CH. I] 



The Morphology of Grasses 



17 



Holcus, Alopecurus, Panicum, etc. 1 In the genus Hordeum the 

 so-called "seeds" often consist of the three united mature 

 spikelets. In a few instances the "seed" consists of the grain 



Kg. 21. I. Central cross-section of a grain of the cultivated Oat, Avena sativa, L. 

 II. A small piece of the peripheral portion more highly magnified. 1 and 2, 

 the pericarp; 3, testa; 4, remains of the nucellus; 5 — 7, amylaceous tissue; 

 5, gluten cells ; 6 and 7, cells of albumen containing compound starch-grains — 

 at 7 they are richer in albumen and poor in starch; 8, fibro-vascular bundle 

 of the seed-coat. Haiz. 



shed free from its paleae, as in the common varieties of Wheat, 

 and sometimes Timothy-grass. 



1 For other types see Anthoxanthum and Arrhenatherum. 



2 



