Herbs perennial; annual growth modules consisting of 2-4 cataphylls, 1 or 2 foliage leaves, and a terminal flower. Rhizomes short and vertical or long and horizontal; rhizomes and roots often pungently aromatic. Stems herbaceous. Foliage leaves solitary or paired on each growth module (when paired appearing opposite), usually long petiolate, often cordate or sagittate, margin entire. Flowers terminal, solitary (rarely paired). Perianth uniseriate, actinomorphic (rarely slightly zygomorphic). Calyx adnate to ovary to varying degrees; sepals either connate beyond attachment to ovary and forming a tube or free and forming false tube above ovary; tube cupular, urceolate, campanulate, funnelform, or cylindric, often ribbed or tessellate on adaxial surface, constricted or open at throat (orifice), throat with or without narrowly projected, contiguous shelf of tissue (orifice ring); lobes 3, erect, spreading, or reflexed. Stamens 12 in 2 series, rarely with 3 staminodes; filaments long to almost absent; anthers extrorse. Ovary inferior or half-inferior, 6-loculed; carpels fully connate. Styles 6, free or united into column, apex entire or 2-lobed; stigma terminal or lateral. Fruit a fleshy or spongy capsule, splitting irregularly when ripe. Seeds convex dorsally, plane or grooved ventrally, with fleshy funicle at base. 2n = 12, 24, 26.

Source: [
• 1
]. 

Herbs , perennial, deciduous, rhizomatous, without aerial stems. Leaves alternate (sometimes appearing opposite because of crowding), 2-ranked; stipules absent; petiolate foliage leaves and sessile, triangular scale-leaves both present. Leaf blade membranous or leathery, pubescent at least abaxially and on margins. Inflorescences terminal on rhizome, flowers solitary; bracts absent. Flowers: sepals distinct, usually mixture of white, green, tan, red, or purple, proximally touching valvately and forming well-defined false tube, externally usually villous, inner surface strigose, smooth or with weak longitudinal ribs, never with network of low ridges; vestigial petals present or absent; stamens 12, distinct; filaments longer than pollen sacs; terminal appendage of anther well developed; ovary inferior, 6-locular; styles connate in column. Capsule fleshy, dehiscence irregular. Seeds ovoid, not winged, with fleshy appendage. x = 13.

Source: [
• 2
]. 

"Cal regular, tubular below, deeply 3-lobed, hairy outside; pet none or vestigial; stamens 12, with well developed filament, closely appressed to the styles; connective prolonged as a subulate tip; ovary inferior, 6-locular; styles coherent in a column, expanded at the tip into a 6-lobed stigma; fr capsular, opening irregularly; seeds large, ovoid, wrinkled, carunculate; herbs, the elongate rhizome producing annually a pair of petiolate, broad, membranous, hairy lvs, these deciduous at the end of the season; fls solitary, red-brown, short-peduncled, arising between the pair of lvs. 90, N. Hemisphere."

Source: [
• 3
]. 

SELECTED REFERENCES

Mesler, M. R. and K. L. Lu. 1990. The status of Asarum marmoratum (Aristolochiaceae). Brittonia 42: 33-37.

Source: [
• 2
].