Flora of North America species comparison

terete, tomentulose or glabrescent;

prickles infrastipular, paired, usually recurved, rarely straight.

ribbed to striate, hispid or glabrous;

prickles infrastipular, paired, also sparse along internodes, recurved.

stipules linear to subulate, 2–4 mm, puberulent;

petiole 0.1–0.7 cm;

primary rachis 0.3–2 cm;

pinnae 2–8 pairs;

leaflets 5–9(–12) pairs, blades obliquely oblong, 2–4 × 0.4–1.3 mm, margins ciliate, reticulate veins slightly visible abaxially, apex acute to obtuse, surfaces puberulent or glabrous abaxially, glabrous adaxially.

stipules lanceolate, 7–12 mm, glabrous to sparsely setose;

petiole 1–4.5 cm;

primary rachis 0–2.5 mm;

pinnae 1 or 2 pairs, digitate;

leaflets 15–25 pairs, blades obliquely linear-oblong, 5–10 × 2–2.5 mm, margins setose, 1 eccentric vein prominent abaxially, apex acute to mucronate, surfaces glabrous.

17–40-flowered, axillary, globose capitula, solitary or in fascicles of 2 or 3, 8–12 mm diam.;

bracts spatulate, 1/4–1/2 corolla length.

95–125-flowered, axillary, globose or subglobose capitula, solitary or fascicles of 2 or 3, also disposed in racemiform branches, 10–15 mm diam.;

bracts linear to lanceolate, 1/2–2/3 corolla length.

0.7–1.5 cm.

1–3 cm.

0 mm.

0 mm.

bisexual;

calyx campanulate, lobes 5, (1/3–)1/2–3/4 corolla length;

corolla white or purplish pink on lobes, tomentose or tomentulose, lobes 5, 1/4–1/3 corolla length;

stamens 10, filaments distinct to bases, white;

ovary stipitate, glabrous or pubescent;

style attenuate at apex;

stigma poriform.

bisexual;

calyx campanulate, lobes 4, 1/10 corolla length;

corolla pink, glabrous, lobes 4, 1/4 corolla length;

stamens 4, filaments distinct to base, lilac;

ovary sessile to shortly stipitate, glabrous;

style attenuate at apex;

stigma poriform.

sessile or stipitate, straight or curved, linear, 25–45 × 3–4 mm, constricted between seeds, valves entire, margin prickly or unarmed, apex acute to acuminate, faces glabrous;

stipe 0.5–1.5 mm.

sessile, straight, linear-oblong, 10–15 × 3–4 mm, constricted between seeds, valves with 2–5 segments, margin armed, long-setose, apex acuminate, faces glabrous.

3–8, dark brown, oblong, 3.5–6 × 2–2.7 × 1–1.8 mm, testa smooth or porous, fissural line 40–50%.

2–5, ochre, lenticular, 3–3.2 × 2.5–3 × 1–1.2 mm, testa smooth or porous, fissural line 90%.