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Oxalis flava L. Sp. Pl. I (1753) 433. (A group species) Salter #114
O. pectinata Jacq.
O. flava L. vars. Thunbergiana Sond. and pectinata Sond.
(Further synonymy given under the different Forms).
Rather robust, 3-25cm high, usually entirely glabrous, the stem not or rarely exserted.
Bulb: oval or ovoid, 1.5-4cm long : outer tunics thin, soft, pale brown, or rarely splitting and forming a dense fibrous coating.
Rhizome: stout, usually long, with several conspicuous amplexicaul scales, often enclosed within a brown tunicaceous cortex.
Leaves: few or many, often spreading : petioles commonly 2-6cm long, dilated and scale like below the basal articulation, swollen into a small pulvinus at the apex, very rarely pilose with short patent pluricellular hairs : leaflets 2-12, (in Form G. the juvenile leaf simple), sessile, often spreading palmately, linear, oblong, cuneate, cuneate-obovate or obovate, acute, obtuse or more rarely emarginate, often conduplicate-falcate, 1-5cm long, the margins sometimes more or less cartilaginous and rarely undulate, in Form G often purplish beneath.
Peduncles: 1-fld, shorter or longer than the leaves, with 2 alternate linear bracts near the calyx.
Sepals: ovate-lanceolate, oblong or ovate-oblong, acute or obtuse, 0.4-1cm long, often unequal in width, in Form D. 1-2 longer and subspathulate, very rarely glandular-ciliate, usually with several indistinct orange calli near the apex.
Corolla: 1.4-3cm long, yellow, white or very pale rosy-violet, with a rather broadly funnel-shaped yellow tube : laminae of the petals obovate, often purple on the outer margin beneath, rather longer than the attenuate claw.
Filaments: very minutely glandular-pilose, the shorter 2.5-4.5mm, the longer 3.5-7.5mm long, with obtuse teeth.
Ovary: glabrous, the chambers 2-3 ovuled : styles glandular- pilose on the upper half.
Capsule: subglobular. Seeds without endosperm.
Form A.
Typical.
Leaflets: linear or oblong.
Flowers: May - June.
Form B.
Petioles (and rarely Peduncles): clothed with short pluricellular hairs.
Form C.
Leaves: linear-oblong. Intermediate between O. flava L. and O. lupinifolia Jacq. (Form E.)
Form D.
O. flabellifolia Jacq.
Sepals: one or two spathulate or oblong, obtuse, longer and broader than the remainder
Flowers: May.
Form E.
O. lupinifolia Jacq.
Leaflets: 3-8, obovate or cuneate-obovate, acute, rounded or slightly emarginate at the apex, more or less cartilaginous and sometimes undulate on the margins.
Form F.
Petiole: with narrow cartilaginous margins.
Leaflets: often with undulate margins.
Corolla: yellow or pale mauve.
Bulb: comparatively shallow, not producing a specialised descending root : tunics numerous, fibrous, splitting.
A very variable form.
Form G.
Juvenile leaf simple.
Petiole: without wings : leaflets 1-5 rarely 6, with cartilaginous margins.
Corolla: yellow.
(i) Leaflets cuneate or oblanceolate, coriaceous.
(ii) Leaflets broadly cuneate to suborbicular, thinner in texture.
Perhaps intermediate with O. fabaefolia Jacq Form B. (O. asinina).
Form H.
Leaflets: linear.
Bulb: comparatively shallow, not producing a descending specialised root : tunics numerous, fibrous, splitting.
A mountain form.
A variable group-species, common in the western coastal belt and consisting of many micro-varieties. The specimens cited here have been grouped under the Forms A to H, each showing some more or less salient character, but there is some overlapping and the grouping cannot be considered of definite taxonomic value.
In most of the Forms plants with the white or pale rosy- violaceous corolla are nearly as common as those with the yellow, the two colours sometimes growing in separate colonies or districts, but just as often in association. The width of the leaflets varies considerably under different epharmonic conditions and often increases considerably after the flowering period. O. pectinata Jacq. usually with longer leaflets, is a very slight variant.
Although there is a general tendency towards the production of more leaflets in the Forms where the leaflets are narrow, it has not been found possible to co-ordinate the number of leaflets, which varies on the same plant, with any other constant characters. In the colong near Nieuwoudtville, with linear leaflets, the leaflets varied from 2-4 only on all the plants, but very similar colonies occur in the same district with a more normal number.
The specimens cited under Form C. are on the border line between O. flava and O. lupinifolia. Of those under Form D. (O. flabellifolia) , disregarding the inconstant and monstrous character of the unequal sepals, which occur in other species, some are nearer to O. flava and some to O. lupinifolia. The sepals are not necessarily recurved as figured by Jacquin.
Certain forms with cartilaginous-winged petioles (Form F), though differing considerably among themselves, show a tendency to merge into Form B of O. fabaefolia Jacq.
The specimens cited under Form G. although their petioles are not winged, are known to produce simple juvenile leaves and are also possibly related to O. fabaefolia.
Of the glandular ciliation of the sepals of O. flava, as figured by Jacquin in Oxal. t. 72, the only trace I have seen is on a few of the specimens and even there it is very scanty.