Phaseolus acutifolius
tepary bean
weak or vigorous twiners, often trailing, to 400 cm.
stipules ascending, triangular to oblong, 1.5–3 × 0.5–2 mm;
petiole 2–8 cm;
rachis 0.5–2.5 cm;
stipels linear to lanceolate, often clavate, 1.3–2 mm, 1-veined;
leaflet blades linear to lanceolate or ovate to widely ovate, often weakly to conspicuously lobed on one or both sides basally, 2.5–11.5 × 0.3–5 cm, membranous to rigid, venation often prominent, base rounded or truncate to cuneate, apex acute to attenuate, surfaces abaxially sparsely to densely covered with minute, uncinate hairs, with incumbent hairs along veins and marginally, adaxially covered with sparsely incumbent and uncinate hairs.
to 26 cm;
main axis sparsely to densely covered with uncinate hairs;
rachis 2–24 cm, with 2–6 usually biflorous nodes;
peduncular basal bracts linear to lanceolate, 1–1.5 × 3–5 mm;
primary bracts ovate to lanceolate, 2–3 × 0.5 mm, 1–3-veined.
0.8–11.5 cm.
3–7 mm, covered with minute uncinate hairs;
bracteoles persistent, linear to lanceolate, 1.5–1.8 mm.
calyx campanulate, 3–4 mm, sparsely covered with incumbent and uncinate hairs;
abaxial and lateral lobes triangular to lanceolate;
adaxial lobes usually connate into apiculum;
corolla pink to lavender, violet, or purple, 10 mm;
banner suborbiculate, 7–8 mm, apex emarginate, rarely adaxial surface covered with straight hairs;
wings obovate to oblong, 10–12 mm, base slightly constricted, apex obtuse;
keel 6 mm;
ovary linear, 4 mm, covered with appressed hairs.
pendent, compressed, linear-falcate, 32–70 × 5–9 mm, elastically dehiscent, valves thin to papery, sparsely covered with appressed and uncinate hairs.
3–6(–10), brown to ivory, punctate and mottled with black, oblong, 3–6 × 2.5–5.5 mm, smooth to slightly rugose;
hilum ovate, 0.5–1.2 mm.
annual, with narrow, fibrous roots.
Phaseolus acutifolius
Varieties 2 (2 in the flora).
Both varieties of Phaseolus acutifolius often occur in the same habitats, although var. tenuifolius is more often associated with open and drier areas.
Phaseolus acutifolius in the broad sense is a widespread polymorphic assemblage that shows a seemingly continuous series of variants that have developed marked leaflet differences toward the extremes of an almost continuous range. M. W. Blair et al. (2012) have recently established, with molecular evidence, that both varieties show evidence of intercrossed individuals.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Leaflet blades ovate to widely ovate, apex acute, base rounded; terminal leaflet blades 2.5–8.5 × 1–5 cm; legumes 36–70 × 5–9 mm; seeds 4–10, 3–6 × 3.3–5.5 mm. | var. acutifolius |
1. Leaflet blades linear to lanceolate, apex acute to attenuate, base truncate to subtruncate; terminal leaflet blades 3.5–11.5 × 0.3–2.3 cm; legumes 32–54 × 5–6 mm; seeds 3–6, 3–4.5 × 2.5–4.5 mm. | var. tenuifolius |
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