THE AMERICAN 



^V . MONTHLY 



MICROSCOPICAL JOURNAL. 



Vol. XVIII. SEPTEMBER, 1897. No. 9. 



On the Seeds and Testa of Some Cruciferae. 



By L. H. PAMMEL, 



ames, iowa. 



[Contributions, No. G, Botanical Department, Iowa Agricultural College.] 



WITH FRONTISHECE. 



Continued from page 210. 



Sisymbrium officinale, Scop. 



Pod a half inch long or more, awl-shaped, somewhat 

 four sided, borne on short erect pedicels, twelve seeded, 

 seeds liglit brown, oblong, or in some cases, triangular, 

 one half to three fourths of a line long, Caulicle extend- 

 ing lengthwise with a depression between it and the 

 cotyledons. Cotyledons incumbent. 



Seed coats quite uniformly developed. Cuticle cover- 

 ing the epidermal cells, the latter tabular, much com- 

 pressed. On the addition of water the cell walls become 

 mucilaginous with evident stratification. The second 

 layer of cells brown and thin walled, much compressed. 

 On addition of chloral hydrate they expand. Third 

 layer much darker than the second, thick walled, fol- 

 lowed by endosperm, cells elongated filled with protein 

 grains, followed by elongated thick walled cells with a 

 small cavity. These reach their highest development 

 between cotyledons and caulicle. First row of cells of 

 the embryo nearly isodiametric, filled with protein grains 

 and oil. 



