1897] MICROSCOPICAL JOURNAL. 271 



The second layer is colored brown, the cell-walls are 

 considerably thickened laterally and project upwardly in 

 the shape of cones. A section made through the ends of 

 these seeds shows that the second layer is considerably 

 more developed and there are evidences here of an indis- 

 tinct layer between the first and second. The layer fol- 

 lowing this consists of thin walled parenchyma cells, in 

 some cases considerably elongated but in others short. 



The third layer is followed by the endosperm which 

 consists of a layer of rather thick-walled parenchyma 

 cells. These carry granular protein grains. This is fol- 

 lowed by one or more layers of elongated cells, in which 

 the cell cavity is very much reduced. These cells reach 

 their highest development between the folds of the cau- 

 licle and cotyledon. 



The Embryo: — The first layer of cells of the embryo 

 are smaller, quite uniform in size and filled with protein 

 grains and oil. 



Lepidium apetalum, Willd. 



Pod a line and a quarter to a line and a half long smaller 

 than Large Pepper grass, slightly notched at the apex, 

 minutely pubescent. 



Seeds pendulous, light brown, very slightly roughened 

 and very narrow wing margined. Smaller than in L. 

 virginicam, three quarters to nearly a line long. Cauli- 

 cle extends lengthwise, with a prominent ridge as in L. 

 virginicum, with a sharp groove between caulicle and 

 cotyledons, the latter incumbent and flattened, a charac- 

 ter which easily separates the species from the Large 

 Pepper Grass. 



The cuticle forms a continuous layer over the epider- 

 mal cells, the latter are larger than in L. virginicum. On 

 the addition of water the cell wall rapidly elongates, 

 emitting a copious mucilage, the cell-cavity is very much 

 reduced but longer than in L. virginicum. It is sur- 



