208 Trans. Acad. Sci. of St. Louis. 



and describes Deschampsia, Aira 1 and Arrhenatherum . 2 

 In some of these genera the nucellus is very evident. In 

 all, the starch grains are compound. The genus Avena has 

 been described by a large number of writers, Tschirch und 

 Oesterle, 3 Moeller, 4 Hanausek, 5 Klencke, 6 and Barnes. 7 



In Arrhenatherum avenaceum, Beau v. the pericarp consists 

 of elongated thin-walled cells with a large cell cavity. This is 

 followed by a compressed layer of several rows of cells some- 

 what difficult to make out in most sections. The testa con- 

 sists of several rows of thicker walled cells followed by the 

 remnants of the nucellus. The outer portions of the endo- 

 sperm consist of the aleurone layer of two rows of cells 

 densely filled with protein grains. In the outer portions of 

 the starch layer, the compound starch grains are less abun- 

 dant than in the interior. The compound grains are large, 

 with the component parts decidedly angular (PI. XVII. 2). 



Avena saiiva, L. In common oats the caryopsis is slightly 

 hairy. The large epidermal cells are thick-walled, slightly 

 irregular on the surface, followed by several rows of thick- 

 walled cells in a general way much like the epidermal cells. 

 The testa consists of a much compressed layer mostly of two 

 rows of thick-walled cells ; remnants of the nucellus evident. 

 The aleurone layer of the endosperm consists of one or two 

 rows of cells ; the outer portion of the starch cells contains 

 less starch than the inner. The starch consists of large com- 

 pound grains, the component parts five- to six-sided (PI. XIX. 

 6, A. B.). 



CHLORIDEAE. 



Of the Chlorideae the writer has studied only Bouteloua 

 hirsute/,, Lag. The pericarp and testa are but slightly devel- 

 oped. The epidermal cells of the caryopsis are thick-walled, 

 elongated. Two or three rows of compressed thick-walled 

 cells follow the epidermis. The testa consists of two rows 



1 Aira, 1312. 2 Arrhenatherum, 1308. 



3 Anatomischer Atlas. 9. pi. 44. 



4 Nahrungs- und Genussmittel. 105, 160. 



s Die Nahrungs- und Genussmittel aus dem Pflanzenreiche. 36. 



6 Lexikon der Verfalscbungen. 240. 7 Plant Life. 301. /. 346. 



