Flora of North America species comparison

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Oxalis pes-caprae

Oxalis trilliifolia

African wood-sorrel, Bermuda buttercup, soursob

great oxalis, great wood-sorrel, three leaf woodsorrel, trillium leaf oxalis, trillium-leaf wood-sorrel
Habit Herbs perennial, acaulous, rhizomes present vertical, white, rootlike, stolons absent, bulb usually solitary, sometimes with bulblets at base; bulb scales not observed. Herbs perennial, acaulous, rhizomes present, fleshy-thickened, densely scaly, stolons absent, bulbs absent.
Leaves

basal, rarely absent at flowering;

petiole 3–12 cm;

leaflets 3, green, rarely mottled with purplish red spots, angular-obcordate, (5–)7–20 mm, lobed 1/4–2/5 length, lobes apically convex, margins and abaxial surface villous, adaxial surface glabrous, oxalate deposits absent.

basal, clustered at rhizome tips;

petiole 15–30 cm;

leaflets 3, green, broadly obcordate, 20–40(–60) mm, lobed 1/6–1/4 length, lobes apically convex, surfaces sparsely villous, oxalate deposits absent.
Inflorescences

umbelliform cymes, 2–12(–20)-flowered;

scapes often becoming fistulose proximally, 15–30 cm, sparsely villous to pilose.

umbelliform cymes, 2–9(–15)-flowered;

scapes 15–25 cm, glabrous or sparsely villous.
Flowers

tristylous in diploids and tetraploids, consistently short-styled in pentaploids;

sepal apices with 2 orange tubercles;

petals deep golden yellow, 15–20 mm.

heterostylous;

sepal apices without tubercles;

petals white to pinkish, sometimes greenish proximally, without prominent veins, 8–14 mm.
Capsules

not seen.

narrowly fusiform, 15–25(–30) mm, glabrous.
2n

= 14, 28, 35.

Oxalis pes-caprae

Oxalis trilliifolia
Phenology Flowering Nov–Apr. Flowering May–Sep.
Habitat Disturbed areas, orchards, fields, grasslands, oak woodlands, coastal sage, dunes. Redwood, spruce-fir, Douglas fir, hemlock, hemlock-cedar, hemlock-alder woodlands, stream margins, swamps.
Elevation 10–500 m. (0–1600 ft.) 20–1800 m. (100–5900 ft.)
Distribution
from FNA
AZ; CA; s Africa [Introduced in North America; introduced also in West Indies, Bermuda, South America, Europe, Asia (China, Iran, Turkey), n Africa, Australia]
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; ID; OR; WA
[WildflowerSearch map]
[BONAP county map]
Discussion

Outside its native range, Oxalis pes-caprae is mostly represented by a sterile pentaploid morph, although tetraploids also are known. The occurrence of both pentaploid and tetraploid individuals in the exotic range may be the result of independent introductions (P. Michael 1964; R. Ornduff 1986). Fruit production has not been observed in North America, and the plants are assumed to be seed-sterile (Ornduff 1987). Bulbs of O. pes-caprae are rarely collected, as they detach easily from the vertical, rootlike stems. Each bulb may produce over 20, small, whitish bulblets each year. Bulblets may also be formed at the soil surface crown.

Oxalis pes-caprae was reported by J. K. Small (1933) to occur in waste places and cultivated grounds in northern Florida, but as noted by D. B. Ward (2004), no Florida specimens are known.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 12, p. 146. FNA vol. 12, p. 147.
Parent taxa Oxalidaceae > Oxalis Oxalidaceae > Oxalis
Sibling taxa
O. albicans, O. articulata, O. bowiei, O. brasiliensis, O. caerulea, O. californica, O. colorea, O. corniculata, O. debilis, O. decaphylla, O. dichondrifolia, O. dillenii, O. drummondii, O. florida, O. frutescens, O. grandis, O. hirta, O. hispidula, O. illinoensis, O. incarnata, O. intermedia, O. latifolia, O. laxa, O. macrantha, O. metcalfei, O. montana, O. oregana, O. pilosa, O. purpurea, O. stricta, O. suksdorfii, O. texana, O. triangularis, O. trilliifolia, O. violacea
O. albicans, O. articulata, O. bowiei, O. brasiliensis, O. caerulea, O. californica, O. colorea, O. corniculata, O. debilis, O. decaphylla, O. dichondrifolia, O. dillenii, O. drummondii, O. florida, O. frutescens, O. grandis, O. hirta, O. hispidula, O. illinoensis, O. incarnata, O. intermedia, O. latifolia, O. laxa, O. macrantha, O. metcalfei, O. montana, O. oregana, O. pes-caprae, O. pilosa, O. purpurea, O. stricta, O. suksdorfii, O. texana, O. triangularis, O. violacea
Synonyms O. cernua Hesperoxalis trilliifolia
Name authority Linnaeus: Sp. Pl. 1: 434. (1753) Hooker: Fl. Bor.-Amer. 1: 118. (1831) — (as trilliifolium)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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