Oxalis compressa var. compressa
Winged Wood-sorrelHerb without stems; bulbs ovoid, 8–15(–30) mm long, pointed, tunics pale brown; bulbils formed on white fleshy rhizome and in lower leaf axils. Leaves crowded, 3-foliolate; leaflets subsessile, cuneate-obcordate, 10–30 mm long, 15–35 mm wide, bilobed, green, glabrous above, sparsely pubescent below, margins ciliate, sinus to c. one-quarter leaflet length, lobes oblong, divergent, apices rounded, 10–35 mm apart; petioles 1.2–20 cm long, dorso-ventrally compressed and narrowly winged, sparsely to moderately hairy on margins only or the whole petiole, the hairs usually patent or sometimes mixed with underlying appressed or ascending simple antrorse hairs; stipules membranous, narrow, to c. 10 mm long, abruptly tapering into petiole. Inflorescences basal, (1–)3–6(–10)-flowered; peduncles longer than leaves, 10–20(–31) cm long indumentum similar to petioles, but less hairy; pedicels covered with a mixture of antrorse simple hairs and spreading glandular hairs. Sepals lanceolate, 5–7 mm long, indumentum similar to pedicels, green at base, reddish at apex, usually with 2 orange apical calli. Petals 15–20 mm long, yellow. Capsules not developed in Australia. Aug.-Nov.
VVP, GipP, CVU. Also naturalised WA, SA. Native to the Cape Province, in South Africa. Currently confined to degraded sites in grassland dominated by introduced species at Broadmeadows Valley Park, where it is very common, and at the grounds of the Arthur Rylah Institute, Heidelberg.
Easily mistaken for the much commoner Oxalis pes-caprae, from which it differs in having conspicuously dorsiventrally compressed and winged petioles, hairier petioles than those of O. pes-caprae, generally fewer-flowered inflorescences, and generally lower-lying leaves.