Trifolium vesiculosum |
Trifolium howellii |
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arrow-leaf clover |
canyon clover, Howell's clover |
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Habit | Herbs annual, 15–70 cm, glabrous. | Herbs perennial, 30–100 cm, glabrous. |
Stems | erect or ascending, branched. |
erect, fistulose, unbranched or branched distally. |
Leaves | palmate; stipules linear-lanceolate, 1–3.5 cm, margins entire, apex subulate or setaceous; petiole 0.5–10 cm; petiolules 1 mm; leaflet 3, blades obovate to oblong, elliptic or lanceolate, 0.5–4 × 0.5–1.5 cm, base cuneate, veins prominent, thickened, margins spinulose-denticulate, apex apiculate, surfaces glabrous. |
palmate; stipules ovate, 1.5–4.5 cm, margins usually entire, sometimes lobed, apex acuminate; petiole 0.5–20 cm; petiolules 1–1.5 mm; leaflets 3, blades ovate, elliptic, or rhombic, 3.5–9.5 × 2.3–5 cm, base cuneate, veins obscure, margins ± serrate, apex acute, rounded, or obtuse, surfaces glabrous. |
Inflorescences | terminal or axillary, 50–100+-flowered, globose, ovoid, or oblong, 3–6 × 2–3.5 cm; involucres absent. |
terminal or axillary, 20–70-flowered, globose or ellipsoid, 2.5–4 × 2–2.5 cm, rachis prolonged beyond flowers, undivided or forked, often bearing sterile flower buds distally; involucres absent. |
Peduncles | 1–12 cm. |
3–11 cm. |
Pedicels | absent; bracteoles lanceolate, 6–7 mm, acuminate. |
strongly reflexed in fruit, 1 mm; bracteoles minute, blunt or acute, membranous. |
Flowers | 12–16 mm; calyx urceolate, not bilabiate, inflated in fruit, 6–10 mm, glabrous, veins 20–36, connected by transverse veins in fruit, tube 3–5 mm, lobes reflexed, subequal, subulate, as long as tube, orifice constricted; corolla white becoming pink, 12–15 mm, banner ovate, broadly clawed, striate, 12–15 × 2–4 mm, apex acute-acuminate. |
10–14 mm; calyx campanulate, gibbous, 4–5.5 mm, glabrous, veins 10, tube 2–2.5 mm, lobes subequal, linear-lanceolate, orifice open; corolla white, lemon yellow, or greenish yellow, 11–12 mm, banner elliptic-oblong, 11–12 × 4–5 mm, apex obtuse. |
Legumes | ellipsoid, 2.5–2.5 mm, shorter than calyx. |
oblong or clavate, 4–5 mm. |
Seeds | 2 or 3, brown, ovoid, 1–1.5 mm, roughened. |
1–3, reddish black or brown, angular, mitten-shaped, 2.5 mm, smooth or slightly roughened, dull. |
2n | = 16. |
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Trifolium vesiculosum |
Trifolium howellii |
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Phenology | Flowering Apr–Jul. | Flowering Jun–Jul. |
Habitat | Fields, roadsides, forest openings. | Wet stream banks, wet meadows, flood plains, shady woodlands, springs, thickets. |
Elevation | 0–1000 m. (0–3300 ft.) | 800–2000 m. (2600–6600 ft.) |
Distribution |
AL; AR; CA; FL; GA; LA; MA; MO; MS; OK; OR; SC; TX; VA; WA; s Europe; e Europe; w Asia [Introduced in North America]
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CA; OR
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Discussion | Trifolium vesiculosum was first introduced into cultivation in the United States in 1963 and is grown in southern and western states (J. D. Miller and H. D. Wells 1985). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Trifolium howellii is known from Del Norte, Humboldt, Siskiyou, and Trinity counties in California, and Clackamas, Douglas, Jackson, Josephine, Klamath, Lane, and Linn counties in Oregon (J. M. Gillett 1972). It has some of the largest leaves of any species of Trifolium in North America. (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 | ||
Name authority | Savi: Fl. Pis. 2: 165. (1798) — (as vessiculosum) | S. Watson: Proc. Amer. Acad. Arts 23: 262. (1888) |
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