Trifolium eriocephalum |
Trifolium microdon |
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woolly-head clover |
thimble clover, Valparaiso clover |
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Habit | Herbs perennial, 12–46 cm, sparsely hairy to densely villous, appressed-pubescent, or glabrate. | Herbs annual, 6–35 cm, villous or glabrous. | ||||||||||||||||||||
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 obliquely ovate, 0.4–1.2 cm, margins entire, toothed, or lacerate, apex acuminate; petiole 1–8 cm; petiolules 0.5 mm; leaflets 3, blades obovate or obcordate, 0.4–1.4 × 0.3–1.2 cm, base cuneate, veins fine, thickened distally, margins serrate, apex rounded or emarginate, surfaces villous or glabrous. |
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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, 10–17-flowered, subglobose, 0.8–1.7 × 0.5–1.5 cm; involucres cup-shaped, 0.5–1.5 cm, glabrous or sparsely hairy, lobes 8–12, ovate, conspicuously sharply toothed. |
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Peduncles | bent distally, proximal to flowers, 3–18 cm. |
1.5–7.4 cm. |
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Pedicels | reflexed, to 0.3 mm; bracteoles absent. |
absent; 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. |
6–7 mm; calyx tubular-campanulate, 3–4 mm, glabrous, veins 10, tube 2.5–3.5 mm, lobes ± equal, triangular, not or minutely aristate, conspicuously toothed, margins membranous, orifice open; corolla pale pink or white, 6–9 mm, banner oblong, 6–9 × 2–3 mm, apex narrowly rounded or emarginate-mucronate. |
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Legumes | ovoid, 2–3.5 mm. |
ovoid, 2–3 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, greenish, sometimes mottled, oblong, 1.5–2 mm, smooth. |
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2n | = 16. |
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Trifolium eriocephalum |
Trifolium microdon |
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Phenology | Flowering Apr–Jul. | |||||||||||||||||||||
Habitat | Meadows, roadsides, dry slopes, fields, open oak or pine forests. | |||||||||||||||||||||
Elevation | 0–1500 m. [0–4900 ft.] | |||||||||||||||||||||
Distribution |
w United States
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CA; ID; OR; WA; BC; Mexico (Baja California); South America (Chile)
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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 microdon is one of several clovers that have an apparently natural disjunct distribution between the western coast of South America (Chile) and western North America. Others include T. depauperatum var. depauperatum and T. macraei. In herbarium specimens of Trifolium microdon, the folded involucre hides, or nearly hides, the calyces, whereas in herbarium specimens of similar T. microcephalum, the calyces are still visible. (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 | ||||||||||||||||||||||
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Synonyms | T. microdon var. pilosum | |||||||||||||||||||||
Name authority | Nuttall in J. Torrey and A. Gray: Fl. N. Amer. 1: 313. (1838) | Hooker & Arnott: Bot. Misc. 3: 180. (1833) | ||||||||||||||||||||
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