THE BIKTHWOET FAMILY. 349 



CVIL— THE BIRTHWORT FAMILY. AristolocMdcece. 



A little family of singular plants, difficult to associate with any 

 other. They are exogenous in the main points of their structure, but 

 like the Berbery (p. 150), resemble Endogens in the trimerous division 

 of their flowers, and in some respects in habit. Some are herbaceous, 

 others shrubby, while a good many have twining stems. Leaves 

 alternate, simple, and stalked ; flowers axillary, solitary, brown, yel- 

 lowish, or of some dull colour, and consisting of a tubular calyx only ; 

 stamens six to twelve ; ovary below the flower, usually six-celled. 



Equinoctial South America is the chief station of these plants, very 

 few species occurring in the north, and two only in Great Britain. 

 These are the common birthwort, or Aristoldchia Clematitis, (Curtis, iv. 

 639.) and the asarabacca, or Asarum Europceum, (E. B. xvi. 1083.) 

 both of old repute in medicine, and cultivated in gardens by the 

 curious. Birthwort has erect, zigzag, unbranched leafy stems, about 

 two feet high ; rather large, broadly heart-shaped leaves (Fig. 182), 



Fig. 182. Fig. 183. 



and long, slender, curved, horn-like, pale yellow flowers, several in 

 the axil of each leaf. Asarabacca has very short stems ; the leaves 

 nearly radical, kidney-shaped (Fig. 183), shining, on long stalks, 

 two on each stem, and a good deal tufted, with a solitary, greenish- 

 brown, bell-shaped flower, about half an inch long, accompanying 

 each pair of leaves, and upon so short a peduncle as to be entirely 

 concealed. The leaves vary from an inch in breadth to as much as 

 three inches. 



Several species of Aristoldchia are cultivated in green-houses, but 

 none are common plants. 



