14 



FORAGE PLANTS AND THEIR CULTURE 



8. Characteristics of grasses. Botanically the grasses 

 form a sharply defined family characterized by having 

 jointed, usually hollow, stems, with cross partitions at the 

 nodes; two-ranked, parallel-veined leaves, the basal 

 portion or sheath inclosing the stem, and bearing where it 

 joins the blade a peculiar appendage, the ligule (Fig. 3) ; 

 flowers very small, mostly perfect, but sometimes uni- 

 sexual, consisting of 3 stamens, rarely 1, 2 or 6 ; one 

 pistil with two papillate or plumose stigmas ; and 2, 



FIG. 3 

 - Ligule 

 of a grass 

 leaf. 



FIG. 4. Spikelet 

 of orchard-grass. 



FIG. 5. A sin- 

 gle floret of orchard- 

 grass. 



rarely 3, small perianth segments, the lodicules at the 

 base of the ovary; flowers always in spikelets, with 2- 

 ranked bracts or scales, arranged on an axis, the rachilla. 

 The two lower bracts are called glumes, and each suc- 

 ceeding one is a lemma. Above and opposite the lemma 

 is the 2-nerved palea, which incloses the floret. The 

 florets are usually as numerous as the lemmas, but 

 the upper ones are often sterile. 



The fruit is a caryopsis or grain, with small lateral 

 embryo and relatively large starchy endosperm. For 

 the most part grass flowers are wind pollinated, but some 

 on which the stamens do not become exserted are self- 

 pollinated, as in the case of wheat. 



