288 THE VEGETABLE WORLD. 
vening between the knots are hollow tubes. From these knots 
spring the leaves. Their petioles form a split sheath on one side, 
which embraces the stem for some distance before spreading out 
into a very long slender leaf, traversed by parallel and simple 
veins, converging towards the summit. At the point where the 
leaf separates from the sheath, we find a small, whitish, membranous 
band, which appears to be a con- 
tinuation of the inner lining of 
the petiole beyond the origin of ia 
the lamina of the leaf. In the 4 
accompanying engraving. (Fig. 
350), of an annual grass, Poa 
annua, 8 is the sheathing petiole, called ligula 
(shoe-latchet), 1 a the lamina, ” the tumid node, * 
at which the leaf originates. 
The infloresence of the Oat is a loose, but ample 
panicle, displaying branches on all sides. If we 
examine more closely these little fructifying pen- 
dants, which from the delicacy of their peduncles { '4) 
oscillate freely to the breeze which skims over the |\ 
surface of the field of oats, two pointed scales will | /| 
be observed on the outside, almost equal in size, | | / | 
but one of which is inserted a little lower than | | f i 
the other; this constitutes the envelope, protector, | 4 
| 
or glume of three distichous flowers, forming 
a little ear or spikelet (Fig. 352). The lower wa. 
flower is fully developed, the second is smaller, and the ot 
rudimentary and sterile. If we examine the lower flower, - 
is composed essentially of three stamens and a pistil. The — 
ments of the stamens are delicate, and the anthers, w! ich nee < 
the shape of an X, are loosely attached by the back. The er 
is composed of a shaggy, hairy ovarum, which surmounts ae 
feathered styles. There is only one cell in the interior, a 
ing an unique and anatropal ovule. These essential organs 
tected by a system of two scales, the external or lowest “ at, 
bears upon its back a caducous and rigid filament, slightly bel ae 
while the internal one, which is much smaller, is supplied ‘gn 
two lateral veins. This system constitutes the glume. ot a 
