THE BIETHWORT FAMILY. 



265 



and are only grown as curiosities ; as such they are highly 

 prized in this country. 



The Birthwort Family. 



(Aeistolochiace^.) 



Small trees or shrubs, generally climbing ; or gemmse- 

 corms. Leaves alternate, round, elliptical, cordate, or lobed 

 at their base, some with leafy scale-like stipules. Flowers 

 axillary, solitary, bisexual, on long stalks or on very short 

 stalks, and rising direct from the stem. Calyx (corolla-like) 

 tubular, straight or bent, with a regular limb, or very 

 irregular, consisting of a large flaccid lip sometimes with a 

 spur. Stamens (anthers) 6 — 12 or 24, sessile, seated at the 

 base of the tube, adhering to the pistil, which is short, rayed, 

 or circular, and button-like. Fruit a succulent or dry 

 membranous capsule containing thin flat seeds. 



Nearly 150 species constitute this family, the arborescent 

 and climbing ones being chiefly natives of the tropics. 

 They abound in America, where with Passiflora and Big- 

 nonia they form an interminable interlacing of the forests, 

 causing them to appear as if the whole were tied together with 

 ropes. A few herbaceous species are found in distant locali- 

 ties over the temperate northern hemisphere. On account 

 of the peculiarities of structure both in flowers and wood, 

 the relationship of Aristolochia is not well defined. There 

 is only one floral appendage, which, although extraordi- 

 narily developed, and assuming the appearance of a corolla, 

 is nevertheless described by botanists as a perianth (calyx). 

 It is probable, however, that it is a true corolla, and that the 

 calyx is suppressed, its place being shown by a small disc 

 round the base. The structure of the stems of the woody 

 species is also peculiar in having no concentric circles, but 

 separating lengthwise in wedge-shaped plates. 



Considerable medicinal qualities are ascribed to some of the 

 species, which are bitter, tonic, and stimulating ; but its chief 

 fame is its supposed efficacy in the cure of snake-bites. 



