Aristolochia, Linnaeus, 1753

Key to identify the species of Aristolochia View in CoL with branched trichomes

1. Leaf lamina shallowly cordate, the sinuses broad and < 1 cm deep. Flowers usually 2 or more on each leaf axil. Utricle 1.7–2.5 cm long; limb narrowly ovate,> 4 cm long. Southern Ecuador; departments of Pasco and Piura ( Peru).................................. A. fosteri

- Leaf lamina deeply cordate, the sinuses narrow and> 1 cm deep. Flowers solitary, axillary. Utricle to 1.5 cm long; limb ovate to widely ovate, < 2 cm long. Departments of Apurimac, Cusco and Piura ( Peru), and Cochabamba, Chuquisaca and Santa Cruz ( Bolivia)..............................................................................................................................................................................................2

2. Petiole 2–3 cm long. Lobes of the leaf lamina parallel, not overlapping, forming sinuses to 1 cm in depth. Peduncle and ovary 2–3 cm long. Perianth limb very broadly ovate, strongly constricted and with fan-like veins internally at its base. Departments of Apurimac and Cusco ( Peru) ............................................................................................................................................. A. killipiana

- Petiole 3–6 cm long. Lobes of the leaf lamina convergent and overlapping, forming narrow sinuses 1–2.2 cm in depth. Peduncle and ovary 3.0– 5.4 cm long. Perianth limb ovate to widely ovate, slightly constricted and lacking fan-like veins at its base. Departments of Piura ( Peru), and Cochabamba, Chuquisaca and Santa Cruz ( Bolivia) .........................................................................................3

3. Leaf lamina membranaceous, lower surface not glaucous; basal veins prominulous and higher order veins prominulous to plane beneath, and apex acute. Pseudostipules broadly ovate, 4–8 × 3–6 mm. Utricle 8–12 mm long, 4–5 mm in diameter; syrinx c. 0.5 mm long; tube 6–12 mm long, 2–4 mm in proximal diameter, 5–8 mm in distal diameter; limb ovate, 1.4–2.0 cm long, apex acute to obtuse, sometimes mucronulate. Capsule c. 3 cm long, 1.2–1.5 cm in diameter. Seeds 4–5 × 4–5 mm, with a marginal, vestigial wing c. 0.5 mm wide, adaxial surface warty. Tucumano-Boliviana Province , departments of Cochabamba, Chuquisaca and Santa Cruz ( Bolivia), at elevations between approximately 1450 and 2580 m............................................................................. A. andina

- Leaf lamina chartaceous, lower surface glaucous; basal veins prominent and higher order veins densely reticulate beneath, and apex obtuse. Pseudostipules triangular, 3–4 × 2–2.5 mm. Utricle 1.3–1.5 cm long, 1.2–1.3 cm in diameter, syrinx 1.5–2 mm long; tube 1.6–2.4 cm long, 4–5 mm proximal diameter, 1–1.4 cm distal diameter; limb widely ovate, 0.8–1.4 cm long, apex obtuse to emarginate. Capsule 3.5–4.4 cm long, 1.5–2 cm in diameter. Seeds 5–6 × 5–6 mm, wingless, adaxial surface smooth. Seasonally dry forests of the Piura Department, Peru, at elevations between 1000 and 1590 m...................................................... A. guillermoi