Mimosa pudica

Herbs or subshrubs, erect or decumbent, 0.3–1 m, armed. Stems ribbed to striate, hispid or glabrous; prickles infrastipular, paired, also sparse along internodes, recurved. Leaves: 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. Peduncles 1–3 cm. Inflorescences 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. Pedicels 0 mm. Flowers 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. Legumes 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. Seeds 2–5, ochre, lenticular, 3–3.2 × 2.5–3 × 1–1.2 mm, testa smooth or porous, fissural line 90%.

Phenology: Flowering Jul–Jan; fruiting Jul–Jan.
Habitat: Pinelands, secondary vegetation, burned or cleared pinelands.
Elevation: 0–40 m.

Introduced; Fla., Md., Mexico, West Indies, Central America, South America, introduced also in tropical Asia, Africa, Australia.

Discussion

Mimosa pudica is a pantropical species that has become established in Florida; C. F. Reed (1964) included M. pudica in the flora of the chrome and manganese ore piles at Canton, in the Port of Baltimore, Maryland; his record from Newport News, Virginia, cannot be verified, as that is an immature plant, probably corresponding to another species.

Varieties of Mimosa pudica were distinguished by J. P. M. Brenan (1959) in tropical East Africa. R. C. Barneby (1991) proposed a modified key to varieties; however, they are not clearly delimited in American populations. Available specimens from the flora area cannot be determined at the infraspecific level.

Selected References

None.

Lower Taxa