Trifolium striatum |
Trifolium cyathiferum |
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knotted clover |
bowl clover, cup clover |
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Habit | Herbs usually annual, rarely biennial, 10–50 cm, villous. | Herbs annual, 5–50 cm, glabrous. |
Stems | erect, ascending, or decumbent, branched from base. |
erect, branched. |
Leaves | palmate; stipules lanceolate-ovate, 0.9–1.1 cm, margins entire, apex acute-acuminate, setaceous, ciliate; petiole 0.5–5 cm; petiolules 0.5 mm; leaflets 3, blades obovate to oblong, 0.9–1.6 × 0.4–1 cm, base cuneate, veins fine, margins denticulate, apex obtuse, obcordate, or emarginate, surfaces hairy. |
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. |
Inflorescences | axillary or terminal, solitary or paired, 20–60-flowered, ovoid or oblong, 0.8–1.6 × 0.6–1 cm; 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. |
Peduncles | 0–1 cm. |
1–8 cm. |
Pedicels | absent; bracteoles absent. |
straight, 0.1–0.2 mm; bracteoles absent. |
Flowers | 5–7 mm; calyx ellipsoid to urceolate, 3–4 mm, hairy, veins 10, tube 2–3 mm, lobes erect or spreading, unequal, abaxial longest and equal to tube, subulate, orifice open; corolla pink, 25–35 mm, banner oblong, 2.5–3.5 × 1.5–2 mm, apex retuse. |
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. |
Legumes | ovoid, leathery distally, transversely dehiscent, 2–2.5 mm. |
ellipsoid, 2.5–3 mm. |
Seeds | 1, tan or reddish brown, globose to ovoid, 1–1.5 mm, smooth, glossy. |
1 or 2, yellow-brown, ovoid, 0.4–0.6 mm, smooth. |
2n | = 14. |
= 16. |
Trifolium striatum |
Trifolium cyathiferum |
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Phenology | Flowering May–Aug. | Flowering Apr–Oct. |
Habitat | Waste places | Wet meadows, roadsides, fields. |
Elevation | 0–500 m. (0–1600 ft.) | 0–2700 m. (0–8900 ft.) |
Distribution |
AL; AR; CA; GA; MA; MO; NC; NJ; NY; OK; OR; PA; SC; VA; VT; WA; BC; Europe; w Asia; nw Africa [Introduced also in s South America (Chile), Pacific Islands (New Zealand), Australia]
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AK; CA; ID; MT; NV; OR; WA; BC; YT [Introduced in Asia (China, Japan)]
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Discussion | Trifolium striatum has been recorded as an occasional weed in the flora area, having been first collected on ballast in New Jersey in 1880. It is found sporadically as a weed of disturbed habitats and appears to be spreading rapidly. It has been called Pitts’s clover in the southern United States because it was discovered by J. D. Pitts in a field of crimson clover as a weed and he experimented with it as a forage plant (G. L. Fuller and B. H. Hendrickson 1928). (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.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | Fabaceae > subfam. Faboideae > Trifolium | Fabaceae > subfam. Faboideae > Trifolium |
Sibling taxa | ||
Name authority | Linnaeus: Sp. Pl. 2: 770. (1753) | Lindley: Bot. Reg. 13: sub plate 1070. (1827) |
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