ARISTOLOCHIACEAE 73 



have a conspicuous, lurid calyx joined at the base to the 4- to 

 6-celled ovary. The fruit is, in our species, a many-seeded, 

 6-celled capsule. The flowers lack petals and contain 5 to many 

 stamens, which are more or less united with the style. 



Although chiefly South American, this family is widely known 

 in our climate by the Wild Ginger and the decorative vine com- 

 monly called Dutchman's Pipe. 



ARISTOLOCHIA (Tournefort) Linnaeus 

 Birthwort Pipe Vine 



The twining birthworts are extensive vines with alternate, 

 mostly petioled, entire leaves, which are ovate or cordate and 

 palmately nerved. The flowers are characteristic because of 

 the striking, bent and colored calyx, which is adnate to at least 

 the base of the ovary and extends as a narrow tube that usually 

 is inflated around the style and contracted at the throat, beyond 

 which the 3 lobes are either spreading or reflexed. 



Of the three twining species of this genus in Illinois, only the 

 following is woody. 



ARISTOLOCHIA TOMENTOSA Sims 

 Woolly Pipe Vine 



The Woolly Pipe Vine, fig. 13, is a twining vine with per- 

 sistently woolly or tomentose twigs, petioles and leaves, and 

 with strikingly curved, yellowish-green, large flowers that 

 somewhat resemble the Dutchman's Pipe. The alternate, 

 simple leaves are ovate to nearly orbicular, 3 to 6 inches long 

 or, generally, somewhat wider, rounded at the apex, and tend- 

 ing to be cordate at the base. They are quite veiny, with 3 

 primary veins that are conspicuous and plainly visible above, 

 and the margins are entire. The wooUy-tomentose petioles are 

 rather stout and 1 to 3 inches long. 



The flowers, which usually are few, occur singly on the stems 

 opposite the leaves, and the peduncles on which they are borne 

 generally are longer than the opposite petioles. The long calyx 

 tube is divided at its tip into 3 parts that spread or are recurved, 

 and are yellow above the purplish throat. The oblong, dry cap- 

 sule, 2 to 2Y2 inches long, is more or less tomentose and usually 

 has 6 prominent longitudinal ridges alternating with 6 less 



