594 ON SEEDLINGS 



are inserted at the base or suspended from the apex of the 

 cavity. To be basal and erect is however unusual. In 

 ovaries of three carpels and three cells, they are inserted on 

 the sides of the placentas nearest the peripheral walls. 



The fruit is in most cases baccate, and fleshy or cortical, 

 and botanically termed a pepo ; very often it is one-celled by 

 the destruction of the septa which become pulpy ; hence the 

 seeds are nearly always embedded in pulp. It is mostly in- 

 dehiscent, rarely opening by valves or by an operculum, and 

 many-seeded. In Elaterium and its allies the fruit separates 

 from its peduncle, leaving an opening through which the pulp 

 and seeds are ejected with some force by the elastic contrac- 

 tion of the walls. The seeds, like the ovules, vary in direction 

 and are very often flattened as in the Passiflorese. The testa 

 is membranous, cartilaginous or crustaceous, granular, tuber- 

 culate, or smooth, sometimes covered with a watery epidermis, 

 and toothed or lobed at the edges. The tegmen also varies 

 in thickness and other characters. Endosperm is wanting; 

 and the embryo therefore conforms to the cavity of the seed. 

 The cot3'ledons are foliaceous and flattened, or plano-convex 

 according to the thickness of the seed ; and the radicle is 

 comparatively short. 



Besides the anomalous or unusual forms mentioned above, 

 Sechium edule is remarkable for its large, obovoid, fleshy, one- 

 celled, one-seeded fruit. The seed is also large, subglobose, 

 with a woody testa, and conforms to the interior of the indehis- 

 cent fruit. The embryo is very large and germinates in the fruit 

 before the latter drops from the plant. The ovules and seeds 

 of Hodgsonia heteroclita are connate in pairs, of which one is 

 large and fertile, and the other small and empty. 



A type of an obovoid and rather thickened seed is furnished 

 by Bryonia dioica. It is surrounded by a slightly raised 

 margin and is somewhat compressed laterally with a pale, 

 crustaceous testa. The cotyledons are plano-convex, but 

 otherwise characteristic of the Order. The average size of the 

 seeds is 4*4 mm. long by 3'08 mm. wide and 2'2 mm. thick. 

 The seeds of B. laciniosa (fig. 389) are somewhat larger, being 

 5 mm. long by 3 mm. wide. They are surrounded at the edges 

 by a narrow ridge, and have a large mass of cortex projecting 



