Flora of New Zealand Series

creeping oxalis

Perennial; primary root slender to stout, occasionally to c. 10 mm thick. Stems glabrous to densely hairy (hairs usually antrorse, occasionally dense and patent), ± filiform, creeping, prostrate or nearly so, rooting at nodes, much-branched and often mat-forming. Lvs 3-foliolate. Petiole 5-40 mm long, with patent or antrorse hairs, these sparse to dense; stipules adnate, truncate or rounded at apex. Petiolules very short. Lamina of leaflets equal, 1-9 × 1.5-12 mm, obcordate, sometimes broadly so, with width > length, with narrow to broad sinus and rounded lobes, glabrous or hairy above, glabrate or with appressed hairs beneath, ciliate or eciliate, often purplish below; calli 0. Fls solitary, rarely paired; peduncle glabrate to densely clothed in antrorse hairs, generally geniculate at apex; pedicel (4)-8-25 mm long. Bracts 1-3 mm long, ± linear-subulate, hairy, situated at base or at middle of pedicels; calli 0. Sepals 2.3-3.5-(4) mm long, oblong-lanceolate, oblong, or ovate-elliptic, glabrate or with antrorse hairs; calli 0. Petals 4.5-9-(13) mm long, ± oblong-obovate, yellow, often pink-flushed outside, glabrous. Stamens at 2 levels, glabrous or nearly so; filaments united at base, those of longer whorl c. 1.5 mm long. Styles < or > longer stamens, densely hairy. Capsule (3)-7-10-(13) mm long excluding styles, broadly cylindric, cylindric-ovoid or conic, glabrous to densely hairy; hairs short, patent or retrorse, sometimes glandular. Seed 1-1.3-(1.5) mm long, broad-ellipsoid; transverse ridges 7-13, subacute, sometimes white-topped; grooves deep.

N.; S.; St.; K.

Also indigenous to Australia and probably Norfolk Id.

Open rocky slopes, rock crevices, stony ground, old screes, short turf, poor or open pastures and tussockland, open scrub, cliff faces, river beds, beaches, waste places, lawns, plantations, cultivated ground, common to abundant, sea level to c. 1500 m.

FL Jan-Dec.

As indicated in the description O. exilis is a variable sp. in N.Z. The chief variation is in the degree of hairiness, alignment of hairs, lf size, stipule apex, corolla size, and capsule length and shape. Populations from montane to alpine areas growing in very rocky places, fellfield, rock crevices and old screes may constitute a distinct taxon; the plants have petioles with scattered hairs, ± truncate stipule apices, larger corollas than the common lowland plant of modified habitats and broad-cylindric capsules densely covered with retrorse or sometimes spreading hairs (e.g., CHR 394424, Haldon Hills, Marlborough, Druce, Apr. 1987). However, more detailed studies are required before this entity can be accorded formal recognition.

O. exilis is by far the commonest sp. of sect. Corniculatae in N.Z. and is almost certainly indigenous. This sp. was treated by Allan (1961) as O. corniculata var. microphylla Hook. f. and O. corniculata var. ciliifera (Cunn.) Hook. f.