1897] MICROSCOPICAL JOURNAL 273 



rounded by a denser, more or less differentiated, part of 

 the cell wall which is more yellow in color than the 

 remainder of the cell-wall. The second layer is of a yel- 

 low straw color and consists of very minute cells with 

 small cell cavities. 



The cell walls of the third layer are strongly thickened 

 brown and serve the same purpose as in the other species. 

 The endosperm consists of thick walled parenchyma 

 cells. In the first layer of cells the cell-walls are very 

 much larger and packed with protein grains. The other 

 layers of endosperm consist of small elongated thick 

 walled cells with a small cell-cavity. These attain their 

 greatest development between the caulicle and cotyledon. 

 In the embryo, the cells of the first row are isodiametric 

 filled with protein grains and oil. The outer cells are 

 eloDgated, larger, and also densely packed with the 

 same material. 



Capsella bursa-pastoris, Mornch. 



Pods two to three lines long, two to two and a half 

 lines wide above, some of the European specimens with 

 larger pods, many seeded (8-22), seeds light brown, one 

 half line long, nearly one fourth line in width, very minu- 

 tely roughened. Caulicle elongated forming a ridge 

 with slight depressions between it and the cotyledons. 

 The latter incumbent. On the addition of water the 

 outer seed coat becomes mucilaginous. 



Microscopic Structure. — The seed coats attain their 

 maximum development in the region of the caulicle. 

 Cuticle covers the epidermal cells, the latter tabular, 

 compressed but on the addition of water they elongate, 

 become mucilaginous and show stratification. 



The second and third layers are brown with thick cell- 

 walls. Fourth layer consists of endosperm, one layer of 

 isodiametric cells filled with protein grains, followed by 

 thick walled cells reaching thf^ir greatest development 



