The ovule is fertilised in the usual way, by a pollen tube growing down the style from a grain on the stigma. As a result of fertilisation the ovary becomes a fruit containing one seed which fills it. In many cases (e.g. barley and oats) the pales still remain in position and adhere to the fruit. When the awn is present it may play an important part in distributing the “seeds” by clinging to the hides of animals, etc. [Pg 132] Sometimes the awn is of use in fixing the grain in position on the ground until the seed has germinated. The structure of a grass seed has already (p. 19) been studied in the wheat and maize. The developing embryo (p. 21) lives upon a store of food called the endosperm (Fig. 16) until its roots and leaves are sufficiently advanced to make food for themselves. 29. SOME COMMON GRASSES. 1. The fescues.—Gather plants of meadow fescue, and examine the habit of growth (in tufts), the broad leaves, and the nodding panicles and the flowers. Also examine the “seeds.” Compare sheep’s fescue (Fig. 102), and notice the very fine leaves. The outer pales are awned. 2. The meadow grasses.—Examine the various species of meadow grass (Fig. 103). They can be distinguished from each other by the characters of the ligules. Notice the tree-like habit of the panicles and compare them with the fescues. The meadow grasses never bear awns. Notice the woolly “webs” at the bases of the “seeds.” 3. The foxtails.—In meadow foxtail (Fig. 104) notice the prostrate stolons and large succulent leaves. Does the grass grow in tufts? Why not? What is the earliest date on which you have seen it in flower? Double the ear on itself to see the short stalks of the spikelets. How many flowers are there in each spikelet? Notice the silky awns of the flowers. Compare the slender foxtail (Fig. 105), which is a troublesome weed. 4. Timothy.—Compare the leaves and flowers of timothy or “meadow catstail” (Fig. 106) with the meadow foxtail. The ear is green and rough, and the flowers are awnless. What is the date of flowering? 5. Yorkshire fog.—Notice the woolly covering of this weed (Fig. 107). This covering and its bitter flavour make it distasteful to cattle. Observe the “kneed” awn of the flower. Dig up and shake off the earth from a sod to see the stolons. [Pg 133] 6. Wild oat (Fig. 108). Examine the large spikelets and make out the long twisted awn of the flower. Compare this weed with the cultivated oat (Fig. 99) and with the yellow oat grass. 7. The perennial rye grass.—Notice that the ear is flattened, and that the spikelets are without stalks and have only one glume. The leaf is glossy and has a prominent midrib and a flattened sheath. Fig. 102.—Sheep’s Fescue. (× ⅙.) Fig. 103.—Smooth-stalked Meadow Grass. (× ⅙.)