1 84 MONOCOTYLEDONS 



whereas the upper pale is on the almost imperceptible 

 flower-stalk, and is often two-ribbed In many Grasses, on 

 each flower-stalk, higher up than the upper pale, are 

 inserted two minute scales — the lodicules (figs. 233, 236 /). 

 Some botanists regard these latter as representing a simple 

 perianth J others are of opinion that they represent a small 

 divided bract, in which case they are not a portion of the 

 flower proper. The Flower consists of three (rarely two) 

 stamens inserted below the ovary, and possessing dangling 

 anthers ; together with a one-chambered ovary containing one 

 parietal ovule, and surmounted by two brush-like or feathery 

 stigmas. It is usually supposed that the gynaecium represents 

 one carpel, the style of which has branched. If this view be 

 correct, it must be described as being apocarpous. 



Different types of Grasses. — The spikelets may be arranged 

 in panicles or in spikes. In each spikelet there may be one or 

 more flowers. The lodicules may be present or absent. The 

 accompanying table (see opposite) illustrates the general details 

 in some common types of Grasses. (In all these the gynascium 

 is the same throughout as regards its general constitution.) 



Pollination of Grasses. — In some grasses (e.g. Poa and 

 others) the upper and lower pales enveloping a flower 

 separate considerably ; the anthers emerge and dehisce 

 quickly, and the stigmas separate. It is the lodicules 

 which cause the opening; they swell and force back the 

 lower paleae. After a time the lodicules shrivel up, and 

 consequently the paleas close. In other grasses the palese 

 scarcely open, and the stigmas are brush-like (not feathery). 

 As the lodicules are not called upon to force the palese 

 apart, they are absent (e.g. Timothy-grass) or very minute 

 (e.g. Foxtail-grass). The grasses are cross-pollinated by the 

 agency of the wind; the long filaments, with their dangling 

 anthers, are easily shaken by even light lareezes, and the large 

 brush-like or feathery stigmas display a large surface to receive 

 the wafted pollen. Many grasses are regularly self-pollinated 

 (e.g. Wheat, Barley, Oats). 



Fruit. — After fertilisation the one-ovuled ovary gives place 

 to a dry one-seeded indehiscent fruit very like an achene; 

 but the seed is so closely adherent to the pericarp (original 

 wall of the ovary), and the testa so thin, that it is impossible 

 to distinguish the testa and pericarp without the aid of a 



