38 THE ORDER AND ITS TRIBES. 



increased to many ; carpel single ; ovary one-celled, usually with 

 two, rarely with one or three, lateral stigmas ; ovule solitary, 

 with micropyle pointing downwards : fruit usually a caryopsis ; 

 embryo outside the endosperm in front at its base, small 

 and straight with a shield-like development of the cotyledon 

 towards the endosperm ; radicle and plumule well-developed. 

 Herbs, rarely shrubs or trees, mostly perennial, with jointed 

 stems ; leaves distichous, consisting of a sheath and blade with, 

 generally, a ligule at the junction. 



Hackel, whose classification is the best we have, divides the 

 grasses into thirteen tribes, to which the following will be found 

 a useful key. It is not quite the same as his, but good enough 

 for practical purposes, and saves us from the repetition of details 

 we shall have to deal with a page or so further on. 



Stem woody. 



Leaf often joined to sheath by a petiole. BAMBUSJE. 

 Stem not woody. 



Leaf not joined to sheath by a petiole. 

 Spikelets with one or two florets (lower floret when present 

 imperfect) falling entire at maturity. Rachilla not 

 produced beyond the florets. Internodes between 

 glumes or florets, when present, not distinct. 

 Florets not laterally compressed. 



Paleae hyaline (that is glassy) ; lower glume the larger. 

 Spikelets male or female. MAY DEM. 

 Spikelets perfect or male and perfect. 



ANDROPOGONEJE. 

 Paleae not hyaline. 

 Paleae membranous. 



Lower glume the larger. ZOYSIEM. 

 Lower glume the smaller. TRISTEGINEJE. 

 Paleae not membranous. PANICEJE. 

 Florets laterally compressed. ORYZEM. 

 vSpikelets with one or many florets. Those with one floret 

 frequently with rachilla produced beyond it; rachilla 

 generally jointed above glumes so that these remain 



