m ] BARBER-FRUITS AND SEEDS OF CUCURBITACEAE 305 



cavities narrow, each sending out branches to the layers above and 

 below. The folds of the sinuous outer and inner walls are also 

 conspicuous in cross-section. In surface view the cells have sinuous 



walls and are irregularly arranged. 



4. Parenchxma.-The outer layer (p>) consists of small, thin- 

 walled, and sclerenchymatized cells without pits. It bears no resem- 

 blance to the corresponding layers of Cucurbita. Adjoining this layer 

 are two or three layers of true spongy parenchyma with large cells, 

 thin walls, and large intercellular spaces (p 2 ). From this tissue the 



(P 



The branching and anastomosing raphe ramifies through this 

 inner parenchyma. Although each branch contains but few bundle 

 elements, the branches are so numerous that they form a conspicuous 

 tissue, best seen in surface view (fig. 43) • 



pidermi 



Kte Pepo, consisting of a layer of small cells with thin walls, the cir- 

 cular contour of the radial walls being very noticeable. 



Perisperm (fig. 40, N) .-The structure of this tissue is the same 

 as that of the seeds already described, consisting of several layers 

 thin-walled parenchyma and an outer epidermis with cuticulanz < 

 outer and radial walls. The epidermal cells are elongated, in ma y 



Places transversely. . . , „,,_ 



Endosperm (fig. 4 o, £).-One layer of uniformly thickened celt . 



forms 



In one or two seed- 



examined there were indications of broken-down parenchyma 



The EMBRYO (fig 



• 



» iie embryo {Jig. 40, C) corresponds iu u«. b — ^^ 



the cotyledons having minute epidermal cells and mesop v 



w 'th oil ami nmt A ;« „™„,,w 



oil and protein granules. 



CYLINDRICA ROEM. 



The smooth, flattened seed (fig. 44) is I2 long ' ' ' 

 and 2 - 3 mm thick, of a dark-brown or black color. 

 Spermoderm (to. 4 ,-47) .-This is thick and consists 



tol| owing layers : 



*• Epidermis (ep) 

 thickno^ +u Q ^..4„_ 



(figs. 45-47) 



30-60 a* m 

 On each of 



(fS 



