INFLORESCENCE AND FLOWER 



15 



lower having either a staminate flower or only a palea. Very 

 often the spikelets are unisexual and the male and female spikelets 

 may be on the same plant as in Coix Lachryma-Jobi and Polyfoca 

 barbata, or they may be on different plants as in Spinifex squar- 

 rosus. 



The glumes of a spikelet arc really modified bracts and some 

 differentiate the flowering glumes from the empty ones, by giving 

 them different names. The first two empty glumes are called glumes 

 by all agrostologists. Some in Europe call the flowering glume 

 lower palea to distinguish it from the real palea which they call the 

 upper palea. Some American Authors have recently adopted for 

 the flowering glume the term lemma introduced by Piper. 



Considerable variation is met with in the case of the empty 

 glumes. Generally they are unequal, the first being smaller. Very 

 often the first glume becomes very small and it may be altogether 

 absent. In some species of Panicum the first glume is very small, 

 in Digitaria it is very minute and in Paspalum and Eriochloa it is 

 entirely suppressed. The flowering glumes are generally uniform 

 when there are many. In the spikelet having only four glumes 

 the fourth glume differs from the others mainly in texture. Instead 

 of being thin and herbaceous it becomes rigid and hard, smooth 

 or rugose externally as in Panicum. Flowering glumes instead of 

 being like empty glumes, become very thin, shorter and hyaline in 

 Andropogon. Sometimes the flowering glumes are awned. All of 

 them may be awned as in Chloris or only the fourth glume as in 

 Andropogon. 



The palea is fairly uniform in its structure in many grasses, but 

 it is also subject to variation. It becomes shorter in some and is 

 absent in others. Instead of having two nerves, it may have one 

 and rarely more than two. The palea can easily be distinguished 

 from the glume, because its insertion in the spikelet is different 

 from that of the glume. 



The lodicules are small organs and they are the vestiges of 

 the perianth. In most grasses there are only 

 two, but in Ochlandra and other bamboos we 

 meet with three lodicules. There are also 

 some species with many lodicules. In shape 

 they are mostly of some form referable to the 

 cuneate form. They are of somewhat 

 elongated form in Aristida and Chloris. The 

 function of the lodicules seems to be to separate 

 the glume and its palea so as to enable the 

 stamens to come out and hang freely at the 

 time of anthesis. So it is only at the time of 

 the opening of the flowers that the lodicules 

 are at their best. Then they are fairly large, 

 fleshy and thick and conspicuous. In the bud 

 stage they are usually small and after the 

 opening of the flower they shrivel up and are 

 inconspicuous. There are also species of 

 grasses in which the lodicules are not found. 



The stamens are three in number in the majority of grasses and 

 six are met with in Leersia, Hygrorhiza and Bamboos. Each 

 stamen consists of a very delicate long filament and an anther 



Fig. i 8. — Flower 

 Chloris. 



i. lodicules ; 

 2. stamens ; 3. ovary, 



