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Those branches which form the tufts are produced from a number of intravaginal buds lying close 
together; these grow vertically upwards, directly into the air, and become leafy branches which later 
on produce culms and flowers (fig. A). 
The culm is smooth (hence the term »smooth-stalked«), erect, 1—3 ft. high, cylindrical or some- 
what compressed and two-edged. The young leaf-sheaths are smooth, glabrous, laterally compressed, 
entire, and deeply folded opposite the midrib (fig. 17b) except at the base (fig. 17a). Hackel describes 
a similar fold in Festuca amethystina and Festuca scaberrima. Folding begins about one-fourth above 
the base, reaches a maximum three-fourths up (fig. 17b), then decreases, and at the summit is again 
very slight (fig. 17c). By the growth of the parts contained within the sheath, the fold is soon obli- 
terated and ultimately ruptured. Old sheaths and those on the culms are split in this way. Déll, 
Ascherson. and others describe the sheath as split: this is only true of the old sheaths; young sheaths 
are always entire. The leaf-blade is folded in the bud: its other characters depend upon the variety 
(see below). Each blade contains seven strong and well-developed fibrovascular bundles (veins) extending 
from the upper to the lower epidermis, and a variable number of weaker bundles between these (fig. 18). 
The epidermis of the upper surface has six bands of specialised cells forming three symmetrical pairs 
of »Bulliform cells« (Duval Jaure) or »Gelenkzellen« (Tschirch), shewn in fig, 18. The furrows corres- 
ponding to the stronger veins are very slight and the blade is accordingly almost ribless (fig. 18), The 
ligule is short and obtuse (fig. 19). The inflorescence is a pyramidal panicle, closed before, but sprea- 
ding during and after flowering (fig. A); the colour is bluish green, frequently variegated with brownish 
purple. Each spikelet contains 3, 4 (fig. 1) or 5 flowers. The glumes (fig. 1) are almost equal, acute, 
and ciliated towards the apex of the keel (fig. 4). The Jower pales have long, silky, curly hairs which 
interlace with one another and with those of adjoining pales forming the Web (»Lana conjunctivas) 
these hairs are longest at the base, but they also extend three-fourths up the keel and the marginal 
ribs; on the latter they are shortest (fig. 3). The presence of the web is easily recognised when the 
spikelet is broken; the detached pales do not fall to the ground but remain suspended by it (fig. 2). 
By this character, Poa pratensis and trivialis are readily distinguished from Poa annua: — in the 
latter, the hairs are present but do not form a web; accordingly, the pales when detached fall to the 
ground. The upper pale is very slightly shorter than the lower, and has a pair of ciliated keels only 
seen where the lower pale has been removed, as in fig. 12. The flower (fig, 5) is composed of two lodi- 
cules, broad at the base, deeply bifid and eroded at the summit; three stamens; and a pistil formed of an 
ovary longer than the lodicules, bearing two feathery stigmas (fig. 5). 
Flowering goes on as in Perennial rye-grass. When ripe, the spikelet breaks up into false frwits 
(seeds); each is composed of a caryopsis contained in a pair of pales, and a stalk lying in front of the 
upper pale (fig. 10). The webs bind the false fruits together; those from one spikelet interlacing with 
those from another to form clumps (fig. 6), If a ripe panicle of Poa pratensis is touched by a passing 
animal the webs attach the seeds to its body; the meaning of the hairs is thus plain: — they facilitate 
the distribution of the seed by passing animals. The caryopsis lies free within the pales which are accord- 
ingly easily detached. The lower pale becomes broad towards the apex, and the ribs are not prominent 
on the surface (fig. 41); the margins overlap and conceal the keels of the upper pale (fig. 10). The 
upper pale is very slightly concave and has no groove (fig. 10). The stalk of that false fruit which 
occupied the apex of the spikelet is half as long as the fruit itself, and is terminated by a small globular 
head formed of barren pales (fig. 9); the other false fruits have a truncate slalk (fig. 10), The caryopsis, 
like the upper pale, is very slightly concave on the ventral surface ; the back is rounded (fig. 16); at 
the base, on the ventral surface is the rounded hilum (fig. 14), on the dorsal, the embryo (fig. 13); both 
ends are pointed, and the apex is crowned by the withered styles (not by a tuft of hairs), 
Length of false fruit 2—3 mm. 
,, caryopsis 1—1.6_,, 
. ,, stalk ‘/o>—'*/2 of false fruit 
Thickness of stalk 0.08 mm. 
39 
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