Trifolium campestre |
Trifolium microcephalum |
|
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field clover, hop clover, hop trefoil, low hop-clover, pinnate hop clover |
small-head clover |
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Habit | Herbs annual, 5–40 cm, slightly villous or glabrous. | Herbs annual, 3–55 cm, densely to sparsely pubescent. |
Stems | erect to ascending, branched. |
erect to ascending, branched. |
Leaves | pinnate; stipules ovate-lanceolate, 0.5–0.8 cm, margins entire, glandular, apex acuminate; petiole 0.3–2 cm; lateral leaflet petiolules 0.5–0.6 mm, terminal leaflet stalk 3–5 mm; leaflets 3, blades rhombic to obovate, 0.4–1.5 × 0.4–0.8 cm, base cuneate, lateral veins prominent, ± parallel, ascending, margins denticulate distally, apex truncate or retuse, surfaces strigose adaxially. |
palmate; stipules obliquely ovate, 0.4–1.2 cm, margins entire or slightly serrate, apex acuminate; petiole 1–5 cm; petiolules 0.5 mm; leaflets 3, blades oblanceolate, obovate, or obcordate, 0.4–1.7 × 0.3–1.1 cm, base cuneate, veins fine or slightly thickened, margins setose, often dentate distally, apex usually retuse, rarely rounded, surfaces villous. |
Inflorescences | axillary, 30–60-flowered, globose or broadly ovoid, 0.8–1.5 × 0.7–1 cm; involucres absent. |
axillary or terminal, 10–40-flowered, globose, 0.5–1.3 × 0.4–1.2 cm; involucres flattened or bowl-shaped, 0.4–1 cm, when folded, nearly completely hiding calyces, villous, incised 1/2 their length, lobes 5–12, lanceolate-ovate, entire or slightly toothed proximally, acuminate. |
Peduncles | 1.5–3.5 cm. |
1–8 cm. |
Pedicels | reflexed, 0.7–1.2 mm; bracteoles a fringe of red setae. |
absent; bracteoles absent. |
Flowers | 4.3–5 mm; calyx campanulate, strongly bilabiate, 1.3–1.5 mm, glabrous, veins 5, tube 0.3–0.6 mm, lobes unequal, adaxial deltate, very short, lateral and abaxial linear-subulate, each tipped with 1 or 2 stiff hairs, orifice open; corolla yellow becoming brown, 3.5–6 mm, ribbed, banner persistent, obovate, enveloping other petals, boat-shaped, 4.3–5 × 2.8–3.2 mm, apex broad, acute. |
4–6 mm; calyx campanulate-tubular, 3–5.5 mm, pubescent, veins 10, tube 1.8–2.5 mm, lobes ± equal, triangular-aristate, margins hyaline, wavy, orifice open; corolla white or pink to lavender, 4–6 mm, banner oblong, 3–6 × 1–2 mm, apex emarginate. |
Legumes | stipitate, oblong, 2–2.5 mm. |
broadly ellipsoid, 1.5–2 mm. |
Seeds | 1 or 2, yellow, ellipsoid, 1–1.5 mm, smooth, lustrous. |
1, yellow, reddish mottled, oblong, 1.5 mm, smooth. |
2n | = 14. |
= 16. |
Trifolium campestre |
Trifolium microcephalum |
|
Phenology | Flowering Jun–Aug. | Flowering Mar–Jul. |
Habitat | Roadsides, fields. | Meadows, roadsides, stream banks, forest clearings, grassy slopes. |
Elevation | 0–1700 m. (0–5600 ft.) | 0–2500 m. (0–8200 ft.) |
Distribution |
AK; AL; AR; AZ; CA; 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; NY; OH; OK; OR; PA; RI; SC; TN; TX; VA; VT; WA; WI; WV; WY; BC; NB; NF; NS; ON; PE; QC; SPM; Europe; w Asia; n Africa [Introduced in North America; introduced also in South America, e Asia (China), s Africa, Pacific Islands (Hawaii, New Zealand), Australia]
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AK; AZ; CA; ID; MT; NV; OR; WA; BC; Mexico (Baja California)
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Discussion | Trifolium filiforme Linnaeus and T. procumbens Linnaeus are rejected names that were used historically for T. campestre (J. E. Dandy 1958; N. J. Turland et al. 1996). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Trifolium microcephalum is common in much of its range in California and northward into Oregon, and is rare in much of the rest of its range. It is closely allied with the Chilean T. vernum Philippi (N. W. Ellison et al. 2006), which it resembles greatly, and from which it is distinguished by its shorter calyx lobes (M. Zohary and D. Heller 1984). (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 | Chrysaspis campestris | Lojaconoa microcephala, T. microcephalum var. bipedale, T. microcephalum var. lemmonii |
Name authority | Schreber in G. F. Hoffmann: Deutschl. Fl. 4: 16, plate 253. (1804) | Pursh: Fl. Amer. Sept. 2: 478. (1813) |
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