Trifolium bifidum |
Trifolium columbinum |
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notch-leaf clover, Pinole clover, piñole clover |
olive clover |
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Habit | Herbs annual, 5–55 cm, sparsely pubescent or glabrous. | Herbs annual, 8–30 cm, canescent. |
Stems | erect, branched. |
erect, branched from base and distally, or unbranched. |
Leaves | palmate; stipules ovate to lanceolate, 0.8–1.5 cm, margins entire or slightly serrate, apex acicular; petiole 1–7 cm; petiolules to 0.5 mm; leaflets 3, blades narrowly obcordate, obovate, oblanceolate, or linear, 1–2.5 × 0.3–0.7 cm, base cuneate, veins moderately thickened, margins serrate distally or entire, apex rounded, truncate, shallowly to deeply retuse, or deeply 2-fid, surfaces glabrous or hairy abaxially along midvein. |
palmate; stipules ovate, 0.4–1.2 cm, margins entire, ciliate, apex often purple, acuminate, setaceous; petiole 0.5–8 cm; petiolules 0.5–1 mm; leaflets 3, blades obovate or elliptic, 0.5–3 × 0.3–1.2 cm, base cuneate, veins obscure or slightly thickened, margins dentate, apex rounded or emarginate, surfaces pilose. |
Inflorescences | axillary or terminal, 5–30-flowered, globose to subglobose, 0.8–1.5 × 0.8–1.5 cm, rachis prolonged beyond flowers; involucres a very narrow rim, to 0.5 mm. |
terminal or axillary, 25–50-flowered, ovoid-ellipsoid, 1–2.5 × 1.2–2.5 cm; involucres absent. |
Peduncles | 3–8 cm. |
3–11 cm. |
Pedicels | reflexed in fruit, 1–3 mm; bracteoles broadly triangular, membranous, to 0.5 mm. |
absent; bracteoles cuplike, to 0.5 mm. |
Flowers | 6–8 mm; calyx campanulate, 3–3.6 mm, slightly hairy or glabrous, veins 10, tube 1–1.5 mm, lobes unequal, subulate, margins green or purple, orifice open; corolla pink or purple, 5–7 mm, banner elliptic to oblong, 5–7 × 3–4 mm, apex rounded, apiculate. |
6–10 mm; calyx tubular, 8–14 mm, densely pubescent, veins 20–30, tube 1–2 mm, lobes nearly equal, appearing rigidly erect, linear-setaceous, plumose, sinuses acute, orifice open; corolla sometimes absent, red-violet, often with white tips, 4–6 mm, banner ovate-oblong, 7–8 × 2–3 mm, apex broadly rounded, apiculate. |
Legumes | stipitate, obovoid, 3–4 mm. |
obovoid, 3–3.5 mm. |
Seeds | 1 or 2, brown, mottled, oblong, 2–3 mm, smooth. |
1, yellow-brown, ellipsoid, 2–2.5 mm, smooth. |
2n | = 16. |
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Trifolium bifidum |
Trifolium columbinum |
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Phenology | Flowering Apr–Jun. | Flowering Apr–May. |
Habitat | Open woodlands, fields, roadsides, slopes, stream margins, meadows. | Grassy slopes, meadows, heavy adobe/clay soils, oak woodland foothills. |
Elevation | 0–1200 m. (0–3900 ft.) | 0–1400 m. (0–4600 ft.) |
Distribution |
CA; OR; WA; BC; Mexico (Baja California)
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CA |
Discussion | Trifolium bifidum ranges from Baja California, Mexico, northward through California to scattered sites in Oregon, Washington, and British Columbia. Recent re-evaluation of Trifolium bifidum and related species showed complete overlap in characters for the two varieties that have been recognized previously, with no clear distinctions between them (L. Rogers, pers. comm.). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
D. Isely (1998) stated that Central Valley populations of Trifolium columbinum appeared to be extinct and populations outside that region (and here recognized as the same taxon) were similar in calyx and corolla proportions. It is rather widespread in California, ranging from Humboldt County southward to Santa Barbara County, and eastward into counties ranging from Shasta southward to Inyo, Kern, and Placer counties. Trifolium albopurpureum var. olivaceum (Greene) Isely and T. columbinum var. olivaceum (Greene) Jepson are illegitimate names that pertain here (D. J. Keil 2019). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | Fabaceae > subfam. Faboideae > Trifolium | Fabaceae > subfam. Faboideae > Trifolium |
Sibling taxa | ||
Synonyms | T. bifidum var. decipiens, T. greenei, T. hallii | T. albopurpureum var. columbinum, T. columbinum var. argillorum, T. olivaceum, T. olivaceum var. columbinum, T. olivaceum var. griseum |
Name authority | A. Gray: Proc. Calif. Acad. Sci. 3: 102. (1864) | Greene: Pittonia 1: 4. (1887) |
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