[Malva coromandeliana L; Malvastrum tricuspida- tum (R. Br.) A. Gray; Sida fauriei H. Lev.; S. oahuensis H. Lev.]
(nat) False mallow
Annual or perennial herbs 0.2-1.5 m tall, pubescence predominantly of simple and appressed, bilateral, 4-armed hairs. Leaf blades lanceolate to broadly ovate, usually 2.5-5(—11) cm long, rarely slightly 3-lobed, margins serrate to dentate, apex acute, base truncate to broadly cuneate. Flowers axillary, 1-3 together, or in racemose glomerules, sometimes congested apically; involucral bracts lanceolate, 4-6 mm long, adnate basally to calyx; calyx 5-7 mm long at anthesis, 7-12 mm long in fruit; corolla pale yellow to yellowish orange, rotate, 15-24 mm in diameter; staminal column up to 2.5 mm long, glabrous. Schizocarp reddish brown, 5-7(-9) mm in diameter, mericarps (9)10-14(15), 1.5-3.5 mm high and 2-4 mm wide, indehiscent, with a ventro-apical spine 0.2-2 mm long and 2 dorso-apical cusps, 0.1-1.2 mm long, hispid apically, endoglossum absent. Seeds 1.5-2 mm long. [2n = 24.] Pantropical, primarily in alkaline soils at low elevations; in Hawaii naturalized in disturbed sites, 3-610 m, on Midway Atoll and all of the main islands. First collected on 0‘ahu in 1864-1865 (Mann & Brigham 18, BISH).—Plate 125.
Hill (1982) recognizes three subspecies in Malvastrum coromandelianum. Only subsp. coromandelianum has been col-lected in Hawaii. It is distinguished from the other subspecies primarily in having the mericarps 3-3.5 mm high and 3.5-4 mm wide, the ventro-apical spine 0.8-1 (-2) mm long, and dorso-apical cusps 0.5-1.2 mm long.