Trifolium howellii |
Trifolium obtusiflorum |
|
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canyon clover, Howell's clover |
clammy clover, creek clover |
|
Habit | Herbs perennial, 30–100 cm, glabrous. | Herbs annual, 2–100 cm, resinous stipitate-glandular. |
Stems | erect, fistulose, unbranched or branched distally. |
erect or ascending, branched. |
Leaves | 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. |
palmate; stipules ovate, 1–1.5 cm, sheathing, margins deeply lacerate, apex acuminate; petiole 1.5–10 cm; petiolules to 0.5 mm; leaflets 3, blades elliptic, lanceolate, oblanceolate, rhombic, or obovate, 1.5–4 × 0.3–1.7 cm, base cuneate, veins thickened, margins coarsely spinulose-serrate, apex acute, mucronate, surfaces glandular. |
Inflorescences | 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. |
axillary or terminal, 10–50-flowered, globose or ovoid, 1–3.5 × 1–3 cm; involucres flattened or bowl-shaped, 3–8 mm, when folded, not hiding flowers except proximally, incised 1/4–1/3 their length. |
Peduncles | 3–11 cm. |
3–15 cm, glandular. |
Pedicels | strongly reflexed in fruit, 1 mm; bracteoles minute, blunt or acute, membranous. |
erect, 1 mm; bracteoles absent. |
Flowers | 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. |
13–20 mm; calyx tubular-campanulate, slit between adaxial lobes, 10–13 mm, glandular, veins 20+, tube 5–7 mm, lobes unequal, narrowly triangular or lanceolate-subulate, usually entire, rarely 3-fid or shouldered below apex, orifice open; corolla white or pale pinkish with dark purple spot, 10–18 mm, banner broadly elliptic, 10–18 × 2–4 mm, apex blunt. |
Legumes | oblong or clavate, 4–5 mm. |
obovoid, 3.5–4 mm. |
Seeds | 1–3, reddish black or brown, angular, mitten-shaped, 2.5 mm, smooth or slightly roughened, dull. |
1 or 2, brown, mottled, ellipsoid or mitten-shaped, 2.5 mm, smooth. |
2n | = 16. |
|
Trifolium howellii |
Trifolium obtusiflorum |
|
Phenology | Flowering Jun–Jul. | Flowering Apr–Jul. |
Habitat | Wet stream banks, wet meadows, flood plains, shady woodlands, springs, thickets. | Moist swales, creek bottoms. |
Elevation | 800–2000 m. (2600–6600 ft.) | 0–1600 m. (0–5200 ft.) |
Distribution |
CA; OR
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CA; OR; Mexico (Baja California, Sinaloa)
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Discussion | 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.) |
Trifolium obtusiflorum is much less common than the similar T. willdenovii, occurring in moist areas in cismontane California and north into Oregon (W. L. Jepson [1923–1925]). It is easy to distinguish from T. willdenovii by its glandularity, which causes fresh specimens to be sticky to the touch. (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. majus, T. roscidum, T. tridentatum var. obtusiflorum | |
Name authority | S. Watson: Proc. Amer. Acad. Arts 23: 262. (1888) | Hooker: Bot. Beechey Voy., 331. (1838) |
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