478 STRUCTURE AND LIFE HISTORIES 



which bears a tuft of long silky hairs, whence one of the 

 common names, ''silk weed." These hairs facilitate the 

 distribution of the seeds by the wind (Fig. 362). 



Fig. 362. — A milkweed {Asclepias syriaca), with tufted seeds scattering 

 from the dehiscing pods. (Photo by Elsie M. Kittredge.) 



420. Convolvulus Family (Convolvulaceae). — The fea- 

 tures of this family are well illustrated by the genus 

 from which it gets its name, Convolvulus, or bind-weed. 

 The five-lobed corolla is bell-shaped, all the parts of the 

 flower are in fives, and the pistil two-celled. Most genera 

 of the family are trailing or (as the name indicates) 

 twining vines (Fig. 363). 



