Trifolium striatum |
Trifolium attenuatum |
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knotted clover |
Rocky Mountain clover |
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Habit | Herbs usually annual, rarely biennial, 10–50 cm, villous. | Herbs perennial, 5–30 cm, pubescent. |
Stems | erect, ascending, or decumbent, branched from base. |
erect or ascending, cespitose, branched from base, numerous short stems. |
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 lanceolate, 1.8–2 cm, margins entire, apex acute-acuminate; petiole 2.5–10 cm; petiolules to 0.5 mm; leaflets 3, blades linear, lanceolate, or narrowly elliptic, 1.5–6 × 0.3–1 cm, base cuneate, veins moderately thickened, margins entire, apex acuminate or narrowly acute, surfaces glabrous or pubescent. |
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, 10–20+-flowered, globose, 2.3–3.5 × 2.5–4 cm; involucres formed of proximal bracteoles, bases sometimes connate. |
Peduncles | 0–1 cm. |
2–28 cm. |
Pedicels | absent; bracteoles absent. |
reflexed in fruit, 2–4 mm; bracteoles ovate, 2–4 mm, truncate or acuminate. |
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. |
15–22 mm; calyx campanulate, 8–15 mm, pubescent, veins 10, tube 2.5–7 mm, lobes unequal, subulate, orifice open; corolla red-purple, 16–20 mm, banner broadly oblong-elliptic, 16–20 × 6–7 mm, apex acute, apiculate. |
Legumes | ovoid, leathery distally, transversely dehiscent, 2–2.5 mm. |
oblong, 5–6 mm. |
Seeds | 1, tan or reddish brown, globose to ovoid, 1–1.5 mm, smooth, glossy. |
1–3, brown, ovoid-reniform, 2.5 mm, smooth. |
2n | = 14. |
= 16, 48. |
Trifolium striatum |
Trifolium attenuatum |
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Phenology | Flowering May–Aug. | Flowering Jun–Aug. |
Habitat | Waste places | Subalpine and alpine slopes, open montane forests. |
Elevation | 0–500 m. (0–1600 ft.) | 3000–3800 m. (9800–12500 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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CO; NM
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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 attenuatum ranges from Park County in Colorado southward through southern and southwestern Colorado to northern and central New Mexico. J. M. Gillett (1965) found both diploid and hexaploid populations of Trifolium attenuatum but was unable to find morphological distinctions between diploid and hexaploid individuals. Using flavonoid chemotaxonomy, E. V. Parups et al. (1966) found close associations between T. attenuatum, T. brandegeei, and T. haydenii. Trifolium lilacinum Rydberg (1901), which pertains here, is a later homonym of T. lilacinum Greene (1896) and thus illegitimate. (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. bracteolatum, T. petraeum, T. stenolobum | |
Name authority | Linnaeus: Sp. Pl. 2: 770. (1753) | Greene: Pittonia 4: 137. (1900) |
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