Woody or herbaceous vines or less often perennial herbs or shrubs, sometimes arising from tubers or from fleshy roots; nodes 3-lacunar. Leaves alternate, simple and mostly entire, sometimes lobed; stipules wanting, a pseudostipule present in the leaf axil in some South American species. Flowers solitary, or in terminal or lateral racemes or cymes, perfect, actinomorphic or zygomorphic, mostly epigynous, otherwise hemi-epigynous or perigynous, often smelling like rotting meat; calyx synsepalous, tubular at least below, actinomorphic and 3-lobed to zygomorphic and 3-lobed to 1-lobed or not lobed, often large and colourful; petals wanting, much reduced or well developed (Saruma); stamens 4-many, anthers dithecal and tetrasporangiate, extrorse; gynoecium of 4-6 carpels; ovary 4- to 6-locular, or with 4-6 incomplete partitions, placentation axile or parietal; ovules numerous, crassinucellar and mostly anatropous; endosperm development cellular. Fruits usually capsular, rarely follicular or indehiscent; seeds with abundant, oily endosperm; embryo very small, sometimes undifferentiated, basal.
Guianas: present Neotropics: present Throughout the world in tropical and temperate regions: present
Throughout the world in tropical and temperate regions; an estimated 650 species in 6-7 genera (3 monospecific), most of the species (about 550) belong to
Aristolochia, and most of the remaining (about 75) to the north temperate genus Asarum; in the Neotropics probably about 250 species in 3 genera; in the Guianas 18 species in one genus. Aristolochia platyloba Garcke, Linnaea 22: 69. 1849 = Aristolochia surinamensis Willdenow Aristolochia macrota Duchartre, Ann. Sci. Nat., ser. 4, 2: 43. 1854 = Aristolochia surinamensis Willdenow Aristolochia macrota Duchartre, Ann. Sci. Nat., ser. 4, 2: 43. 1854. Lectotype here designated: Rob. Schomburgk I 679 (lectotype G-DC, photo, F, US, isotypes BM, F, K (2 sheets), US). Aristolochia rodriguesii Hoehne, Mem. Inst. Oswaldo Cruz 20(1): 76 (140), tab. 72. 1927. Lectotype here designated: Brazil, Ule 9338 (lectotype MG). Howardia schomburgkii Klotzsch, Monatsber. Konigl. Preuss. Akad. Wiss. Berlin 1859: 613. 1859. Neotype here proposed: Guyana. Pirara, Rich. Schomburgk II 414 (holotype P, isotype BM, K). Aristolochia weddellii Duchartre subsp. rondoniana Hoehne, Arch. Bot. Est. Sao Paulo 1(1): 19, tab. 8. 1925. Lectotype here designated: Brazil, Comm. Rondon 2445 (lectotype SP, isotype RB).