312 THE AMERICAN MONTHLY [Oct. 



On the Seeds and Testa of Some Cruciferac. 



By L. H. PAMMEL. 

 ames, iowa. 



WITH FRONTISl-IECE. 

 Conthiued front page 2J4, 



Camelina sativa, Crantz. 



Pod obovoid, four to six lines long, smooth, reticula- 

 ted, margined from beak down along placental side with 

 smaller ribs between them. Seeds light brown, one line 

 long, minutely pitted, caulicle prominent, running 

 lengthwise with a prominent groove between it and the 

 cotyledons. Cotyledons incumbent.* 



Seed coats consisting of four layers. The outer epi- 

 dermal cells not much longer than wide, on the addition 

 of water become mucilaginous and well stratified. On the 

 addition of chloral hydrate stratification more evident. 

 The cell-walls ditferentiated into several different sub- 

 stances. The second layer not always developed. Cells 

 ot third layer with thick walls and brown pigment, fol- 

 lowed by a narrow layer of thick walled brown cells. 

 The first row of cells of endosperm, rather thick walled, 

 filled with protein grains, the other layers of unequal 

 development, cells elongated, thickwalled ; followed by 

 cells of embryo; these contain protein grains and fat. 

 EXPLANATION OF THE FIOUUES. 



I. July text, page 209, (Reprint, page 7). Brassica nigra: a, rancilag- 

 inous cell before the addition of water; b, after addition of water; 3, brown 

 thick-walled cells; 4, parenchyma cells; 5, aleuroue layer; 5-6, endosperm; 

 7 cells of embryo. B. siuapistrum: c, mucilage cells expanded; 4, endos- 

 perm in figure to the left, embryo in ligure to the right. 



II. September frouti-ipiece (Reprint, page 12). Sisymbrium altissimum, 

 S. oiruinale and Capsella bursa-pastoris: The upper row of cells consists of 

 mucilage cells; the lower row contains embryos; about midway between 

 may be seen the endosperm. 



III. September text (Reprint, page 13). Lepidium virginicum. 1, mucil- 

 age cells; 3, 4, endosperm; 5, cells of embryo; b, mucilage cells when 

 moistened. 



IV. October frontispiece (Reprint, page 15). Brassica alba: Upper row, 

 mucilage cells; third and fourth rows, endosperm. Camelina sativa: upper 



*Har7,. 1. c. p. 924. Fig. 71. 



