PEPO 



657 



name " citrullol " was originally assigned has recently been shown 

 to consist of a phytosterol glucoside. The seeds contain about 15 

 per cent of a fixed oil. Power, Jour. Chem. Soc., 1910, p. 99. 



PEPO. Pumpkin Seed. The ripe seeds of Cucurbita Pepo 

 (Fam. Cucurbitacese), a procumbent herb, native of tropical America 



G E 



FIG. 290. Citrullus Colocynthis: A, seed: a, in longitudinal section, and b, 

 surface view; S, deep clefts or fissures; m, micropyle; g, hilum; w, radicle; 

 c, cotyledons. B, parenchyma cells of ripe fruit showing simple pores, 

 the walls are colored blue with chlor-zinc-iodide. C, longitudinal section of 

 wall of pericarp of ripe fruit showing e, epidermis; p, parenchyma; Sc, 

 sclerotic cells which gradually pass into a thick-walled parenchyma consisting 

 of small cells (p'); g, spiral vessels; P, isodiametric, porous parenchyma 

 cells, containing air and of which the fruit for the most part consists. D, 

 cross-section of seed-coat showing G, an outer layer which is more or less 

 easily separable from the rest of the seed and the walls of which are somewhat 

 mucilaginous; E, epidermis of palisade-like cells; Sc, sclerotic cells; PI, a 

 layer of tabular cells with undulate walls; T, a layer of small somewhat 

 branching cells, the walls of which are not strongly thickened and either porous 

 or reticulate; P, several layers of parenchyma and the collapsed epidermis; 

 Pe, perisperm; En, endosperm E, tangential section of tabular sclerotic 

 cells of seed-coat shown in PI in Fig. D. After Meyer. 



and possibly tropical Asia, and long cultivated in tropical and tem- 

 perate zones. 



Description. Anatropous, broadly elliptical, acute, acuminate 

 or truncate, flattened, about 20 mm. in length, 10 mm. in breadth, 

 about 2 mm. in thickness; externally white or light yellow, very 



