Flora of North America species comparison

perennial, climbing, branching zigzag, terete, 5–9 m × 5–8 mm, woody, glabrous;

prickles numerous, sparse or absent distally, flattened, rigid, stout, to 4 mm.

perennial, climbing or not, to 12 m, woody, glabrous;

prickles sometimes absent distally, bristlelike, 3–11 mm, flexible.

evergreen;

petiole 0.5–1.2 cm;

blade green abaxially, drying to brownish green, narrowly ovate to ovate-elliptic, with 3 prominent veins, secondary veins obscure to prominent, 4.5–6(–8.5) × 2–3.5 cm, not glaucous, glabrous or minutely pubescent abaxially, base auriculate, pandurate, or rounded, cuneate at insertion of petiole, margins entire, apex acute to abruptly deflexed point.

evergreen, ± evenly dispersed;

petiole 0.5–2 cm;

blade dull green, drying to dull, ashy green, ovate to broadly ovate, conspicuously veined, 4–11 × 3–8 cm, not glaucous, glabrous, base cordate to subcordate;

margins entire, thin, flat, not banded, never lobed;

apex acute, often apiculate.

3–8, terminal, axillary to leaves, 5–8(–25)-flowered, loose;

peduncle 0.2–1.5 cm.

axillary to distal leaves, (2–)8–13(–19)-flowered;

peduncle 2–5 cm, longer than petiole of subtending leaf.

perianth green;

tepals: staminate 6–8 mm, pistillate 3–4 mm;

ovule 1 per locule;

pedicel 0.2–1 cm.

perianth green;

tepals 3–6 mm;

ovule 1 per locule;

pedicel thin, 1–1.5 cm.

purplish maroon, purple, or black, ovoid to flattened, 5–7 mm, glaucous.

black, ovoid, 7–9 mm.

;

rhizomes linear or dense masses of potatolike tubers.