ARISTOLOCHIACE^E. (BIRTHWORT FAMILY.) 371 



DIVISION III. APETALOUS EXOGENOUS PLANTS. 



Floral envelopes single, consisting of a calyx only, or alto- 

 gether wanting. 



ORDER 105. ARISTOLOCHIACEJE. (BIRTHWORT 

 FAMILY.) 



Herbs or woody vines, with alternate petioled mostly cordate and entire 

 leaves, and solitary peduncled dull-colored flowers. Calyx adherent to 

 the 6-celled ovary, tubular, valvate in the bud. Stamens 6-12, more or 

 less united with the styles : anthers adnate, extrorse. Fruit 6-celled, few 

 - many-seeded. Seed anatropous. Embryo minute, at the base of fleshy 

 albumen. 



1. ASARUM, Tourn. ASARABACCA. 



Calyx regular, 3-lobed. Stamens 12, the filaments partly united with the 

 style, and usually prolonged beyond the anthers. Capsule fleshy, globose, open- 

 ing irregularly Aromatic perennial herbs, with creeping stems, long-petioled 

 cordate or kidney-shaped leaves, and axillary peduncled flowers. 



1. ASARUM. Calyx bell-shaped, adnate to the ovary, 3-parted: filaments free or 

 nearly so : stigma 6-lobed. Leaves deciduous. 



1. A. Canadense, L. (WILD GINGER-ROOT.) Pubescent ; leaves 2, kid- 

 ney-shaped ; calyx-lobes acuminate ; filaments as long as the style. Mountains 

 of North Carolina, and northward. April and May. Flowers short-peduncled, 

 purple within. 



2. HETEROTROPA. Calyx inflated, nearly free from the ovary, 3-cleft: fila- 

 ments united with the ovary: styles 6 : stigmas 2-cleJl. Leaves evergreen, smooth, 

 mottled. 



2. A. Virginicum, L. Leaves round-cordate ; calyx inflated-bell-shaped, 

 with rounded lobes; stigmas deeply 2-cleft. Rich shady woods in the upper 

 districts, Georgia, and northward. April and May. Leaves single or 2-3 

 together, 2' long. Flowers 8" - 9" long, nearly sessile at the base of the petioles, 

 greenish without, dull purple within. 



3. A. arifolium, Michx. Leaves oblong-cordate; calyx pitcher-shaped, 

 with rounded lobes ; stigmas slightly 2-cleft. Shady woods in the lower dis- 

 tricts, Florida to North Carolina. March and April. Leaves 3' -4' long, 

 auriculate at the base, long-petioled. Calyx 1' long, distinctly peduncled, con- 

 tracted above the middle, dark purple within. 



2. ARJSTOLOCHIA, Tourn. BIRTHWORT. 



Calyx tubular, commonly bent and inflated above the ovary. Anthers 6, ses- 

 sile, adnate to the 3 - 6-lobed or angled stigma. Capsule 6-valved. Erect or 



