AUISTOLOCUIACE.E. (BIRTHWORT FAMILY.) 371 



Division III. APETALOUS EXOGENOUS PLANTS. 



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

 getlier wanting. 



Order 10.3. ARISTOLOCHIACEiE. (Birtiiwort 

 Family.) 



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

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

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

 less united with the styles : anthers adnate, extrorse. Fruit G-eelled, few 

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

 albumen. 



1. ASARUM, Tourn. Asararacca. 



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 

 eordate or kidney-shaped leaves, and axillary peduneled 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 Gixger-root.) Pubescent; leaves 2, kid- 

 ney-shaped ; calyxdobes 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-c/eft .- fila- 

 ments united with the ovary : styles 6 : stigmas 2-clcft. — Leaver evergreen^ smooth, 

 mottled. 



2. A. Virginicum, L. Leaves round-cordate; calyx inflatcd-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. arifolilim, Michx. Leaves oblong-cordate; calyx pitcher-shaped, 

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

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

 anriculate at the ba-e, lomr-petioled. Calyx 1' long, distinctly peduneled, con- 

 tracted above the middle, dark purple within. 



2. ARISTOLOCHIA, Tourn. Bibthwort. 



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

 sile, adnate to the 3- 6-lobcd or angled stigma Capsule 6-vulvcd. — Erect or 



