6lO BOTANY OF CROP PLANTS 



cndocarp. Seeds are usually abundant, flat, and without 

 endosperm. 



Germination of Cucurbit Seeds. — The cotyledons are 

 epigean in all the common members of the Cucurbitaceae. 

 There are a few hypogean forms, such as Megarhiza calif ornica 

 and Sicyosperma gracilis. The first portion of the seedling to 

 appear above ground is the hypocotyl, which emerges as an 

 arch (Fig. 249) . At the base of the hypocotyledonary arch, 

 there is developed a peculiar outgrowth known as the "peg." 

 It is a natural part of the plant, and although it varies some- 

 what in size in different cucurbits, it has been shown that 

 gravity has no direct effect in increasing peg development 

 or in determining its lateral placement on the hypocotyl. 

 The peg serves to hold the seed coat while the hypocotyl 

 withdraws the cotyledons from the coat. It will be noticed 

 (Fig. 249) that one edge of the seed coat is caught against the 



peg- 



Key to Principal Geneka 



Corolla rotate or campanulate, five-parted to or almost to the base. 



Tendrils often two to three times branched, Cilrullus (watermelon, citron). 



Tendrils simple, Cucumis (muskmeion, cantaloupe, cucumber). 

 CoroU a campanulate, five-lobed to or little below middle Cucurbita (gourd 



pumpkin, squash). 



CTJCURBITA (Squash, Pumpkin, Gourd) 



Stems, Leaves, Flowers. — Members of this genus are 

 annual, prostrate bushy or trailing vines with rough stems 

 which have a tendency to root at the nodes. The tendency is 

 particularly marked in the long-running varieties of squashes 

 (Turban, Marblehead, Canada Crookneck, Field Pumpkin). 

 The tendrils are branched. The leaves are usually cordate 

 at the base, lobed (C. pepo), or not lobed (C. maxima). 

 The flowers are always solitary in the axils of the leaves, 

 yellow, and monoecious. In squashes with a bushy habit 



