REPRODUCTION AND DISPERSAL 



871 



morphic corollas, which not only are more or less closed, but commonly 

 are swung laterally, as in the labiates (fig. 11 74) and in the orchids. 



The protection of flowers by closing. — Closure during anthesis usually 

 involves a single flower, but sometimes it involves an entire inflorescence, 



Fig. 1 192. — Yucca flowers: A, an inflorescence of Yucca patens with numerous 

 pendulous flowers ; B, flowers of Yucca Treculeana ; note the perianth, the stamens with 

 recurved anthers, and the stigmas. — From Trelease. 



as in the heads of the milky-juiced composites (figs. 1193, 1194). Most 

 such flowers or inflorescences open in sunshine and close at night and in 

 cloudy weather, though in a few cases this order is reversed, the flowers 

 opening at night and in cloudy weather and closing in the sunshine. 

 Some flowers open for two successive days (as in the poppy), others 

 for three to five days (as in Eschscholtzia); the flowers of Crocus and 

 Hepatica may open daily for more than a week. Usually npcturnal 



