A RIS TOL CHI A CEA E. 347 



Family I. ARISTOLOCHIACEAE Blume.* 



Birthwort Family. 



Acaulescent plants, or with erect or twining stems. Leaves alternate, 

 often basal, exstipulate. Flowers regular or irregular, sometimes clus- 

 tered. Calyx-limb 3-6-lobed or irregular. Stamens 6-many, adnate to 

 the pistil ; anthers 2-celled, their sacs longitudinally dehiscent. Ovules 

 numerous in each cavity, anatropous, horizontal or pendulous. Fruit a 

 many-seeded 6-celled capsule. Seeds angled or compressed, with a crus- 

 taceous testa and usually with a fleshy or dilated raphe; endosperm 

 fleshy, copious ; embryo minute. Six genera and about 200 species of 

 wide distribution in tropical and temperate regions. 



Acaulescent herbs ; perianth regular, persistent ; filaments distinct. 



Calyx-tube mainly free from the ovary ; filaments shorter than the anthers ; styles 



distinct. 1. Hexastylis. 



Calyx-tube wholly adnate to the ovary ; filaments longer than the anthers : styles 

 united. 2. Asarum. 



Vines or erect leafy-stemmed herbs ; perianth irregular, deciduous ; anthers sessile. 



3. Aristolochia. 



1. HEXASTYLIS Raf. 



Perennial evergreen acaulescent herbs with glabrous or nearly glabrous foliage. 

 Rootstocks dichotomously branched ; roots fleshy. Leaves usually 1 every year, 

 the blades leathery, often mottled, petioled. Flowers solitary, on a pedicel aris- 

 ing from a membranous bract. Calyx glabrous without, the tube terete, some- 

 times inflated, the 3 segments shorter than the tube, valvate. Corolla none. Sta- 

 mens 12; filaments shorter than the anthers or wanting. Ovary mainly free from 

 the calyx-tube. Styles distinct, prolonged beyond the extrorse stigmas into cleft 

 appendages. Capsule free, sometimes distending the calyx-tube. Seeds flattened. 

 [Greek, referring to the six styles.] 



Leaf-blades mostly of an ovate or suborbicular type. 



Calyx-tube turbinate during anthesis. 1. H. heterophylla. 



Calyx-tube campanulate, cylindric-campanulate, sometimes constricted at the throat. 

 Calyx 2.5-5 crn - l° n g> much longer than thick. 2. H. Shuttleworthii. 



Calyx 1-2 cm. long, slightly longer than thick. 



Calyx campanulate at maturity, its segments about one-half as long as the 



tube. 3. H. Virginica. 



Calyx urn-shaped at maturity, its segments barely one-third as long as the 

 tube. 4- H. Memmingeri. 



Leaf-blades mostly of a hastate type. 



Calyx not constricted at the throat ; segments erect. 5. H. Ruthii. 



Calyx constricted at the throat ; segments spreading. 6. H. ari/olia. 



1. Hexastylis heterophylla (Ashe) Small. Ashe's Hexastylis. Leaf- 

 blades ovate to orbicular-reniform or triangular-ovate, 5-10 cm. long, acute or some- 

 times rounded or refuse at the apex, with a slightly open sinus; petioles as long as 

 the blades or twice as long; calyx 1-1.5 cm. long, the tubes turbinate at least dur- 

 ing anthesis, the segments 8-12 mm. broad, often nearly as long as the tube, 

 crisped, orange, purple or brown-purple without, brighter within ; prolongations of 

 the styles very stout, barely notched ; capsules hardly distending the calyx at 

 maturity ; seeds oval. In mountain woods, Va. to Ga. and Ala. March to May. 

 (Asarum heterophyllum Ashe.) 



2. Hexastylis Shuttleworthii (J. Britten) Small. Large flowered Hexa- 

 stylis. (I. F. f. 1279.) Leaf-blades ovate to suborbicular or rhombic-orbicular, 

 5-8 cm. long, apiculate or obtuse ; petioles as long as the blades or longer ; calyx 

 2.5-5 cm - l° n g '■> tne tu be cylindric-campanulate, the segments 1.5 2 cm. broad, 

 often abruptly acute, mottled within ; pedicels shorter than the diameter of the 

 calyx -tube ; prolongations of the styles stout, barely notched ; capsule hardly dis- 

 tending the calyx ; seeds triangular in outline. In high-mountain woods, Va. to 



* Contributed by Dr. John K. Small. 



