10 TEXTBOOK OF BOTANY 



and, as we say, ripe. The spines that were noticed on the 

 surface of the ovary remain hard and sharp while the fruit is 

 growing, but many or all of them (in most varieties of cucum- 

 ber) dry and fall or are rubbed off before it is ripe. A cross 

 section of the ripe fruit shows about the same structure as one 

 through the ovary, except that all the parts are much larger. 

 The ovary wall has become thicker and hard ; it is now the 

 fruit coat or rind. The tissues that made up the inside of the 

 ovary have become soft and juicy, and the ovules have grown 

 into seeds, whose structure we have studied. The fruit of 

 the cucumber, unlike many other fruits, has no means of 

 opening or of scattering its seeds. Therefore, unless the 

 fruit is broken open in some way, the seeds remain inside, 

 protected by the fruit coat until the latter decays ; then they 

 fall upon the ground and are in a position to germinate. 



14. Length of Life. The whole history that we have' 

 followed is passed through in one season. The cucumber is 

 an annual; that is, no part of the plant lives through the 

 winter, but new plants must be raised from seed each year. 



15. Relatives of the Cucumber. The cucumber is a representative 

 of the genus Cucumis. The botanical name of the species is Cucumis 

 sativus. Another species of the same genus is Cucumis melo, the musk- 

 melon. These plants belong to the gourd family, which includes about 

 700 species, the greater part of them natives of the tropics. The pumg- 

 kin and the summer squash (both forms of Cucurbita pepo) are mem- 

 bers of the same family ; so are the Hubbard squash (Cucurbita maxima), 

 the winter crookneck squash (Cucurbita moschata}, the watermelon 

 (Citrullus vulgaris), and gourds of various forms (Lagenaria vulgaris). 



16. Historical Note. The cucumber is thought to have been 

 originally a native of East India. It has been cultivated from the 

 earliest times, and is said to have been introduced into China about 

 200 B. c. Many different varieties have been produced. The pumpkin 

 is probably a native either of Central or of South America. Pumpkins 

 were under cultivation by North American Indians when the continent 

 was discovered by white men ; but the pumpkins then grown seem to 

 have been more like the gourd pumpkins than like the field pumpkins 

 of the present day. The origin of the different squashes is uncertain. 



