Oxalis stricta L., sheep showers, dillen’s oxalis, gray–green wood sorrel. Perennial herb, taprooted with old lower stems fibrous–rooted, not rosetted, 1—several–stemmed at base, initially erect, older axes decumbent with erect shoots and suberect to ascending lateral branches, sometime somewhat mat–forming, 5—25 cm tall; shoots with basal leaves and cauline leaves, shoots at night at night or during water stress with leaflets moving downward and folding along leaflet midribs fully reflexed and touching, pubescent.
Stems cylindric, < 2 mm diameter (erect stems) and 2.5 mm diameter (basal stems), strigose to short–strigose, basal stems aging purplish red.
Leaves helically alternate, palmately 3–foliolate, long–petiolate, without stipules (stipules obscure); petiole ascending, to 55 mm long, with conspicuous construction near base, below constriction flaring and broadly attached to stem, to 2.5 mm long, sparsely hairy with hairs to 1 mm long, above constriction with pulvinus, above pulvinus flat on upper side and < 1 mm diameter, sparsely short–strigose with upward–pointing hairs; petiolule = pulvinus, 0.6—0.8 mm long, reddish, short–hairy; blades of leaflets inversely heart–shaped, 4—12.5 × 5.5—18 mm, length < width, tapered at base, entire with rounded lobes, deeply notched at tip < 1/3 to base, pseudopalmately veins with principal veins slightly raised on lower surface, upper surface flat, dull, with scattered short hairs, lower surface short–strigose.
Inflorescence umbel–like cyme, axillary, erect, 1—5–flowered, on long peduncle, flower oriented horizontally, bracteate, short–hairy; peduncle with pulvinus to 2 mm long, above pulvinus straight, to 90 × 1 mm, green, strigose and short–strigose with upward–pointing hairs, when first developing curved before straightening; bractlets subtending each pedicel 2, in series opposite decussate, appearing congested at top of peduncle, narrowly lanceolate or narrowly oblanceolate to lanceolate–linear, 1.5—5.2 × 0.4—0.7 mm decreasing upward, green, short–hairy, at least the largest 2 at top of peduncle persistent, from cyme secondary axis having peduncle below opposite decussate bractlets, those bractlets erect; pedicel 10—13 mm long.
Flower bisexual, radial, 7—13.5 mm across; sepals 5(—6), overlapping at base, free but appearing fused at base (= receptacle), ascending at anthesis and in fruit, ± erect, lanceolate to oblong or elliptic, 4.5—5.4 × 1.3—2 mm, green, obtuse to slightly notched at tip, lacking a tuft of hairs at tip, inconspicuously (3)5–veined at base, short–strigose on lower (outer) surface; petals 5(—7), not obviously fused, 7.2—11.5 mm long; tube to 2 mm long, with 5(—7) tooothlike attachments to receptacle (i.e, deltate openings), lacking a bulge above each tooth, colorless and greenish at base to light yellow approaching lobes; lobes spreading, fan–shaped, 5.5—9.5 × 2.5—4.5 mm, bright yellow to vivid yellow, with (2—)3—7 red streaks on lower lobe between nectar lines, nectar lines ca. 9 more visible on lower surface and faint in small flowers; stamens 10(—15) in 1 set fused into column surrounding pistil; tube membranous, 1.5—2 mm long, white; filaments dimorphic, alternating long and shoot, the longer ones opposite openings at base of corolla, 1—1.3 mm (short filaments) and 1.8—2.2 mm, white, flattened on inner surface; anthers dorsifixed, dithecal, 0.4—0.5 mm long, vivid yellow, longitudinally dehiscent; pollen yellow; nectaries 5(—7), bumps at base of staminal tube below each short filament, producing nectar to form a drop of nectar, potentially pooling between sepals and petals; pistil 1 = the longest stamens, 3.5—4.5 mm long; ovary superior, columnar with 5(—6) ribs, green, ribs slightly bulging from ovules, the basal portion initially glabrous and above midpoint white–pubescent, 5(—6)–chambered, each chamber with 10—16 ovules attached to center; styles = chambers, erect, ca. 1 mm long, green with white hairs, short 2–lobed at stigmatic tip, lobes 0.3—0.4 mm long, wet.
Fruit capsule, loculicidal, dehiscent by 5 valves, erect, columnar and strongly 5–angled, < 15—26 × 3.5—4 mm, short–strigose with downward–pointing hairs with pilose hairs along rib edges, sometimes bulging at seeds, chambers short–pilose.
Seed with aril, discoid–ovoid (excluding aril) 1.1—1.3 × 0.9—1 mm, compressed, rounded to obtuse at tips, transversely ridged, often with bumps along ridges, surfaces minutely papillate; before drying aril covering seed, fleshy, broadly ellipsoid, 1.3—1.4 mm long, milky–translucent, smooth; sepals ascending–spreading.
A. C. Gibson