Mimosa hystricina
Phytologia 76: 414. 1994.
Subshrubs, prostrate, 0.5–1 m, armed. Stems ribbed, glabrous or puberulent; prickles along ribs, recurved. Leaves: stipules linear to filiform, 5–8 mm, puberulent; petiole 2–5 cm; primary rachis (3–)5–6 cm; pinnae 3–5 pairs; leaflets 11–17 pairs, blades obliquely oblong to elliptic, 4–7 × 1.5–2.5 mm, margins ciliate, reticulate veins prominent abaxially and adaxially, apex acute, mucronate, surfaces glabrous. Peduncles 7–13 cm. Inflorescences 100–180-flowered, axillary, globose capitula, solitary, 20–30 mm diam.; bracts linear, 3/4 or equal to corolla length. Pedicels 0.2–0.5 mm. Flowers bisexual and staminate; calyx campanulate, lobes 5, 1/9–1/7 corolla length; corolla purplish pink, glabrous, lobes 5, 1/4–1/3 corolla length; stamens 10, filaments connate at bases, pink; ovary stipitate, glabrous; style attenuate at apex; stigma tubular. Legumes stipitate, straight, linear-oblong, tetragonal, 20–45 × 8–10 mm, not constricted between seeds, valves entire, 3–6 mm wide, margin 2–4 mm wide, prickly, prickles connate at bases, apex acute, obtuse, or rostrate, rostrum 2–4 mm, faces glabrous; stipe 1–1.5 mm. Seeds 5–14, reddish brown, lenticular or rhomboid, 4–4.9 × 3.6–3.9 × 2–2.5 mm, testa porous, fissural line 90%.
Phenology: Flowering (Jan–)Mar–Jun(–Oct); fruiting (Mar–)May–Jul(–Nov).
Habitat: Dry sandy soils, pine-post oak hills, moist grassy fields in pinewoods areas.
Elevation: 0–100 m.
Discussion
Mimosa hystricina occurs in Allen, Beauregard, and Calcasieu parishes in southwestern Louisiana, and in southeastern Texas. Flowering plants are difficult to distinguish from M. nuttallii; the latter is more common in Missouri and Texas.
Selected References
None.