MICROSCOPIC STRUCTURE OP WEED SEEDS 



659 



Measurements, seed coats, 122/*; outer integument, 27/*; outer 

 layer of same, 22/*; inner layer of same, 5/*; palisade layer, 70/'; 

 subpalisade, 25/*. (P. H. Rolfs.) 





Fio. 426. Microscopic structure of the seeds of some Malvaceous weeds. 

 I. Slioo-fly (SiftiscKS trionum). II. Indian Mallow or Butterprint (AtvXMon 



theophrasti) . III. Mallow (.Malva sylvestris). IV. Slda (.Sida spinoaa). 



V. Cheeses or common Mallow (.Malva rotundifolia) . 

 ep=epidermal cells. m=malpighian cells. ll=light line. pi=pigment layer. p= 



parenchyma cells. pal=palisade or malpighian cells. n=nucellus. en=eii- 



dosperm. h=trichome. t=plant hair or trlchome surface view 

 (Drawings by P. H. Rolfs.) 



Cheeses or Mallow {Maiva rotundifolia L.). 



The roughened, somewhat velvety, dark grayish seeds consist 

 of an outer row of rather large, rather thick-walled cells, walls 

 colorless. This layer is followed by the very long Malpighian 

 cells, which are longer than the cells of the rest of the testa, light 

 line near the upper part of the cell, lower portion of cell slightly 

 yellowish. Cavity spindle-shaped near the middle. The dark 



