Pammel — Caryopsis and Endosperm of some Grasses. 203 



smooth coriaceous hard glumes consist of from four to six rows 

 of thick-walled sclerotic cells with a comparatively small cell- 

 cavity and radiating pore canals. The pericarp and testa are 

 but slightly developed because the protective features occur in 

 the glumes. The cells of the pericarp are elongated and thin- 

 walled. The walls of the testa are thicker, the layer being much 

 compressed. The cells of the aleurone layer are large and 

 consist of a single row. The starch cells are densely packed 

 with polygonal starch grains as in Zea. After dissolution of 

 the starch grains protein substances remain (PL XVII. 3). 



ANDROPOGONEAE. 



Various forms of Sorghum vulgare have been described and 

 figured by Harz.^ 



Sorghum vulgare, Pers. In chicken corn {Andropogon 

 Sorghum var. cernuum) the cells of the epidermis are thick- 

 walled, followed by a somewhat similar layer below. Under- 

 neath this occur elongated parenchyma cells with a narrow 

 cavity. The inner portion of the pericarp consists of thin- 

 walled cells which appear as circles somewhat widely sepa- 

 rated. The testa consists of a single row of large thin-walled 

 cells. The aleurone layer is usually of a single row of cells 

 much smaller than the starch cells. The latter contain nearly 

 spherical grains which are not closely packed. An abundance 

 of protein grains occurs in the starch layer. 



I was compelled to use this species, since I was unable to 

 get good seed in the herbaria consulted of any of our north- 

 ern species. Nor was I able to get good seed in the field 

 (PI. XIX. 4). 



PANICEAE. 



Of this tribe I have studied Panicum glahrum, Panicum 

 Crus-galli, Setaria italica and Cenchrus trihuloides. Harz ^ 

 has given us a good account of Panicum miliaceum and Pani- 

 cum sanguinalcy L. 



VI. c. 1249. /. 163, 164. 



2 1. c. 1255. /. 165, 166, XX-XXII.—P. sanguinale, 1. c. 1258. XXIII- 

 XXV. 



