly toothed at the apex, making it almost three-lobed and very characteristic; with awn-point; five ribs, serrulate. Fruit grey-yellow, obovate.

It is a mountain-and moor-grass of little value.

+B. “Seed” awned--i.e. the investing palea bears, or tapers into,
a distinct bristle or hair at least as long as itself or nearly
so.+

(_a_) Awn not terminal.

(1) _Awn stout, either obviously twisted and bent or “kneed.”_

(i) “Seed” consisting of the glumes as well as paleæ investing
the caryopsis[13].

⊙ _Awn bent but not twisted; glumes free below, ribbed, and
with stiff short hairs on the keel._

≡ _Awn sub-terminal, shorter than the palea, hooked._

_Holcus lanatus._

“Yorkshire Fog,” of little use or importance, except that it is
frequently found as an impurity of other hairy grasses--e.g.
_Alopecurus_.

It cannot easily be confounded with any other grass: _Anthoxanthum_
and _Alopecurus_, _Arrhenatherum_, &c. present superficial
resemblances only.

These glumed hairy “seeds” are uncommon and form an easily recognised
type.

_Holcus lanatus_, L. (Fig. 65).

The “seed” consists of the complete spikelet, separated below the compressed and acute, keeled glumes; these have hairs on the keel, and completely enclose the two flowers and their paleæ. Palea ribless, white to grey, shining, obtuse, that of the upper (male) flower with a sub-terminal short hook-like awn. Total length about 4-5 mm. Caryopsis oblong-ovate, grooved. In its palea about 2-3 mm. long and with a few hairs at the base.

≡≡ _Awn dorsal, kneed, longer than the palea._

_Holcus mollis_, L. (Fig. 66).

Palea 2·5 mm., fruit 3·1 mm. long; glumes with stiff hairs or serrulæ on keel.

The seeds of _Holcus_ often fall from the glumes, but may bring them away.

_Holcus_ is of little use. The two-flowered spikelets and peculiar
awns sufficiently distinguish it among the smaller forms. It is said
to occur as an adulterant in “seed” of _Alopecurus_.

⊙⊙ _Awn bent and twisted, basal or nearly so; glumes very
hairy._

Δ _Glumes golden brown: one awn straight, one “kneed.”_

_Anthoxanthum odoratum._

The grass which gives the scent to new-mown hay. The “seed” is often
impure, containing a continental species _A. Puelii_ and other hairy
forms.

_Anthoxanthum odoratum_, L. (Fig. 67).

The one-flowered spikelet has four hairy glumes, the outer pair of which are unequal and awnless: the “seed” consists of the inner pair of golden-brown hairy and dorsally awned glumes, covering the thin, membranous, shining, smooth, blunt paleæ and the caryopsis, to which the inner palea adheres. Total length, without awns, about 3-4 mm. Palea 1·6 mm. Caryopsis 1·5 mm., brown, shiny, and easily separating. One awn is short, stiff and straight and inserted above the middle of its glume; the other longer and sharply bent, inserted about the middle.

_Hierochloe_, a rare northern grass, also comes here.

ΔΔ _Glumes connate below, hairy on the keels._

_Alopecurus pratensis._
_A. geniculatus._
_A. agrestis._

_Alopecurus_ is very characteristic, and should be carefully examined
as a type. _A. pratensis_ is a valuable grass and said to be often
adulterated with the undesirable _A. agrestis_, _Holcus_, &c.
_Arrhenatherum_ and _Avena_ are easily distinguished by the basal
hairs, rachilla, &c.

_Alopecurus pratensis_, L. (Fig. 68).

Inner palea absent. Outer palea 5 mm., caryopsis 3 mm. long, often with remains of the stigma.

The greyish-brown spikelet of _Alopecurus_ easily falls as a whole, included in the glumes; the palea is loose and delicate.

Glumes connate below, silky-hairy on keel and ribs all the way up. The palea has a bent dorsal awn, about 5 mm. long.

_Alopecurus geniculatus_, L.

Palea 2 mm., fruit 1·3 mm. long.

The glumes hairy on ribs and keel as in _A. pratensis_: glumes more obtuse.

_Alopecurus agrestis_, L.

Palea 6 mm., fruit 3 mm. long.

Glumes only ciliate, on ribs and keel, except at the base where the hairs are longer.

Keel slightly winged.

Best distinguished from _A. pratensis_ by the glumes, which are
smoother, broader above the middle, harder and with a few basal hairs.

The species _A. fulvus_, _A. bulbosus_, and _A. alpinus_ are rare.

(ii) “Seed” consisting of the paleæ investing the caryopsis,
freed from the glumes.

* _Palea at least 14 or 15 mm. long: caryopsis 5-7 mm. [Oat
type.]_

_Avena fatua._ _A. pratensis._

_Avena fatua_, L.

Palea parchment-like, lanceolate-terete, acuminate and bifid at the apex, rounded on the back and with yellow hairs on the lower part. 15 × 3 mm. Awn brown, twisted and bent, arising from the middle, about 30 mm. long. Caryopsis 7 mm. long, hairy at the top and distinctly grooved. Rachilla with fine bristles.

_Avena pratensis_, L.

Palea very similar to _A. fatua_, apex 2--4-toothed or bifid, rachilla with stiffer hairs. Caryopsis about 5 mm. long.

_Avena pubescens_, Huds. is a variety of _A. pratensis_ found on dry calcareous soils. The caryopsis is very narrow, and the rachilla long and feathered with hairs. “Seed” shorter than _A. pratensis_, 10-13 mm., and darker in colour.

_A. fatua_ is an excellent type of the grasses with dorsal twisted
and bent awns, and easily examined on account of its size. The
student will find difficulties with other species of _Avena_ and
_Arrhenatherum_.

Harz says the stiff hairs of _Avena_ bring about the formation of
intestinal concretions (phytobezoars) and are therefore dangerous to
domestic animals.

** _Palea not more than 7-10 mm. long._

† _Caryopsis 4-5 mm. long._

_Arrhenatherum avenaceum_, Beauv. (Fig. 47).

Paleæ papery, ribbed. Awn 13-15 mm., twisted below; paleæ, with a tuft of hairs below and a ciliate keel, investing the fruit: the whole being cylindrical, 8-10 mm. × 1·5.

Caryopsis 4-5 mm. × 1·2, fusiform, pubescent. Rachilla hairy.

The distinctive difference between _Avena_ and _Arrhenatherum_ is in
the spikelets as a whole. The latter has the lower flower of each
spikelet male only. Samples contain the “double seeds,” and the awn
of the upper fertile portion is short (see Fig. 69).

†† _Caryopsis not more than 3 mm. long. A tuft of hairs on
rachilla and base._

_Avena flavescens._

_Aira flexuosa_, distinguished by its nearly basal awn, harder
texture and darker colour of paleæ, and _Dactylis_--awnless and with
curved long drawn-out apex--are found as impurities in foreign “seed.”

_Avena flavescens_, L. (Fig. 69).

Yellow. Palea about 5 mm. long, five-ribbed, bifid at the apex into two long slender teeth, closely investing the brownish caryopsis, and with a sub-dorsal awn 10 mm. long with little or no twist, and hairy at the base. Rachilla flattened and with white hairs. Caryopsis not much grooved, fusiform, 2-3 mm. long, glumes unequal, somewhat keeled and rough.

(2) _Awn dorsal or basal, fine and hair-like, and little or not
at all twisted or kneed. “Seed” small._

* A pencil of silky hairs on base or rachilla. Palea bifid at
the tip.

† _Basal hairs longer than palea, and obscuring the awn._

_Calamagrostis Epigeios._

Of little importance. _Digraphis_ has no awn.

_Calamagrostis Epigeios_, Roth.

Palea about 3 mm. long with toothed apex and very thin caryopsis 1 mm. A conspicuous tuft of fine silky hairs, longer than the palea at the base and on the rachilla.

Awn slender, dorsal, about as long as the palea.

_C. stricta_, Nutt. and _C. strigosa_, Hartm. are rare.

†† _Basal hairs shorter than palea._

⊙ _Awn brown, bearded in the middle, thickened and white
above._

_Aira canescens._

The student will find considerable difficulties in the various
species of _Aira_ and _Agrostis_, owing to their small size and
variability as regards awn and basal hair-tufts. All these are weeds,
but some occur as adulterants.

_Aira canescens_, L.

“Seed” (apart from the awn, it is very like _Agrostis_) 1·5-2 mm., with a very thin, smooth, keeled, two-nerved palea, bifid at its apex, through which the yellow caryopsis shines.

Awn slender, basal, dark-brown, with oblique colourless hairs above the middle and with a slight swelling above.

The palea has a few hairs on its mid-rib below.

Caryopsis about 1 mm. long.

This grass is somewhat rare in England. The jointed basal awn,
with a minute hair-tuft above the middle, is unique, and readily
distinguishes it when mixed with _Agrostis_.

⊙⊙ _Awn not bearded or thickened._

≡ _Palea bifid at apex._

_Aira caryophyllea._
_A. præcox._

_Aira caryophyllea_, L.

“Seed” 1·4-1·6 mm., comma-shaped and dark-brown.

Palea acute, nerveless, inrolled at edges and with a dorsal, kneed, very fine, dark twisted awn twice as long as the palea: the latter with two-toothed apex and a basal hair-tuft.

A common impurity in commercial seed.

_Aira præcox_, L. is very similar, and cannot be distinguished with
certainty by the “seed,” but has a shorter awn and no basal hairs.
Apex of palea two-toothed.

≡≡ _Palea jagged or toothed, but not bifid._

_Aira flexuosa._
_A. cæspitosa._

_Aira flexuosa_, L. (Fig. 70).

Palea 5 mm. long, four-toothed at the apex, and caryopsis 2·6 mm. The fine basal awn waved or kneed, about twice as long as the palea. Fruit with a groove.

Rachilla hairy. Whole “seed” browner than _Avena flavescens_ (see p. 158).

An almost worthless grass, on sandy soils, but important as an
impurity in _Avena flavescens_ (see note, p. 158).

_Aira cæspitosa_, L. (Fig. 44).

The palea, about 2·5 mm. long, toothed above, has a fine straight hair-like basal awn not longer than itself. Caryopsis 1·3 mm., grooved. Rachilla distinctly hairy.

Easily distinguished when mixed with _Poa nemoralis_, &c.--e.g. by
the awn, hairs on rachilla, &c. It requires scrutiny in regard to
_Agrostis_, which also has no awn or basal hairs.

** No basal tuft, or merely a few short microscopic hairs
below. Paleæ not bifid above.

_Agrostis canina._
_A. Spica-venti._
_A. setacea._

_Agrostis canina_, L., is somewhat larger than _A. alba_. Palea (only one present, sometimes minute) punctate, 2 mm., with a fine dorsal awn a little longer than the palea. Caryopsis 1·2 mm. Rachilla obsolete.

The awn is usually absent from _A. alba_ and its varieties; and when
present is so small as to be almost negligible.

_A. canina_ is easily distinguished from _Poa_ by the rachilla in the
latter, and absence of awn. _Aira_ has basal hairs, &c.

_Agrostis setacea_, Curt., has the awn basal and just projecting beyond the pointed glumes, and the palea very minute, with a few silky hairs below.

_Agrostis Spica-venti_, L. (Fig. 49).

Palea 2·4 mm. long, with infolded edges and punctate; a minute rachilla at its base, and a slender awn, 8-9 mm. or more long, inserted below the bifid tip. Caryopsis 1·5 mm. A few silky hairs at the base of the palea.

(_b_) Awn terminal or slightly sub-terminal, and straight, or at
least not twisted or “kneed.”

(1) _Paleæ so closely adherent to the fruit that the terminal awn
appears to come from the latter [Barley type]. The three
florets generally coherent._

✲ _Awn at least twice the length of the grain._

_Hordeum sylvaticum._
_H. murinum._

_Hordeum sylvaticum_, Huds.

Palea scabrid, ribbed above, awn at least twice as long as the very narrow grain.

_Hordeum murinum_, L.

Lower palea 9-10 mm. long, five-ribbed, lanceolate and wrapped round and adhering to the fruit (grain), upper palea also ribbed. The grain about 7-8 mm. × 2 × 1·2, hardly grooved. Awn about 30 mm. long, serrulate. Rachilla slightly serrulate.

** _Awn not twice the length of the grain._

_Hordeum pratense._
_H. maritimum._

_Hordeum pratense_, Huds.

Spikelet with a reddish tinge; awn almost smooth, less than 20 mm. long: not twice the length of the smooth and obscurely nerved grain.

_Hordeum maritimum_, With., similar to _H. pratense_, but softer and the awn somewhat longer.

The principal features of the _Hordeum_-grain are the closely
adherent paleæ and angular fruit, the stiff awn appearing to come off
from it as in _Barley_. The rachilla remains.

They are all weeds of no use in agriculture, though _H. pratense_ is
not uncommon in good pastures.

(2) _Palea investing the caryopsis, often closely, but not fused
with it, and its tip and awn quite free._

* Awn not strictly terminal but sub-terminal, or arising from
between two teeth or in a sinus at the apex of the palea.

† Caryopsis thin, flattened and usually 6-10 mm. long, and
the paleæ hairy.

≡ _Palea inrolled, terete-lanceolate-acuminate, or
linear-lanceolate (barge-shaped). Apical teeth minute
and pointed._

Δ _Palea scaberulous or hairy, awn from half to about
its own length._

_Bromus erectus._
_B. asper._

_Bromus erectus_, Huds.

Palea with 5-7 scaberulous ribs, but not hairy, flat above, incurved below, so that the inner palea is clearly visible. About 10-14 mm. long and narrowing somewhat suddenly into the smooth stiff awn, shorter than itself. Indications of a tooth at each side of the base of the awn. Caryopsis somewhat flattened, thin and long, barge-shaped, 8-10 × 1·5-2 mm., pointed at both ends, brown, hairy at the tip with the remains of the stigma. “Seed” often purplish. Rachilla long and slender.

Must be carefully distinguished from _Brachypodium_, which has the
palea less inrolled and a stouter rachilla.

_Bromus giganteus_ has a shorter and flatter “seed” and longer awn.

_Bromus asper_, Murr. (Fig. 71).

Palea often reddish, 5-7 ribbed and usually roughly hairy, mid-rib scaberulous, about 15 mm. long, linear-lanceolate (barge-shaped), the tip more distinctly two-toothed and tapering more gradually into the smooth awn, about its own length. Rachilla distinct. Otherwise resembling _B. erectus_.

_B. giganteus_ has a shorter “seed” and longer awn.

ΔΔ _Palea scarcely hairy: awn up to twice its length._

_Bromus sterilis._
_B. giganteus._

_Bromus sterilis_, L. (Fig. 50).

Palea nearly smooth, somewhat inrolled, terete-lanceolate-acuminate, tough, red-brown, 12-15 mm. long, seven-ribbed, with a long serrulate awn (20-30 mm. or more) practically terminal. Ribs serrate. Caryopsis 9-10 mm. long, flattened, thin. Rachilla distinct, smooth, much wrapped in, widens upwards and is somewhat flattened.

The very slender and long “seed” and caryopsis distinguish this from
all but _B. erectus_, which has a shorter awn. Perhaps the awn is
truly terminal: if so it should go with _Festuca Myurus_, &c. (see p.
171). The length varies greatly.

_Bromus giganteus_, L.

Palea 7 mm. long and inrolled, the base and rachilla bristly, indistinctly 5-7 nerved, the tip bifid: sub-terminal awn serrulate, 12-15 mm. long.

Caryopsis 4·5 mm. long, flattened, thin, glabrous.

The caryopsis is shorter and more ovoid than in other Bromes.

≡≡ _Palea expanded above (coracle-shaped), awn from
sinus between two blunt or triangular teeth._

_Bromus arvensis._

_Bromus arvensis_, var. _mollis_, L. (Fig. 73).

Palea oblong or obovate, somewhat flattened above (coracle-shaped), distinctly 5-7 ribbed, 8-9 mm. long, not hairy, though the ribs may be ciliate. Awn smooth, arising from the depression between two teeth or rounded projections. Caryopsis flattened and thin, 6 × 1·5 mm.; apt to fall loose from the paleæ.

In the variety _B. secalinus_ the awn is usually shorter than the
elliptical palea, and originates in the sinus of a notch (Fig. 74):
in _B. mollis_ from between two teeth, and is as long as the obovate
palea.

_Bromus maximus_ and _B. madritensis_ are both rare.

The broader nerved paleæ of _B. mollis_ and shorter, fatter
caryopsis, as well as the longer awn distinguish it from _B.
secalinus_ and _B. arvensis_. In the other Bromes the palea is more
inrolled and the “seed” more slender as a rule. The rachilla is
usually bent above into a slight kink.

The Bromes are an extremely difficult group. The awn is inserted
between the two teeth of the palea or just below. The palea smooth or
ciliate on the nerves or roughly hairy. The fruit is flattened in
the antero-posterior plane, and usually shines through the closely
investing palea. A rachilla is visible. In _Brachypodium_ the
caryopsis is less flattened, and the apex tapers into the awn without
teeth. In _Lolium_ and _Agropyrum_ the caryopsis is still more
wheat-like and grooved.

All our Bromes are weeds, but some of them are important adulterants,
requiring careful examination.

_B. inermis_ is cultivated, and is a valuable grass. Awn short or
wanting. Paleæ strongly 5-7 ribbed, inner with a marked central rib,
closely adhering to caryopsis.

_B. Schraderi_ is also said to be valuable.

†† Caryopsis not thin and flattened, corn-like, 3·5-5 mm.
Palea smooth, inflated, boat-like.

_Lolium temulentum._

A weed of cultivation, said to be poisonous to cattle, a possible
explanation of which may be found in a fungus recently discovered as
a very constant inhabitant of the tissues under the seed coats.

_Lolium temulentum_, L. (Fig. 48).

Palea ovate, 6-7·5 × 2·5 mm., papyraceous, inflated, smooth, the tip dry and emarginate with a slender sub-terminal awn its own length or longer. It tends to adhere to the fruit. Fruit 3·5-5 mm. × 2·5 × 1·5, somewhat depressed. Rachilla large, cylindrical and smooth.

_L. perenne_ has no awn, or the merest trace of one. “Seed” 10-12
mm. long. Boat-shaped. Palea yellow, three-nerved, margins papery.
Rachilla flat, see p. 143.

** Awn terminal, and with no evident teeth at its base.

≡ Palea not much inrolled, ovate-lanceolate to
linear-lanceolate, and therefore boat-or barge-shaped.

Δ _Very hairy._

_Brachypodium sylvaticum_, Beauv. (Fig. 72).

Palea ribbed and hirsute much like that of _Bromus asper_, but straw-coloured, shorter (10-12 mm.), linear-lanceolate, more boat-shaped, and tapering without teeth into the longer (10-13 mm.) hairy awn. Caryopsis 7-8 mm., less flattened than in _Bromus_, with a shallow groove. Rachilla smooth.

_B. pinnatum_ (p. 171) has a much shorter awn, and is nearly glabrous.

These grasses are weeds, but are said to occur frequently as
adulterants.

ΔΔ _Glabrous or nearly so._

++ _Palea five-nerved, pubescent._

_Agropyrum caninum._

_Agropyrum repens_ is also often awned and may be described here (see
also p. 150).

_Agropyrum repens_, Beauv. (Fig. 76).

Palea tough, 10-12 mm. long, ovate-lanceolate, 3-5 ribbed and smooth; with a short (2-3 mm.) or long (8 mm.) terminal awn or a mere tooth. Rounded back. Fruit grey-brown, ciliate above, 5-6 × 1·4 × 0·7-0·9 mm., depressed, hardly grooved, adhering to the palea. Rachilla smooth or not, and narrowed below.

A noxious weed (see p. 150) and hence should be carefully excluded
from “seeds.”

_A. caninum_, Beauv., has a longer (10 mm. or more) and rougher awn, and is smaller (about 8 mm.), but otherwise very similar. Palea smooth except at the five-nerved apex. Rachilla thickened above, and hairy (Fig. 75).

_Elymus_ differs from _Agropyrum_ in its harder velvety palea,
no awn, and its club-like velvety rachilla. It is also larger
altogether, as a rule.

++++ _Palea seven-ribbed, smooth._

_Brachypodium pinnatum._

_Brachypodium pinnatum_, L., is similar, but the palea more open and boat-like and narrows more suddenly above into the smooth awn which is shorter than itself (Fig. 77). Length 8-9 mm. The caryopsis is, however, much more slender than in _Agropyrum_.

For distinction from _B. sylvaticum_, see above. The inner palea is
ciliate and more delicate than in _Agropyrum_.

≡≡ Paleæ rolled round the “seed” which is terete and
tapering gradually into a stiff awn.

Δ _Awn longer than the palea._

_Festuca Myurus._

See also _Festuca ovina_, _Cynosurus_, &c., p. 147, and _Arundo_.

_Festuca Myurus_, L. (Fig. 80).

“Seed” 5-7 mm. without the long (10 mm.) awn, tapering and slender (like _Nardus_), grey or brown. Finely mamillate upwards. Rachilla small.

ΔΔ _Awn shorter than palea._

_Festuca ovina_ (var. _rubra_).
_Nardus stricta._

_Aira flexuosa_, _Molinia_ and other moor-grasses occur with these
narrow-leafed Fescues, but are easily distinguished: _Molinia_ by
having no awn and being shorter and stouter, and _Aira flexuosa_ by
the dorsal awn and basal hairs.

_Festuca rubra_, L. (Fig. 78).

“Seed” pale brown with rosy tinge, 3-5 mm. long without the awn, smooth, or slightly hairy upwards. Caryopsis 2-3·5 mm., compressed, with a shallow broad flat furrow on the ventral face and a median long “hilum.” Rachilla cylindrical, smooth, dilated above.

The variety _F. heterophylla_ has narrower and longer “seeds,” and a hispid rachilla. Palea 5-6 mm.: caryopsis 3·5-4·5 mm. (Fig. 79).

Perhaps _Bromus sterilis_ should also come here (see p. 165).

With regard to these Fescues the student may note that _F. ovina_,
var. _tenuifolia_, has the smallest (4-5 mm.) and most ovoid “seeds,”
usually golden brown in colour. _F. rubra_ is darker and larger (5-6
mm.), as is also _F. duriuscula_ (6-7 mm.): the latter is also
narrower, with toothed palea, tapering suddenly at the base and more
awned. _F. heterophylla_ is much like _F. duriuscula_, but the palea
less toothed, and it tapers gradually at the base. The whole group is
very difficult, and needs attention.

_Nardus stricta_, L. (Fig. 81).

Outer palea tough and fused, 10-12 mm. long, narrow, lanceolate and tapering gradually into the stiff, serrulate, terminal awn shorter than itself. Inner palea minutely toothed at the apex and without awn, loosely enclosing the red-brownish yellow to bluish grey fruit which has no groove. “Seed” 4-6 mm. × 0·6 × 0·5 (without the awn), more or less triangular in section and serrulate on angles above.

BIBLIOGRAPHY.

BENTHAM AND HOOKER, _British Flora_, London, 1896.

BONNIER and LAYENS, _Nouvelle Flore de France_, Paris, 1887.

BRUNS, _Der Grasembryo_ in _Flora_, 1892, vol. LXXVI.

BURCHARD, _Die Unkrautsamen der Klee-und Grasarten_, Berlin, 1900.

DARWIN, _Power of Movement in Plants_, London, 1880.

DUVAL JOUVE, in _Mémoires de l’Acad. des Sciences de Montpellier_,
1871, vol. VII.

FREAM, _Elements of Agriculture_, London, 1892.

GROB, in _Bibliotheca Botanica_, H. 36, 1896.

GUÉRIN, _Recherches sur le développement du Tégument &c. des
Graminées_ in _Ann. d. Sc. Nat._ 1899.

GÜNTZ, _Unters. ü. d. anatomische Structur d. Grasblätter_, Leipzig,
1886.

HACKEL, in Engler’s _Natürliche Pflanzenfamilien_, II. Th. 2 Abth.
1887.

HARZ, _Landwirthschaftliche Samenkunde_, Berlin, 1885.

HOLZNER, _Beitr. zur Kenntn. d. Gerste_, Munich, 1888.

_Index Kewensis_, London, 1893-95.

JACKSON, _A Glossary of Botanic Terms_, London, 1900.

KIENITZ-GERLOFF, _Botanik für Landwirte_, Berlin, 1886.

NOBBE, _Handbuch der Samenkunde_, Berlin, 1876.

PARNELL, _British Grasses_, London, 1845.

PÉE-LABY, in _Annales des Sc. Naturelles_, 1898, vol. VIII.

PERCIVAL, _Agricultural Botany_, London, 1900.

PFITZER, in Pringsh. _Jahrb. f. wiss. Bot._ B. VII.

SCHMID, in _Bot. Centralbl._ 1898, B. LXXVI.

SCHWARZ, _Forstliche Botanik_, Berlin, 1892.

SCHWENDENER, in _Sitzungsber. d. Akad. Berlin_, 1889 and 1890.

SETTEGAST, _Die landwirthschaftl. Sämereien u. d. Samenbau_, Leipzig,
1892.

SINCLAIR, _Hortus gramineus Woburnensis_, London, 1824.

SOWERBY, _The Grasses of Great Britain_, London, 1861.

STEBLER and SCHROETER, _The Best Forage Plants_, London, 1889.

SUTTON, _Permanent and Temporary Pastures_, London, 1886.

TRIMEN, Article _Grasses_, in _Encyclopædia Britannica_, 9th ed.

VAN TIEGHEM, _Morphol. de l’embryon &c. chez les Graminées_ in _Ann.
des Sc. Nat._ 1897.

VESQUE, _Traité de Botanique Agricole &c._ 1885.

WARMING, _Lehrb. d. Oekologischen Pflanzengeogr._ Berlin, 1896.

WITTMACK, _Gras- und Kleesamen_, Berlin, 1873.

FOOTNOTES:

[Footnote 1: Some foreign grasses (_Andropogon_, _Panicum_, &c.) have solid stems, and in _Psamma_ and some others the lower parts may be solid.]

[Footnote 2: Leaf-stalks occur in tropical Bamboos.]

[Footnote 3: Tropical Bamboos branch in the upper parts and are woody. _Dinochloa_ and _Olyra_ are climbing grasses.]

[Footnote 4: Except, of course, in cases of virgin ground rapidly occupied by the seedlings.]

[Footnote 5: The most marked exceptions are the lemon-scented grasses (especially _Andropogon_) of India and Ceylon.]

[Footnote 6: The pale flanking lines seen in many grasses on each side of the mid-rib are the series of motor-cells referred to on p. 25.]

[Footnote 7: They may have short microscopic asperities, but there are no distinct long hairs.]

[Footnote 8: Very like a Poa when opened out, but the leaves are scabrid at the sheaths.]

[Footnote 9: Strictly speaking a spike is an axis bearing sessile _flowers_--not sessile _spikelets_: in Grasses, however, the conventional abbreviated term is sanctioned by long usage. The same applies to the panicle, &c.]

[Footnote 10: See note, p. 87.]

[Footnote 11: See note, p. 87.]

[Footnote 12: This term does not necessarily imply any botanical relationship with the true Millets (_Panicum_), but merely that the caryopsis is short and broad as in these grasses.]

[Footnote 13: In cases where the “seed” has fallen from the glumes the sample will usually show some of the latter lying loose.]

INDEX,

GLOSSARY AND LIST OF SYNONYMS.

Figures in bold type (+25+) refer to pages whereon the species or subject is more particularly dealt with; figures in italics (_25_) refer to pages containing illustrations.

Achene, 123

Acicular--bristle-like

Acuminate--tapering to a long point, 21, 139, 146, 147

Acute--simply pointed, 19, 21

Adaptations, 20, 24, 36, 37, 70, 124, 125, 132

Adventitious roots, 8, 131

Agriculture, 2, 3

_Agropyrum_--Wheat-grass, 11, 14, 22, 25, 26, 36, 49, 50, 51, 57, 69,
88, 90, 91, +106+, 107, 108, 144, 150, 167, 170, 171;
_A. caninum_, 7, 21, 28, 34, +57+, +80+, 92, +107+, 150, 168, _169_,
+170+;
_A. junceum_--var. of _A. repens_, 21, 29, 33, 35, 36, 57, _66_,
+81+, 102, 107;
_A. repens_, 7, 30, +57+, +80+, 81, 93, 102, +106+, 149, +150+,
_169_, +170+

_Agrostis_--Bent-grass, 7, 15, 22, 25, 49, 50, 51, 52, 53, 57, 82,
88, 89, 91, 103, +104+, 105, 112, 118, 125, 136, 137, 141, 144, 145,
159, 160, +161+;
_A. alba_, 7, 11, 13, 14, 28, 29, 32, 33, 34, 51, 52, 69, 92, +104+,
144, +145+, 162;
_A. canina_, 7, 11, 20, 28, 29, 37, 51, 52, +104+, 161, +162+;
_A. setacea_, 31, 104, 161, +162+;
_A. Spica-venti_, 31, 104, _130_, 161, +162+;
_A. stolonifera_--var. of _A. alba_, 14, +51+, 52, 104, +145+;
_A. vulgaris_--var. of _A. alba_, 29, 51, 52, 66, 104, +145+

_Aira_--Hair-grass, 6, 20, 21, 36, 48, 88, 89, 90, 91, 103, 104, 105,
106, 110, 112, +117+, 118, 125, 127, 138, 141, 144, 145, 159, 162;
_A. alpina_--var. of _A. cæspitosa_;
_A. canescens_, 8, 11, 14, 32, +47+, 66, 78, 91, 112, +159+;
_A. caryophyllea_, 8, 10, 14, 29, 32, +46+, +118+, +160+;
_A. cæspitosa_, 6, 11, 14, 22, 23, 25, 28, 33, 37, 41, +47+, 48, 63,
_65_, 68, 69, +77+, 104, 106, +117+, _128_, 160, +161+;
_A. flexuosa_, 7, 11, 14, 29, 33, 34, +46+, 68, 70, _71_, +79+,
+118+, 158, +160+, _161_, 171;
_A. montana_--var. of _A. flexuosa_;
_A. setacea_--var. of _A. flexuosa_;
_A. præcox_, 8, 10, 29, 30, 32, +47+, 91, +112+, 160

Air-spaces, 21, 39, 40, 62

Aleurone layer, _121_, _122_, 123

_Alopecurus_, 25, 53, 55, 88, 89, 90, 93, +101+, 109, 110, 119, 124,
152, 153, 155;
_A. alpinus_, 31, 101, 156;
_A. agrestis_, 7, 18, 30, 50, 52, 53, +101+, 155, +156+;
_A. bulbosus_--var. of _A. geniculatus_, 8, _9_, 156;
_A. fulvus_--var. of _A. geniculatus_, 156;
_A. geniculatus_, 7, _9_, 11, 14, 15, 28, 29, 33, 40, 48, 52, 53,
+101+, 155, +156+;
_A. pratensis_, 7, 11, 13, 14, _18_, 28, 32, 49, 50, 51, +52+, 55,
+82+, +101+, _155_, +156+

Alpine Foxtail--_Alopecurus alpinus_

Alpine Meadow-grass--_Poa alpina_

Alpine Poa--_Poa alpina_

Alps, 36, 37

_Ammophila--Psamma_;
_A. arundinacea_--_Psamma arenaria_

_Amphicarpum_, 120

Anatomy, 62-71, 95

_Andropogon_, 4, 27

Andropogoneæ, 122

Animal-distribution of seeds, 125

Animals killed by grasses, 127

Annual Beard-grass--_Polypogon monspeliensis_

Annual grasses, 10, 11, 37, 43, 59, 114

Annual Meadow-grass--_Poa annua_

Anther, _93_, 94, 119

Anthesis--the period of opening of the flower, 96

_Anthoxanthum_--Vernal grass, 11, 13, 22, 26, 27, 36, 56, 58, 60, 83,
_87_, 88, 90, 91, 94, 97, 110, 119, 124, 136, 152, _154_;
_A. odoratum_, 7, 28, 32, 33, 34, +57+, +76+, +102+, +103+, +154+;
_A. Puelii_, 67, 154

Anti-ligular peg, 41

_Apera--Agrostis_;
_A. Spica-venti_--_Agrostis Spica-venti_

Apex of leaf, 19, +21+, +22+

Apogamy, 134

Appressed hairs, 65

Aquatic grasses, 27, +28+, 39, 62, 103, 111, 112, 113

Arctic species, 37

_Aristida_, 36;
_A. hygrometrica_, 127

_Arrhenatherum_--False Oat, 6, 11, 13, 14, 17, 26, 32, 55, 56, 58,
60, 61, 66, 89, 90, 91, 92, 119, 152, 155, 157;
_A. avenaceum_, 6, 8, 25, 28, 33, 34, +56+, 66, +77+, _93_, +106+,
_129_, +157+

_Arundo_--Reed, 11, 14, 19, 20, 37, 40, 68, 69, 90, 91, 93, 103, 125,
130, 131, 139, 146, 171;
_A. Donax_, 21, 75;
_A. Phragmites_, 2, 6, 29, 32, 40, +51+, 55, 66, +75+, +138+

Asperities--minute stiff hairs giving roughness to the touch, 24, 45,
65, 66, 75, 77, 127

Auricles--ear-like projections at base of leaf-blade, 22, 133

_Avena_, _5_, 15, 21, 23, 47, 54, 56, 88, 89, 90, 91, 92, 95, 104,
106, +116+, 117, 125, 127, 138, 155, 157, _158_;
_A. alpina_--var. of _A. pratensis_;
_A. elatior_--_Arrhenatherum avenaceum_;
_A. fatua_, 28, 77, +117+, +156+, 157;
_A. flavescens_, 7, 11, 13, _18_, 26, 28, 56, +60+, 61, +81+,
+117+, +158+, 161;
_A. pratensis_, 7, 11, 14, 20, 21, 22, 25, 27, +47+, 56, 61, 63,
66, 81, +117+, 156, +157+;
_A. pubescens_--var. of _A. pratensis_, 16, 26, 27, 32, 33, 56,
+61+, 68, +157+;
_A. strigosa_--var. of _A. fatua_

Aveneæ, 122

Awn, 91, 92, +95+, 99-118, +125+, _126_, 127, _128_, _129_, +130+,
_131_, 142, 144, 151, 153, 154, 159, 160, 162, 163, _164_, 166,
_167_, 168, _169_, _170_, 171, _173_

Awned grasses, +92+, 99-101, 102, 103, 104, 105, 106, 107, 111, 112,
113, 114, 115, 116, 117, 151-174

Awned Nit-grass--_Gastridium lendigerum_

Awnless Brome--_Bromus inermis_

Awnless grasses, +93+, 104, 105, 107, 108, 109, 110, 111, 112, 138-151

Awn-point, 114, 115, 116, _123_, 131, _150_

Ballast plants, 30

Bamboos, 1, 5, 6, 37, 38, 96, 97, 123

_Bambusa_, 96

Barge-shaped “seeds,” 128, 163, _164_, 168

Barley--_Hordeum_, 120, 132, +133+, 163

Barley-type of “seed,” 138, 162

Barren Brome--_Bromus sterilis_

Barren flowers, 86, 89, 90, 99, 100

Basal-awn, 92, _128_, _129_, 130, 159

Basal hair-tufts, 138, _158_, 159, 160, 161

Base of leaf, _18_, _19_, 20, 22

Bast-sclerenchyma, 70

Bearded Darnel--_Lolium temulentum_

Bearded Wheat-grass--_Agropyrum caninum_

Beard-grass--_Polypogon_

Bent-grass--_Agrostis_

Bent-grass--_Agrostis canina_

Bermuda grass--_Cynodon Dactylon_

Biennial grasses, 10, 43

Bifid--cleft into two teeth, 95

Bitter-tasting grasses, 58, 59

Blade of leaf, 17, _18_, _19_, 20, 22, _23_, _24_, 26

Blue Moor-grass--_Sesleria cærulea_

Boat-shaped “seeds,” 127, _128_, _129_, 138, 142, _143_, 144, 167,
168, _169_, _170_

Bœhmer’s Phleum--_Phleum Bœhmeri_

_Brachypodium_--False Brome, 11, 14, 20, 60, 70, 88, 90, +107+, 108,
109, 165, 167;
_B. pinnatum_, 7, 34, +61+, +78+, 93, +107+, 130, 168, _170_, +171+;
_B. sylvaticum_, 7, 26, 28, 33, 34, 60, +61+, 76, 78, 92, +107+,
128, _164_, +168+, 171

Bracteoles, 95, 96, 97

Bracts, 94, 97

Branching, 6, 11

Branching of inflorescence, 83

Bristle-grass--_Setaria_

Bristle-leafed Bent-grass--_Agrostis setacea_

Bristle-like leaves, _16_, 21, _24_, 45

Bristle Oat--_Avena strigosa_

Bristles, 67, 125, 130

_Briza_--Quaking-grass, 14, 16, 22, 25, 90, 91, 92, 104, 136;
_B. media_, 8, 11, 17, 27, 32, +45+, 66, +77+, +112+, +142+;
_B. minor_, 10, 17, +45+, 112, 142

Brome--_Bromus_, 166, 167

_Bromus_--Brome-grass, 6, 10, 14, 17, 26, 44, 51, 59, 61, 76, 90, 91,
92, 95, 103, 104, 107, +115+, 117, 144, 151, 168;
_B. Alopecurus_, 95;
_B. arvensis_, 7, 8, 11, 27, 30, 32, +43+, 44, +76+, 108, +115+,
128, +166+, _167_;
_B. asper_, 6, 11, 17, 20, 22, 26, 28, 33, 34, +43+, 44, 59, 76,
+115+, 116, _164_, +165+, 168;
_B. commutatus_--_B. racemosus_;
_B. diandrus_--_B. madritensis_;
_B. erectus_, 7, 11, 13, 14, +43+, 51, 70, 100, +164+, 165, 166;
_B. giganteus_, 6, 11, 28, 33, 34, +43+, 44, 51, 76, 82, +115+,
116, 165, +166+;
_B. inermis_, 13, 22, 31, +43+, 167;
_B. madritensis_, 31, 116, 166;
_B. maximus_, 31, 116, 166;
_B. mollis_--var. of _B. arvensis_, 8, 26, +43+, 44, 108, 115, 143,
+166+, _167_;
_B. multiflorus_--var. of _B. arvensis_;
_B. racemosus_--var. of _B. arvensis_;
_B. Schraderi_, 167;
_B. secalinus_--var. of _B. arvensis_, 115, 166, _167_;
_B. sterilis_, 7, 11, 27, 30, 32, +43+, 44, +76+, +116+, _131_,
+165+, 172

Brown Bent--_Agrostis canina_

Buds, 12

Bulbous Meadow-grass--_Poa bulbosa_

Bulbous Poa--_Poa bulbosa_

Bulbs, 8, 37, 114

_Calamagrostis_--Small reed, 29, 40, 88, 89, 125, 138;
_C. Epigeios_, 31, 70, 78, +103+, +159+;
_C. lanceolata_, 31, 66, 103, +138+;
_C. strigosa_, 103, 159;
_C. stricta_, 31, 103, 159

Canary grass--_Phalaris canariensis_

Carpel, 97, 121

Caryopsis--the true fruit of the grass, _121_, _122_, 123, 124, 127,
_128_, 132, +134+, 135

_Catabrosa_--Whorl-grass, 14, 21, 23, 29, 40, 63, 84, 88, 90, 91, 92,
104, 105, 118, 146;
_C. aquatica_, _12_, 25, 31, 73, +112+, 142

Cat’s-tail grass--_Phleum_

Cat’s-tail type of inflorescence, 100

Cells, 65

Cereals, 1

Chaff, 85, 134

Chalk-fleeing, 35

Chalk species, 27, +32+, 35

_Chamagrostis_--_Mibora_

Chlorophyll, 2, 62, 70, 72, 73, 95

_Cinna_, 97

Circular shoot sections, _16_, 43

Classification according to anatomical characters of leaf, 72-82

Classification according to floral characters, 97, 99-118

Classification according to characters of seed, 135-174

Classification according to vegetative characters, 39-61

Classification of seedlings, 133

Clay species, 32

Cleistogamous--when pollination and fertilisation are completed in
flowers which do not open, 120

Climbing grasses, 6

Close panicle--an inflorescence in which the primary branches do not
diverge widely from the rachis, 110

Cock’s-foot--_Dactylis glomerata_, 83

Cockspur Panicum--_Panicum Crus-galli_

Collar, 58, 123

Coloured nodes, 15

Coloured sheath, 18

Coma, 125

Common Cat’s-tail--_Phleum pratense_

Common Dog’s-tail--_Cynosurus cristatus_

Common Foxtail--_Alopecurus pratensis_

Common Mat-grass--_Nardus stricta_

Common Quaking-grass--_Briza media_

Common Reed--_Arundo Phragmites_

Compact Brome--_Bromus madritensis_

Composites, 2, 125

Compressed shoots, 15, _16_, 40, 41, 48, 53

Conduplicate--folded, 15, _16_, 20, 63

Convolute--inrolled, 15, _16_, 63

Copses, grasses of, 28, 34

Coracle-shaped “seeds,” 128, _137_, 166, _167_

Cord-grass--_Spartina stricta_

Coriaceous--leathery, 21

Corn, 1

Corn-field species, 28

Corn-type of fruit, 136, 138, 167

_Corynephorus canescens_--_Aira canescens_

Cotton-grass--_Eriophorum_

Couch-grass--_Agropyrum repens_.
_See also_ Twitch, 150

Creeping Fescue--_Festuca rubra_

Creeping grasses, _12_, 13, 14, _15_

Creeping grass-seeds, 127

Creeping Soft-grass--_Holcus lanatus_--_Holcus mollis_

Creeping stem, 12

Crested Dog’s-tail--_Cynosurus cristatus_

Crested Kœleria--_Kœleria cristata_

Cross-breeds, 120

Cross-fertilisation, 119, 120

_Crypsis_, 123

Culms, 14, 37, 83

Curved Lepturus--_Lepturus incurvatus_

Cuspidate--ending suddenly in a short point, 135

Cut-grass--_Leersia_

Cuticle, 68, 70

Cutinized, cuticularized--impregnated with corky substance, 64

Cylindrical inflorescence, 90

Cylindrical “seed,” _173_

_Cynodon_--Dog’s-tooth grass, 14, 65, 67, 69, 87, 90, 105;
_C. Dactylon_, _15_, 31, +72+, 137

_Cynosurus_--Dog’s-tail, 14, 18, 25, 49, 50, 52, 81, 88, 89, 90, 93,
103, 130, _148_, 151, 171;
_C. cristatus_, 7, 11, 13, _23_, 28, 32, +50+, +80+, +108+, 147,
+148+;
_C. echinatus_, 100, 108

_Dactylis_--Cock’s-foot, 11, 13, 14, 16, 20, 26, 41, 63, 83, 88, 89,
90, 91, 93, 103, 148, 158;
_D. glomerata_, 7, _16_, 17, 27, 32, 33, 34, +41+, 65, 66, 69,
+74+, +109+, 149, _150_, +151+

Darnel--_Lolium perenne_--_Lolium temulentum_

Decumbent Heath-grass--_Triodia decumbens_

Dehiscent fruits, 123

Depauperated--starved and consequently dwarfed, 109

_Deschampsia cæspitosa_--_Aira cæspitosa_

_Deschampsia flexuosa_--_Aira flexuosa_

_Digitaria_--_Panicum_

Digitate--spread out like fingers, _15_

_Digraphis_--Reed-grass, 6, 11, 13, 26, 40, 41, 51, 55, 69, 73, 75,
90, 91, 92, 103, 131, 139, 146, 159;
_D. arundinacea_, 6, _16_, _23_, 29, 32, +54+, 64, +75+, +103+,
+139+, 150

Dimensions of grasses, 6

_Dinochloa_, 6

Diœcious, unisexual, the male and female flowers being on separate
plants, 119

Disarticulation of fruits, _124_

Dissemination, 125, 127

Distichous--in two ranks on the axis, 106

Distribution of grasses, 2, 37, 38

Distribution of seeds, 124-127

Distribution of sexes, 119

Ditches, grasses of, 28, 29

Dog’s-tooth grass--_Cynodon Dactylon_

Dorsal awn, 92, 112, 116, 130, 159

Double seed--grass “seed” where the remains of a second flower come
away with the first, _152_, _153_

Downs, grasses of, 29

Downy Oat--_Avena pubescens_

Dry leaves, 21

Dry situations, 24, 26, 29

Dry soils, 29, 32

Duration, 10

Dwarfed species, 6

Early Hair-grass--_Aira præcox_

Ears, _19_, 22, 57, 59

_Echinochloa_--_Panicum_

Effects of grasses on soil, 35, 36

Egg-cell, 121

_Eleusine_, 123

Elliptical shoot-section, 16, 44

_Elymus_--Lyme-grass, 6, 13, 14, 21, 22, 25, 36, 48, 57, 63, 65, 69,
79, 90, 92, 102, 170;
_E. arenarius_, 6, 29, 33, 35, 36, +48+, 66, _67_, +108+, +149+,
_150_

Embryo, 121, 131, 133

Embryo-sac, 121

Embryonic bud--plumule, 123

Embryonic roots, 123, 133

Endosperm, 120, _121_, _122_, 123

Energy stored in leaves, 2, 3

Entire--not cut: with unbroken outline, 19

Entire sheath, 17

Entire-sheathed grasses, 17, 39, 113, 115

Epidermis, 25, 36, 62-67, 70, 76, _122_

Equitant--one folded leaf straddling over another, 39, 41

_Eriophorum_, 3

Extra-vaginal shoots, 12

False Oat--_Arrhenatherum avenaceum_

Female flowers, 89

Fertile flowers, 86, 89, 90

Fertilisation--the fusion of the nucleus of the pollen-tube with that
of the egg-cell, 121

Fescue--_Festuca_, 115, 130, 137, 144, 148, 151, 172

_Festuca_--Fescue, 2, 6, 7, 15, 21, 25, 36, 49, 51, 53, 90, 91, 92,
108, 109, 110, 113, 114, 116, _124_, 144, _147_;
_F. arundinacea_--var. of _F. elatior_, 144, 151;
_F. calamaria_--_F. sylvatica_;
_F. duriuscula_--var. of _F. ovina_, 46, _69_, +78+, 80, 147, 172,
173;
_F. elatior_, 6, 7, 11, 13, 14, 18, 19, 22, 25, 28, 32, 44, +50+,
51, 63, _64_, 82, _84_, 108, 111, 115, +116+, 128, 131, _143_,
+144+;
_F. gigantea_--_Bromus giganteus_;
_F. heterophylla_--var. of _F. ovina_, 13, 46, 69, 71, 78, 80, 147,
+172+, 173;
_F. uniglumis_, 31, 92, 111;
_F. loliacea_--var. of _F. elatior_, 90, 108;
_F. Myurus_, 8, 10, 14, 19, 20, 28, +46+, 90, 91, 92, 99, +111+,
115, 130, 166, +171+, _173_;
_F. ovina_, 7, 8, 11, 13, 14, _19_, 20, 22, _24_, 28, 32, 33, 36,
+45+, 46, 68, 69, 70, +79+, +111+, 112, 115, +116+, 134, +147+,
151, 171, _172_;
_F. pratensis_--var. of _F. elatior_, 7, _19_, _24_, 49, 63, _64_,
_84_, 111, _143_, +144+;
_F. procumbens_--_Poa procumbens_;
_F. rigida_--_Poa rigida_;
_F. rubra_, var. of _F. ovina_, 7, 13, 14, 18, _24_, 33, 46, 69,
78, 80, 147, 151, +171+, _172_;
_F. sabulicola_--_F. rubra_, 46;
_F. sciuroides_--var. of _F. Myurus_, 25, 26, 46;
_F. sylvatica_, 6, 11, 14, 28, 34, +116+, _131_, 147;
_F. tenuifolia_--var. of _F. ovina_, 46, 148, 172;
_F. vivipara_--var. of _F. ovina_

Festuceæ, 122

_Fibichia umbellata_--_Cynodon Dactylon_

Fibrous roots, 8

Fibrous Twitch--_Agropyrum caninum_

Field Brome--_Bromus arvensis_

Filament, 94

Fine Bent--_Agrostis vulgaris_

Finger-grass--_Panicum glabrum_

Fiorin--_Agrostis alba_

Firing, 35, 38

Flanking lines, 41, 53, _63_, 73, 74

Flat leaves, 20, 47, 77

Flat shoots, 15, _16_, 20

Flattened Meadow-grass--_Poa compressa_

Flavour, 27

Fleshy fruits, 123

Floating leaves, 39

Floating Foxtail--_Alopecurus geniculatus_

Floating Meadow-grass--_Glyceria fluitans_

Floating Sweet-grass--_Glyceria fluitans_

Floral diagram, _94_, 95, _96_

Flower, 83, _84_, _85_, +86+, _87_, 89, 90, _93_, _94_, 95, _96_, 97,
99, 105, 106, 112

Flowering glume--the outer palea

Flowering stem, 83, 84

Flying Bent--_Molinia cærulea_