478 



[JUNE 



BOTANICAL GAZETTE 



Membrane of grapefruit {Citrus grandis) 



• La> u r { (fi ?,' 5) iS a muciIa S inous mass of cell wall material 

 giving both cellulose and pectin reactions. The slimy character 

 of soaked seeds of this species is due to this layer. At o is a thick 



/ 



Fig. 4 . 



Cross-section of seed coat of Amygdalus communis, X450 



suberized layer impregnated with tannin 



materials 



and other coloring 



membranes 

 and w. 



I he inner wall of this layer is especially well suberized. 

 esistant to chromic acid than any layer in any other 



*~«„^. j.u C tmC K endosperm layer is marked at d 

 In some places this layer is 2 cells and in other places only 

 -de the walls are very thick and are composed of cellulose 

 impregnated with pectin. They break apart on treatment with 





I 



