CUCURBITA 



589 



carp. They are isodiametric with thick walls; and, in the variety 

 verrucosa, the region is characterized by many layers of polygonal 

 stone cells. The middle mesocarp (4) is made up of cells which 

 are progressively larger and more loosely arranged than those of 

 the outer mesocarp. The outermost cells contain numerous starch 

 grains, the number decreasing toward the inner limits of this zone. 



A B 



Fig. 308. A, transection of portion of seed of Cucurbita Pepo; B, surface view of portion 

 of epicarp of immature fruit sfiowing epidermal hairs : al, aieurone grains ; cot, cotyledon ; 

 end, endosperm ; ep, epidermis ; gl hr, glandular capitate hair ; hr, conical hair ; hy, pitted 

 subepidermal layer; w\ pitted parenchyma ; w^, reticulate spongy parenchyma; />', paren- 

 chyma; />^ spongy parenchyma; /'^ inner epidermis of seed coat; psm, perisperm; s c, seed 

 coat; jc/, sclerenchyma ; j- ^, starch grain ; j-fo, stoma. (Redrawn after Barber.) 



The inner mesocarp (5) consists of large parenchymatous cells 

 without much cellular contents. Throughout the mesocarp 

 there are vascular bundles and isolated sieve tubes, as well as 

 latex tubes which anastomose with each other. The central 

 portion of the fruit is occupied by tough fibers surrounded by 

 disintegrated parenchymatous cells. The innermost zone or 

 endocarp (6) is made up of very small, thin-walled cells that are 

 tangentially elongated and form a thin membranous tissue which 



