GRASSES GROUPED ACCORDING TO THEIR FLOWERS AND INFLORESCENCES.
I. GRASSES WITH ONLY ONE PERFECT FLOWER IN THE SPIKELET.
+(1) Inflorescence spikate[10].+
+A. Inflorescence a spike of simple spikelets.+
_Nardus stricta_, L. A tough wiry tufted moor-grass, with setaceous
leaves, secund spikelets with a single rudimentary glume, and a stiff
simple hairy style. (Fig. 2.)
The much rarer _Mibora verna_ about three inches or so high, and
_Lepturus_, both with flat leaves, also come here.
Certain superficial resemblances in the habit or inflorescence in
_Festuca Myurus_ and rare forms like _Spartina_, may occasionally
cause hesitation until the spikelets are examined.
+B. Spike with sessile or sub-sessile tufts of three or more
spikelets.+
(_a_) A spike of tufted awned spikelets, in triplets at each
notch of the rachis, and one or two of each triplet barren.
+Hordeum.+
No other genus of our grasses is like _Hordeum_. The purely
superficial resemblances in the inflorescences of _Polypogon_,
_Lagurus_, and _Cynosurus echinatus_--all extremely rare
species--disappear at once on examination.
In _Bromus erectus_ the equally superficial resemblance is due to the
stiff awns: the spikelet has six to twelve flowers and is stalked.
It should also be noted that _Hordeum sylvaticum_ occasionally has a
rudimentary second flower in the lateral spikelets (see note p. 105).
(α) A shade-grass with the central spikelet only imperfect;
staminate, or rudimentary, or entirely wanting.
_H. sylvaticum_, Huds.
(β) The central spikelet is the perfect one, the two lateral
barren. Growing in open land.
(i) _A perennial meadow-grass. All the glumes scabrid and
bristle-like._
_H. pratense_, Huds.
(ii) _Annuals with some of the glumes at least, lanceolate
or broad below._
* _Ruderal plant, with cylindrical spikes, long awns; glumes
of the central flower dilated below._
_H. murinum_, With.
** _Maritime plant, more or less glaucous, with short ovoid
spikes: glumes of the central flower bristle-like._
_H. maritimum_, With.
(_b_) Spike cylindrical, of sessile or nearly sessile awned
spikelets, densely crowded round the axis, the whole resembling
a fox’s brush or cat’s tail.
Species of _Lagurus_, _Polypogon_, _Phalaris_ (not truly awned),
_Panicum_ (with bristles between the spikelets), and _Gastridium_ are
other British grasses approaching this type of inflorescence: they
are all rare or very local.
_Sesleria_ has an ovoid spike, but the spikelets are two-flowered and
not truly awned.
_Kœleria_ may present resemblances, but the spikelets are very
different in detail (see p. 109).
(i) _Awns inserted into the back of the single palea,
and hair-like. Glumes connate below, keeled. Only
one palea._
+Alopecurus.+
* _Annual corn-weed, with a long and slender spike,
pointed above. Glumes almost glabrous, and connate
to the middle._
_A. agrestis_, L.
** _Perennials, with shorter and stouter spikes, rounded
above. Glumes connate at the base only, and obviously
hairy on the keel._
† _Procumbent and kneed at the nodes below.
Spike 1-2 inches long. In marshy places._
_A. geniculatus_, L.
†† _A meadow-grass, with erect stems, and spikes
2-3 inches or more and stouter._
_A. pratensis_, L.
The rare _A. alpinus_, Sm. with short ovoid spikes, about one inch
long, only occurs in the Highlands.
(ii) _Awns, when present, merely the stiff, pointed
termination of the keel. Glumes free below. Paleæ two._
* _A glaucous shore plant with long creeping stolons
(sand-binder). Inflorescence harsh, 5--6 inches long.
Glumes tapering, simply acute._
_Psamma arenaria_, Beauv.
_Elymus_, a much rarer sand-binder of similar habit, may lead to
confusion until the 3--4 flowered spikelets and different arrangement
are observed. (See p. 108.)
_Agropyrum repens_ (var. _junceum_) is similar in habit and station,
but its spikes and spikelets are very different (see p. 107).
_Phleum arenarium_ is much smaller (see below).
** _Erect. Inflorescence rarely longer than three inches.
Spikelets flat: glumes keeled, the keel suddenly produced
into a sharp stiff awn or mucronate point. Paleæ two._
+Phleum.+
† _Tall perennial meadow-grass. Awn bristle-like, almost
as long as the nearly glabrous glume: spike long,
cylindrical._
_P. pratense_, L.
†† _Small, compact annual shore plant, with the glumes
acute only and the keel ciliate above. Inflorescence
not more than 1--1-1/4 inch long._
_P. arenarium_, L.
The rare _P. Bœhmeri_, Schrad. has the glumes merely tapering to a
sharp point; and the rare _P. alpinum_, L. has a much shorter spike
and glumes ciliate on the keels.
The rare _P. asperum_, Jacq. has broad, shortly mucronate glumes and
a longer and more slender spike.
+(2) Inflorescence a panicle--i.e. tufts or spreading stalked groups
of spikelets are arranged on the main axis.+
+A. Inflorescence compact and irregular; a spike of tufts
(spike-like panicle). Glumes four, the inner pair awned: paleæ
minute. Stamens two only.+
_Anthoxanthum odoratum_, L.
The four glumes and two stamens distinguish this grass at once. Other
grasses with occasionally tuft-like inflorescences--e.g. species of
_Agrostis_, _Gastridium_, _Aira_, _Dactylis_, _Cynosurus_, _Poa_,
_Triodia_, _Kœleria_--are distinguished at once by having three
stamens (_Bromus_ occasionally has but two), only two glumes, several
flowered spikelets, &c.
+B. Inflorescence a distinctly branched panicle, more or less loose
and spreading.+
(_a_) Tall reed-like perennials, growing in water or in marshes,
with plume-like inflorescences, and silky hairs at the base
of the paleæ. Glumes with a keel and point, but not awned.
(i) Spikelets purplish: outer palea with a slender dorsal awn:
basal hairs longer than the paleæ. Leaves narrow. Not common.
_Calamagrostis Epigeios_, Roth.
(ii) Spikelets greenish. No awns: basal hairs much shorter than
the paleæ. Leaves broad. Common.
_Digraphis arundinacea_, Trin.
A variety of _Digraphis_ with white stripes in the leaves is grown in
gardens. Other aquatic reed-like grasses are _Arundo_ and _Glyceria
aquatica_: both have several flowers in the spikelet.
The rare _Calamagrostis lanceolata_, Roth., _C. stricta_, Nutt. and
_C. strigosa_, Hartm. also come here.
(_b_) Slender grasses, not reed-like, with delicate loosely
spreading panicles of small spikelets.
(i) A tall, slender shade-grass, in woods. Paleæ very smooth and
glistening. Spikelets few, distant and turgid, awnless.
_Milium effusum_, L.
_Melica uniflora_, also a wood-grass, has the spikelets two-flowered,
though the upper one may be a mere rudiment, and much fewer, on a
flexuous nodding axis. The much rarer _M. nutans_ has two perfect
flowers in the spikelet (see p. 105).
(ii) Grasses of open situations, with numerous small pointed
spikelets. Inner palea minute or absent.
+Agrostis.+
The genus most likely to give trouble here is _Aira_, which though
normally with two flowers in the spikelet, occasionally has but one.
As regards the common species of similar habit, &c., _Aira_ has
bristle-like leaves and _Agrostis_ flat ones.
Again, _Agrostis alba_ has no protruding awn, as in the spikelets of
_Aira_. For _Aira cæspitosa_ and other details, see p. 117.
* _Awnless, or at most a short bristle not equalling the palea.
Leaves flat and short._
_A. alba_, L.
An exceedingly variable plant. The variety _A. stolonifera_ has a
less spreading panicle, and broader leaves with a long serrated and
pointed ligule: the variety _A. vulgaris_ has a spreading loose
panicle, narrower leaves, and a short truncated ligule. There is,
however, much difficulty in distinguishing the intermediate forms on
mountain-pastures, &c.
** _Distinctly awned. Leaves narrower, the lower ones inrolled
and almost setaceous._
_A. canina_, L.
The rarer _A. setacea_, Curt. with subulate leaves and _A.
Spicaenti_, L. with long awns also come here.
The lax spreading type of panicle characteristic of _Aira_ and
_Agrostis_, &c., described above, occurs in species of _Avena_,
_Bromus_, _Briza_, _Poa_ and _Catabrosa_, but the basal silky
hairs and twisted awns (_Avena_), long sub-terminal bristle-awns
(_Bromus_), habit (_Catabrosa_), and the presence of two, three,
or more flowers in the considerably larger spikelets of all, easily
distinguish them.
The rare grasses _Leersia_, with two glumes and no paleæ, and
_Gastridium_, with curiously bullate bases to the glumes, also come
into this group with one-flowered spikelets, but their characters
must be studied with the flora. The same remark applies to species of
_Panicum_, _Cynodon_, _Spartina_ and other aliens, occasionally met
with.
II. GRASSES WITH AT LEAST TWO FLOWERS--OF WHICH ONE MAY BE
IMPERFECT--IN THE SPIKELET.
+A. Only one perfect flower, the other staminate only or altogether
rudimentary. Inflorescence a loose or racemous panicle.+
In _Hordeum sylvaticum_ the two lateral spikelets occasionally
conform to this heading (see p. 100), and the same is said to be the
case sometimes in _Aira_ (see p. 104). The rudiments are extremely
minute, however, and hardly suffice to justify the removal of these
grasses to this group.
In one or two species of _Aira_ the panicle may be somewhat
contracted and tuft-like.
The very rare _Hierochloe_ has one perfect flower, and two lower
staminate ones in each spikelet.
(_a_) A shade-grass found in woods. Awnless. One flower perfect,
the other (upper) reduced to a small stalked knob.
Inflorescence racemous.
_Melica uniflora_, L.
The much rarer _M. nutans_ has two perfect flowers and a similar
rudiment (see note, p. 104).
(_b_) Grasses of open situations, spikelets with awns. The reduced
flower staminate.
* Upper flower perfect, lower staminate only. Tall oat-like
meadow-grass, with a bent and twisted dorsal awn to the outer
palea of the lower flower: silky hairs at the base of paleæ.
_Arrhenatherum avenaceum_, Beauv.
The grasses most like this are species of _Avena_ and _Aira_. The
former have two or more perfect flowers, and the only broad-leafed
_Aira--A. cæspitosa_, see p. 117--is easily distinguished by its leaves
and its very small spikelets and short simple awns.
** Upper flower staminate: lower perfect. Small hairy grasses,
with red-veined basal leaf-sheaths and short simple awns.
+Holcus.+
† _Erect, evenly hairy, glumes blunt, awn not protruding.
Common._
_H. lanatus_, L.
††, _More or less procumbent, hairs chiefly at the nodes. Glumes
pointed. Awns simple and exserted. Rarer._
_H. mollis_, L.
+B. Each spikelet with at least two perfect flowers, often more.+
(+1+) +Inflorescence spikate, the main axis bearing sessile or
sub-sessile spikelets, each containing three or more flowers.+
(_a_) Spike simple[11], axis stout and notched, each notch having
one spikelet closely sessile in it.
(_i_) Spikelets distichous, the flat side of each--i.e. the edges
of the glumes--being next the axis (rachis).
+Agropyrum.+
* _A weed with creeping stolons, and no awns or mere points to
the glumes._
A. _repens_, Beauv.
The variety _A. junceum_ found as a sand-binder on sea-coasts is
glaucous, stiffer, with sharply pointed leaves, and blunt glumes. For
other sand-binders see note, p. 102.
** _Not creeping. Awns long and prominent._
_A. caninum_, Beauv.
(ii) The rounded backs of the glumes are next the rachis.
* _Spikelets flat and closely sessile in the notches of the
rachis._
+Lolium.+
† _Awnless or nearly so. Perennial._
_L. perenne_, L.
†† _With conspicuous awns. Annual, not common._
_L. temulentum_, L.
There are several cultivated varieties of _L. perenne_: _L.
temulentum_ is notoriously poisonous (see note, p. 168). The
lowermost glume of each spikelet is often alone developed or
conspicuous, and looks like a bract in the axis of which the
spikelet sits.
** _Spikelets elongated and hardly flattened, and not quite
sessile, especially the lower: rachis scarcely notched, the
spikelets with their sides (edges of glumes) next the axis._
+Brachypodium.+
† _A shade-grass with long, conspicuous awns to the more or less
drooping spikelets. Common._
_B. sylvaticum_, Beauv.
†† _Growing in the open. Spikelets stouter, stiffer and more
erect, with short awns. Not common._
_B. pinnatum_, L.
_Brachypodium_ may easily be confounded with _Bromus_, but the
spikelets are nearly sessile: their shape and the absence of
conspicuous notches distinguish this genus from _Agropyrum_.
_Lolium_ has a conspicuously notched rachis and the spikelets
arranged in the other plane.
_Poa loliacea_, Huds., an uncommon sea-shore weed, may also be
placed here; as also _Festuca elatior_, var. _loliacea_, Curt. and
some forms of _Bromus arvensis_, var. _mollis_, L.
No other British grasses resemble _Brachypodium_: any superficial
likeness remarked in species of _Hordeum_, _Festuca_, &c.
disappears at once on examination.
(_b_) Spike compound--i.e. with clusters of two or more sessile or
sub-sessile spikelets arranged along the rachis.
(i) Spike elongated, fertile spikelets with 3-5 flowers.
* _Pasture-grass with wiry rachis, on which the spikelets are
secund and sessile in clusters: in each cluster a comb-like
group of barren glumes subtends one of fertile spikelets._
_Cynosurus cristatus_, L.
The rare _C. echinatus_ has the pectinate groups of barren glumes
even more prominent.
** _Stout glaucous sand-binder with pairs of spikelets sessile
in the notches of the rachis, and all fertile. Spike
cylindrical. Not common._
_Elymus arenarius_, L.
For other sand-binders see p. 102. The only grass likely to be
confounded is _Agropyrum_, in which the spikelets are not paired.
_Lolium_, _Brachypodium_, &c. are easily distinguished.
(ii) Spike short and ovoid: spikelets sub-sessile and imbricate, in
clusters. Bluish.
_Sesleria cærulea_, Ard.
Not easily mistaken for any other grass. As some of the spikelets
are shortly stalked, the inflorescence is strictly paniculate, but
the fact is not obvious. The glume-like bract at the base of the
spike, and the general appearance suggest resemblances to certain
moor-sedges at first sight. The only other grasses with similarly
shaped spikes are species of _Alopecurus_, _Phleum_, and the rare
_Lagurus_, _Polypogon_, _Phalaris_, _Panicum_, all with very
different spikelets and easily distinguished.
(+2+) +Inflorescence a panicle or raceme--i.e. the spikelets on
evident stalks, simple or branched, from the main axis.+
It does not follow that every spikelet is distinctly stalked, and
cases occur where the stalks are very short and stiff: when this
happens to the stalks arising from the main axis, and the latter
is elongated, the type of the spike is closely approached, and the
inflorescence resembles that of _Brachypodium_, _Lolium_, &c. In
some depauperated varieties of _Poa_, _Festuca_, &c., an actual
spike results (see note, p. 111): the number of flowers in the
spikelet is important.
_a_) Panicle short, contracted and tuft-like, owing to the
shortness and stiffness of most of the stalks and their
tendency to remain erect, at least until anthesis. Glumes
keeled and ending in a point.
(i) _Panicle with a few branches, at first erect, ending in
tuft-like secund clusters. Spikelets harsh, with 3-5 flowers.
Coarse meadow-grass._
_Dactylis glomerata_, L.
Not easily confounded with any other grass if attention is paid to
the folded coarse leaves, the tufted perennial habit, and the harsh
inflorescence, the glumes on the spikelets being stiffly hairy on
the keel.
(ii) _Panicle contracted, more or less ovoid or cylindroid, but
most of the spikelets stalked, and not aggregated into dense
clusters, spikelets silvery, containing 2-3 flowers._
_Kœleria cristata_, Pers.
Any resemblances to forms of _Aira_ are at once nullified by
the absence of true awns in _Kœleria_. _Festuca_ and _Poa_ have
more numerous flowers in the spikelet. _Anthoxanthum_ has only
one flower, with two stamens, in the spikelets. _Phleum_ and
_Alopecurus_ present resemblances, but see pp. 101 and 102.
(_b_) Panicle elongated and lax--i.e. all or most of the spikelets
on distinct slender stalks, longer than themselves.
(i) _Panicle close: the spikelets on distinct and even long
stalks, but the latter erect and keeping the spikelets near the
main axis._
In some cases the stalks from the main axis bear only one spikelet
each and the type of inflorescence is that of a raceme; usually,
however, one or more of the lowermost stalks branch and disclose
the panicle.
* Panicle with few simple branches, racemous, each spikelet large
and containing about four flowers, palea three-toothed at the
apex. A small heath-grass, with hairs at the ligule.
_Triodia decumbens_, Beauv.
The inflorescence may have some resemblance to _Melica_ (see p.
105), but the four-flowered spikelet, ligule, habitat and stature
distinguish it at once.
** Panicle with divided branches, which are more or less erect.
† Spikelets awnless.
⊙ _Spikelets small, purplish, with two or at most three
florets; the upper on a stalk. Coarse moor-grass._
_Molinia cærulea_, Mœnch.
⊙⊙ _Spikelets with six or more florets._
‡ _Tall aquatic grass with long, lax, narrow panicle and
spikelets, somewhat nodding, and with 8-20 flowers in
each._
_Glyceria fluitans_, Br.
The only similar grass is _Glyceria aquatica_, Sm. which differs in its
more reed-like habit, open panicle, and fewer flowers.
‡‡ _Small land-plants not more than a foot high, with
short, stiff, somewhat crowded panicles, and spikelets
containing 6-8 flowers._
≡ _Maritime perennial with creeping stolons, and about a foot
high: panicle somewhat open below._
_Poa maritima_, Huds.
≡≡ _Inland plant with secund panicle, about six inches high._
_P. rigida_, L.
The rare _P. procumbens_, Curt. and _P. bulbosa_, L. also come
here, as well as starved forms of _P. compressa_, L. Some forms
of _Festuca elatior_, var. _pratensis_, Huds. growing in dry
situations may give trouble, and will have to be examined with the
flora. See also note, p. 109.
†† Spikelets awned.
⊙ _Awns bristle-like and terminal on the paleæ: flowers
about six in each spikelet. Leaves setaceous. Panicle
secund._
≡ _Awns long and bristle-like. An annual weed._
_Festuca Myurus_, L.
≡≡ _Awns very short, or merely the drawn out points of the paleæ.
Perennial._
_F. ovina._
The rare _F. uniglumis_, Soland., and some other varieties may also
come here.
Some forms of _F. ovina_ are viviparous (see p. 134), and several
varieties have to be distinguished.
⊙⊙ _Awns hair-like and dorsal on the paleæ. Flowers two
in each spikelet. Annual, six inches or less in height._
_Aira præcox_, L.
The rare _A. canescens_, L. also comes here: its awn is jointed and
with a minute tuft of hairs about the middle.
(ii) _Panicle lax and open, the fine hair-like branches spreading
widely during florescence, or even pendent or drooping._
* Spikelets awnless.
† A small aquatic grass with prostrate habit and two-flowered
spikelets with broad truncate glumes and paleæ.
_Catabrosa aquatica_, Beauv. (Fig. 4).
The two-flowered spikelets distinguish it at once from _Glyceria
aquatica_, to say nothing of its softer and smoother texture and
small stature. _Poa trivialis_ may have two flowers, but it is
an erect meadow-grass, with keeled and pointed glumes and paleæ.
_Aira_ and _Agrostis_ are awned, or differ entirely in habit.
†† Spikelets with at least three or four, but usually more
flowers.
⊙ _A perennial field-grass with few large, compressed,
bluntly triangular or ovate spikelets, dangling at the
end of capillary branchlets; with membranous, loosely
imbricated, concave and inflated paleæ and glumes,
and 6-8 flowers._
_Briza media_, L.
The much rarer _B. minor_, L. is an annual and smaller.
⊙⊙ _Spikelets small and numerous, more or less elongated and
pointed, not dangling: glumes and paleæ not inflated_.
_Poa_ and _Festuca_ (see p. 116) are difficult genera for the
beginner; several of the species vary considerably in detail.
Generally speaking the spikelets of _Festuca_ are hard, harsh
and sharply pointed, or with short or evident awns; in _Poa_
they are softer, and with blunter points, and never awned. The
most obviously awned species of _Festuca_ have more or less
setaceous leaves and contracted inflorescences (see p. 111). Some
of the mountain species of _Poa_ are extremely variable in small
characters.
≡ _Reed-like aquatic, with obtuse glumes rounded dorsally;
the large richly branched panicle bearing numerous 5-10
flowered spikelets. Sheath entire or nearly so. No we
to the paleæ._
_Glyceria aquatica_, Sm.
For other reed-grasses, see note, p. 103. _Glyceria fluitans_ has
a more contracted panicle and usually more flowers in the spikelet
&c. (see p. 111).
≡≡ _Meadow and pasture grasses &c., usually small. Glumes
more or less keeled and acute. Sheaths split_.
+Poa.+
‡ _Spikelets very small and containing 2-3 flowers only.
Stem slender, terete and rough; ligule long and acute,
palea with prominent lateral nerves._
_P. trivialis_, L.
The flowers are fewer than in any other _Poa_, and may be only two.
_P. nemoralis_, with 3-5 flowers, may also occasionally be found
with two only: it differs from others in its more acute glumes,
smooth stem and short ligule.
_P. pratensis_ differs in its creeping stolons, short ligule and
more numerous 4-5 flowers, and in the indistinct nerves of the
palea.
‡‡ _Spikelets 4-6 flowered._
≡ _Annuals, about six inches high, with relatively
large and numerous spikelets for so small a panicle.
No “web” at the base of the paleæ._
_P. annua_, L.
This is the small grass so common as a weed on road-sides and on
lawns, flowering even in winter. For other annual species of
_Poa_--_P. rigida_, _P. loliacea_ and _P. procumbens_--see note p.
108 and p. 111.
≡≡ _Perennials._
Δ _With creeping stolons._
_x Stems and leaf-sheaths flattened. Panicle somewhat
close and secund, some spikelets being nearly
sessile._
_P. compressa_, L.
_xx Stems and leaf-sheaths terete. Panicle spreading
widely._
_P. pratensis_, L.
ΔΔ _Without creeping stolons. Stems and panicle slender,
round. A shade-plant._
_P. nemoralis_, L.
The rarer species of _Poa_ are _P. bulbosa_ with the stems swollen
below; _P. alpina_, also slightly bulbous and often viviparous; _P.
laxa_ an allied Highland species; and _P. distans_ a maritime form
allied to _P. maritima_ (see p. 111).
** Spikelets with awns or with sharp terminal points (awn-points)
to the glumes or paleæ.
In some species and varieties of _Festuca_ awns are not evident
(see p. 116): the hard paleæ simply end in acute or acuminate
points, but these are sharp and in most cases much more so than in
any _Poa_. When not so evident, the student will probably think the
specimen is a _Poa_ and the flora must be consulted.
The difficulty is most likely to occur with varieties of _F. ovina_
and _F. elatior_: in the former the leaves are narrower, setaceous
and stiffer than in any _Poa_. The ribbing of the leaf, the ligule,
and other characters of the vegetative organs (see pp. 45 and 50)
will help in these doubtful cases.
† Awns terminal, or sub-terminal; often very short or nearly
obsolete and the paleæ merely drawn out at the tips to a
hard sharp awn-point.
⊙ _Awns long and sub-terminal, inserted between the teeth
of the cleft apex of the paleæ. Sheaths entire. Panicle
usually nodding._
+Bromus.+
With the exception of _Festuca Myurus_ and one or two other rare
Fescues with setaceous leaves, _Hordeum_ and _Brachypodium_ are
the only other genera with awns much resembling the Bromes. The
former has a totally different inflorescence, and in the latter the
spikelets are practically sessile (see p. 107).
≡ _Spikelets short and fat, and relatively heavy. Paleæ
broad and distinctly nerved. Awns fine, about as long
as the paleæ._
_B. arvensis_, L.
There are several varieties, of which _B. secalinus_ with a looser
panicle, and _B. mollis_ with a more compact panicle and very downy,
are the chief.
≡≡ _Spikelets lanceolate and with conspicuous awns.
Nerves on the paleæ obsolete._
_x Panicle conspicuously loose and drooping and awns
long, paleæ narrow and elongated._
_z Sheaths with long often reflexed hairs.
A shade-grass over three feet high._
_B. asper_, Mull.
_zz Sheaths downy. A weed of open lands and hedges,
two feet or less._
_B. sterilis_, L.
_B. giganteus_ is rarer than _B. asper_ and has smaller spikelets
and more slender awns. _B. maximus_ and _B. madritensis_ are rare.
⊙⊙ _Awns, if present, merely the points of the paleæ,
very short or obsolete. Sheaths split: ligule short._
+Festuca.+
≡ _Leaves flattened. Panicle somewhat close. Often tall
grasses._
_z Meadow-grass, with 5-6 to a dozen or more flowers
in the spikelet._
_F. elatior_, L.
_zz Shade-grass, with 4-5 flowers only in the
spikelet._
_F. sylvatica_, Vill.
≡≡ _Leaves subulate or setaceous, at least below. Mountain
pasture grass, usually small._
_F. ovina._
Concerning difficulties between _Poa_ and the awnless forms
of _Festuca_, see p. 114. _F. elatior_ and _F. sylvatica_ are
practically awnless, the awn-points being merely the acuminate tips
of the paleæ.
The long-awned species of _Festuca_ have compact stiff panicles and
narrow or setaceous leaves (see p. 111).
Regarding varieties of _F. ovina_, see p. 112.
†† Awns, twisted below and bent above, inserted into the
middle of the back of the bifid palea or below it.
⊙ _Awns long and conspicuously projecting from the spikelet,
which is gaping and contains 3-5 flowers. Leaves flat._
+Avena.+
≡ _Tall annual corn-weed, with large (18-20 mm.) heavy,
pendent, hairy spikelets on the long slender stalks
of the lax open panicle. Leaves glabrous._
_A. fatua_, L.
This is the so-called Wild Oat, and the type of this group.
≡≡ _Tufted perennials with spikelets more or less erect on
stiffer stalks, the panicle therefore less open._
_z Panicle nearly simple; spikelets silvery or
reddish, 12-15 mm. long._
_A. pratensis_, L.
_zz Panicle branched but not very open; spikelets
glistening yellow and only 5-6 mm. long._
_A. flavescens_, L.
There is no other genus closely resembling _Avena_. The superficial
likeness of some Bromes disappears at once on examination. The
spikelets of _Aira_ are much smaller, and the leaves quite
different (see below and p. 47).
⊙⊙ _Awns fine and hair-like and not conspicuously protruding
from the spikelets; the latter small, 2-5 mm. Flowers two
in each spikelet._
+Aira.+
≡ _Coarse and tall tufted grass with flattened, harsh, and
conspicuously ribbed leaves: the very short awns hardly
protruding._
_A. cæspitosa_, L.
No other grass can be confused with this if the very high ridges of
the leaves are observed (see p. 47).
≡≡ _Small grasses with setaceous or very narrow inrolled
leaves. Awns slightly protruding._
_x Palea distinctly bifid at the apex: awn nearly
twice its length. A very small grass about six
inches high: leaves subulate, fine and short._
_A. caryophyllea_, L.
_xx Paleæ almost imperceptibly bidentate: awn not much
longer than palea. About 12-18 inches high: leaves
inrolled._
_A. flexuosa_, L.
Other species of _Aira_, with more condensed inflorescences, are
dealt with on p. 112. _Agrostis_ is distinguished by the leaves and
one-flowered spikelets (see p. 104). _Poa_ and _Catabrosa_ have no
awns.