[O. c. var. lupulina (Knuth) Zucc.; O. c. f. purpurea (Pari.) Knuth; O. c. var. purpurea Pari.; O. c. var. vis- cidula Wieg.; O. lupulina Kunth]
(pol?) Yellow wood sorrel, (ihi ‘ai, (ihi ‘awa, ‘ihi maka ‘ula, *ihi makole
Caulescent perennial herbs, primary root sometimes becoming thickened and woody; stems several from the main root, ascending to erect, rooting at the nodes, strigillose to sometimes also villous. Leaves scattered, trifoliolate, leaflets broadly obcordate to elliptic-obcordate, the lobes rounded, 0.4- 2(—2.5) cm long, 0.5-2(-2.5) cm wide, glabrous to sparsely or moderately villous, especially on margins and lower surface, petioles 1 —6(— 10) cm long, stipules inconspicuous, rarely up to 3 mm long. Flowers 1—5(—8) usually in umbellate cymes, hetero- stylous, bracts 2 to several; sepals lanceolate, 2-6 mm long, sparsely strigillose, sometimes with multicellular hairs; petals yellow, spatulate, 4-10 mm long, apex rounded to emarginate; ovules (1—)5—11 per cell, in 1 row. Capsules cylindrical or sometimes narrowly ellipsoid, 9-20(-24) mm long, sparsely to densely pubescent with multicellular hairs. Seeds brown, compressed-ovoid, ca. 1 mm long, the surface with 7-10 transverse ridges. [2n = 24, 28, 44, 48.] Cosmopolitan species of unknown origin; in Hawaii occurring in open, disturbed sites in coastal to subalpine habitats,0-2,300 m, on Midway Atoll and all of the main islands. It may represent a Polynesian introduction or an indigenous species, as it was collected by the first botanist to visit the Hawaiian Islands, David Nelson, in 1779 (,Nelson s.n., BM). Further support for pre-contact introduction is given by the discovery of seeds of this species in archae-ological remains in the Mauna Kea adze quarry complex (Allen, 1981). This site was abandoned prior to contact (1778).— Plate 142.
Oxalis corniculata has been used medici-nally in Hawai‘i according to information on collection labels (1934, Handy s.n., and 1931, Pukui s.n., BISH). It is an extremely complex and variable species and many infraspecific taxa have been described, yet nearly all are linked by various intermediate forms. At present it does not seem likely that the variation of this species in Hawai‘i can be attributed to separate introductions from different parts of the world, as indirectly suggested by St. John (1973a), who recognized several varieties.