Trifolium striatum |
Trifolium pratense |
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knotted clover |
red clover |
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Habit | Herbs usually annual, rarely biennial, 10–50 cm, villous. | Herbs perennial, 20–70 cm, pilose or glabrous. |
Stems | erect, ascending, or decumbent, branched from base. |
erect, ascending, or decumbent, 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 broadly triangular, 1–2 cm, margins entire, sometimes ciliate, apex mucronate or setaceous; petiole 1–9 cm; petiolules 1 mm; leaflets 3, blades elliptic to obovate, 1.5–5 × 0.7–1.5 cm, base cuneate, veins prominent, margins subentire, apex obtuse, acute, or retuse, surfaces appressed-pubescent. |
Inflorescences | axillary or terminal, solitary or paired, 20–60-flowered, ovoid or oblong, 0.8–1.6 × 0.6–1 cm; involucres absent. |
terminal, solitary or paired, 75–100+-flowered, globose or ovoid, 1.2–7.7 × 0.7–2.2 cm; involucres absent, involucrelike structures formed of stipules of distalmost leaves. |
Peduncles | 0–1 cm. |
± 0 cm, subtended by stipules of distal leaves. |
Pedicels | absent; bracteoles absent. |
straight, 0–1 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. |
15–18 mm; calyx tubular-campanulate, 8–11 mm, hairy, veins 10, tube 3–4 mm, lobes unequal, adaxial equaling tube, lateral and abaxial 2 times tube, orifice hairy, slightly closed; corolla usually rose-purple, rarely pink or white, 13–18 mm, banner elliptic-ovate, 10–13 × 3–5 mm, apex narrowly rounded. |
Legumes | ovoid, leathery distally, transversely dehiscent, 2–2.5 mm. |
oblong, leathery distally, transversely dehiscent, 3 mm. |
Seeds | 1, tan or reddish brown, globose to ovoid, 1–1.5 mm, smooth, glossy. |
1 or 2, yellow, yellow-brown, or purple, ovoid, 1.6–2 mm, smooth, dull. |
2n | = 14. |
= 14. |
Trifolium striatum |
Trifolium pratense |
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Phenology | Flowering May–Aug. | Flowering May–Sep. |
Habitat | Waste places | Fields, prairies, roadsides, disturbed areas. |
Elevation | 0–500 m. (0–1600 ft.) | 0–3100 m. (0–10200 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; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; NT; ON; PE; QC; SK; YT; SPM; Greenland; Eurasia [Introduced in North America; introduced also in s South America, s Africa, Pacific Islands (Hawaii, New Zealand), Australia]
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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 pratense is morphologically variable and numerous varieties have been recognized (M. Zohary and D. Heller 1984). Distinctions among these are slight and intergradation is common, perhaps due to the long-time cultivation of the species. In North America, the following varieties are sometimes recognized: var. pratense with stems decumbent to ascending, 20–40 cm, with dense, appressed, white hairs; var. sativum Schreber with stems mostly erect, 40–100 cm, sparsely hairy or glabrous; and var. americanum Harz with stems 30–100 cm, with dense, spreading hairs. (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. pensylvanicum | |
Name authority | Linnaeus: Sp. Pl. 2: 770. (1753) | Linnaeus: Sp. Pl. 2: 768. (1753) |
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