Trifolium eriocephalum |
Trifolium cyathiferum |
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woolly-head clover |
bowl clover, cup clover |
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| Habit | Herbs perennial, 12–46 cm, sparsely hairy to densely villous, appressed-pubescent, or glabrate. | Herbs annual, 5–50 cm, glabrous. | ||||||||||||||||||||
| Stems | erect or decumbent, branched. |
erect, 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 to lanceolate, 0.6–1.2 cm, margins entire, toothed, or lacerate, apex acute or aristate; petiole 1–10 cm; petiolules to 0.5 mm; leaflets 3, blades obovate, elliptic, or oblanceolate, 0.5–2.5 × 0.3–1.5 cm, base cuneate, veins prominent, green, margins finely toothed, apex rounded, blunt, or retuse, surfaces 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, 1–35-flowered, subglobose or ovoid, 0.5–1.8 × 0.5–2 cm; involucres broadly bowl-shaped, 4–22 mm, shallowly incised, lobes 3–15, toothed, broad, acute. |
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| Peduncles | bent distally, proximal to flowers, 3–18 cm. |
1–8 cm. |
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| Pedicels | reflexed, to 0.3 mm; bracteoles absent. |
straight, 0.1–0.2 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. |
7–15 mm; calyx campanulate, inflated in fruit, 6–13 mm, glabrous, veins 13–20, tube 3–7 mm, lobes unequal, strongly oblique, broadly triangular, apex setaceous, adaxial unbranched, abaxial and lateral conspicuously 2- or 3-fid, segments glabrous, sometimes flattened, orifice open; corolla usually creamy white or rose to pink, sometimes whitish with pinkish tips, 6–13 mm, banner obovate or elliptic, proximally inflated in fruit, distally narrowed into twisted tip, 6–13 × 3–6 mm, apex rounded to broadly acute. |
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| Legumes | ovoid, 2–3.5 mm. |
ellipsoid, 2.5–3 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, yellow-brown, ovoid, 0.4–0.6 mm, smooth. |
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| 2n | = 16. |
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Trifolium eriocephalum |
Trifolium cyathiferum |
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| Phenology | Flowering Apr–Oct. | |||||||||||||||||||||
| Habitat | Wet meadows, roadsides, fields. | |||||||||||||||||||||
| Elevation | 0–2700 m. [0–8900 ft.] | |||||||||||||||||||||
| Distribution |
w United States
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AK; CA; ID; MT; NV; OR; WA; BC; YT [Introduced in Asia (China, Japan)]
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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 cyathiferum may be of hybrid origin; phylogenetic studies indicate it has the same trnL intron sequence as T. buckwestiorum, T. polyodon, and T. variegatum and nrDNA and combined analyses place it in a clade with other species (T. barbigerum, T. fucatum, T. jokerstii, and T. physanthum Hooker & Arnott) that have inflated fruiting corollas (N. W. Ellison et al. 2006). The single record of Trifolium cyathiferum labeled as from Utah is likely mislabeled (S. L. Welsh et al. 2008). Populations in Yukon may be introductions. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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| Key |
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| Name authority | Nuttall in J. Torrey and A. Gray: Fl. N. Amer. 1: 313. (1838) | Lindley: Bot. Reg. 13: sub plate 1070. (1827) | ||||||||||||||||||||
| Source | FNA vol. 11. | FNA vol. 11. | ||||||||||||||||||||
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