Trifolium eriocephalum |
Trifolium obtusiflorum |
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woolly-head clover |
clammy clover, creek clover |
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Habit | Herbs perennial, 12–46 cm, sparsely hairy to densely villous, appressed-pubescent, or glabrate. | Herbs annual, 2–100 cm, resinous stipitate-glandular. | ||||||||||||||||||||
Stems | erect or decumbent, branched. |
erect or ascending, branched. |
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Leaves | palmate; stipules lanceolate or ovate, 1–5 cm, margins entire or denticulate, apex acuminate or acute; petiole 1–15 cm; petiolules 1 mm; leaflets 3, blades linear, linear-elliptic, elliptic, lanceolate, lanceolate-oblong, or obovate, 1–5 × 0.4–1.2 cm, base cuneate, veins fine or ± thickened, margins denticulate or serrulate, apex acuminate or acute, surfaces appressed-pubescent abaxially, glabrous, densely villous, or sparsely or densely pilose adaxially. |
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. |
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Inflorescences | terminal or axillary, 25–70-flowered, inverted or horizontal, ellipsoid or globose to subglobose, 2–3 × 1–3 cm, rachis prolonged beyond flowers; 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. |
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Peduncles | bent distally, proximal to flowers, 3–18 cm. |
3–15 cm, glandular. |
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Pedicels | reflexed, to 0.3 mm; bracteoles absent. |
erect, 1 mm; bracteoles absent. |
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Flowers | 9–18 mm; calyx campanulate, curved in fruit, 4–11 mm, villous, veins 10, tube 1.5–2.5 mm, lobes unequal, 2–3 times tube, subulate, often strongly curved and twisted, plumose, orifice open; corolla white, cream, or purple, 8–16 mm, banner oblanceolate, 8–16 × 3–5 mm, apex rounded or retuse, recurved; ovaries pubescent distally. |
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. |
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Legumes | ovoid, 2–3.5 mm. |
obovoid, 3.5–4 mm. |
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Seeds | (1 or)2–4, yellow-brown to brown, mitten-shaped or subglobose, 1.2–2 mm, smooth. |
1 or 2, brown, mottled, ellipsoid or mitten-shaped, 2.5 mm, smooth. |
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2n | = 16. |
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Trifolium eriocephalum |
Trifolium obtusiflorum |
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Phenology | Flowering Apr–Jul. | |||||||||||||||||||||
Habitat | Moist swales, creek bottoms. | |||||||||||||||||||||
Elevation | 0–1600 m. [0–5200 ft.] | |||||||||||||||||||||
Distribution |
w United States
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CA; OR; Mexico (Baja California, Sinaloa)
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Discussion | Subspecies 6 (6 in the flora). Trifolium eriocephalum was revised by J. M. Gillett (1971). The subspecies exhibit unusually complex distributional patterns, and overlapping morphological features sometimes make identifications problematic (M. Zohary and D. Heller 1984). (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.) |
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Key |
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Source | FNA vol. 11. | FNA vol. 11. | ||||||||||||||||||||
Parent taxa | ||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||
Subordinate taxa | ||||||||||||||||||||||
Synonyms | T. majus, T. roscidum, T. tridentatum var. obtusiflorum | |||||||||||||||||||||
Name authority | Nuttall in J. Torrey and A. Gray: Fl. N. Amer. 1: 313. (1838) | Hooker: Bot. Beechey Voy., 331. (1838) | ||||||||||||||||||||
Web links |