Oxalis pes-caprae |
Oxalis illinoensis |
|
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African wood-sorrel, Bermuda buttercup, soursob |
Illinois wood-sorrel |
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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, caulescent, rhizomes present, with horizontal, white, fusiform tubers or tuberlike thickenings, stolons absent, bulbs absent. |
Aerial stems | 1(–3) from base, erect, 15–40 cm, herbaceous, glabrate to sparsely to densely villous, hairs ± straight, spreading, septate and nonseptate. |
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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. |
cauline; stipules rudimentary; petiole 4–7.5 cm, hairs septate and nonseptate; leaflets 3, green, obcordate, (12–)20–30(–35) mm, lobed 1/5 length, lobes apically truncate, margins green, ciliate, surfaces glabrous, oxalate deposits absent. |
Inflorescences | umbelliform cymes, 2–12(–20)-flowered; scapes often becoming fistulose proximally, 15–30 cm, sparsely villous to pilose. |
regular or irregular cymes, 1–3(–6)-flowered; peduncles 3–10 cm. |
Flowers | tristylous in diploids and tetraploids, consistently short-styled in pentaploids; sepal apices with 2 orange tubercles; petals deep golden yellow, 15–20 mm. |
tristylous, mostly at level of leaves; sepal apices without tubercles; petals yellow, with prominent red lines proximally, 12–18 mm. |
Capsules | not seen. |
oblong-ovoid, 7–10 mm, sparsely puberulent to villous. |
Seeds | brown, transverse ridges brown. |
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2n | = 14, 28, 35. |
|
Oxalis pes-caprae |
Oxalis illinoensis |
|
Phenology | Flowering Nov–Apr. | Flowering Apr–Sep. |
Habitat | Disturbed areas, orchards, fields, grasslands, oak woodlands, coastal sage, dunes. | Slopes, bluffs, ravines, flood plains, mesic forests, sometimes forming dominant ground cover, commonly on limestone, shale, or calcareous loess. |
Elevation | 10–500 m. (0–1600 ft.) | 200–500 m. (700–1600 ft.) |
Distribution |
AZ; CA; s Africa [Introduced in North America; introduced also in West Indies, Bermuda, South America, Europe, Asia (China, Iran, Turkey), n Africa, Australia]
|
IL; IN; KY; TN |
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.) |
Differences between Oxalis illinoensis and O. grandis are subtle, but they appear to be correlated with geography. Oxalis illinoensis occupies the western part of the range of O. grandis in the wide sense. The tuberous portions of the rhizomes of O. illinoensis are diagnostic, but they are commonly broken off during collection. M. E. Medley (1993) observed that the two taxa intergrade, and a hybrid population has been identified in Indiana (A. L. Heikens 2003). Oxalis illinoensis is listed as threatened in Illinois and rare in Indiana. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 146. | FNA vol. 12, p. 145. |
Parent taxa | Oxalidaceae > Oxalis | Oxalidaceae > Oxalis |
Sibling taxa | ||
Synonyms | O. cernua | |
Name authority | Linnaeus: Sp. Pl. 1: 434. (1753) | Schwegman: Phytologia 50: 467. (1982) |
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