Oxalis pes-caprae L.
Bermuda buttercup
Perennial herb, apparently acaulous but with underground stolons bearing numerous bulbils near the apex; contractile roots thick, fleshy, glassy white; bulb to c. 3 cm long, ovoid; tunic pale brown, 5-7-nerved. Lvs 3-foliolate, radical. Petiole 6-22 cm long, ± hairy; stipules membranous, glabrous or nearly so. Lamina sessile (that of terminal leaflet somewhat larger than laterals), 10-32 × 12-35 mm, shallowly to deeply 2-lobed to c. 1/2 way, glabrous above, ± sericeous and finely reticulate below; base narrow-cuneate; lobes oblong to almost obovate; apex rounded. Fls (1)-3-18, in pseudoumbels, pendent; peduncles (7)-15-45 cm long, glabrous to sparsely hairy; pedicels to 2 cm long, densely clothed in glandular hairs. Bracts at base of pedicels, c. 2.5 mm long, lanceolate, hairy, with apical calli. Sepals 5-6.5 mm long, lanceolate or oblong-lanceolate, with glandular hairs mainly towards base, or nearly glabrous; calli 2, apical, usually orange, sometimes yellow. Petals (1.5)-2-2.8 cm long, obovate with narrow claw, golden, sometimes red-margined, with appressed hairs outside or almost glabrous. Stamens at 2 levels, glabrous; filaments appendaged below, c. 7 mm long in the 2 common stylar morphs, 5 mm long in the rare long-style morph. Styles either < or nearly = lower stamen whorl (short-styled clone), > lower stamen whorl (mid-style clone), or = or > upper stamen whorl (long-style clone), hairy. Capsule not seen.
N.: a common to abundant weed in lowland areas; S.: Marlborough, Nelson, less common in coastal Canterbury.
South Africa 1883
Waste places in and around settlements, disturbed soil on roadsides, cultivated soil, often forming dense stands and a serious garden weed, occasionally in open pockets in scrub on cliffs and banks.
FL Jan-Dec.
Possibly poisonous (Connor 1977).
Bermuda buttercup does not form seed in N.Z., although there are 3 stylar morphs (clones) which may grow together. The mid-style morph has dark purple or dark red sepal tips and, unlike the short-styled plant, is a problem weed in Australia (P. W. Michael, pers. comm.). The same form appears to be the worst one in N.Z. also. Bermuda buttercup is a bad weed in many warm temperate or subtropical countries. The sp. has previously been known in N.Z. as O. cernua.
The closely related, yellow-flowered O. compressa L. f., with flattened petioles, was recorded from N.Z. in 1883 by Cheeseman, but no specimens have been found. O. bowiei Lindley is also in sect. Cernuae and has been recorded wild once in N.Z. (see under key).
