Trifolium oliganthum |
Trifolium campestre |
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few-flower clover, few-flowerered clover |
field clover, hop clover, hop trefoil, low hop-clover, pinnate hop clover |
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Habit | Herbs annual, 10–50 cm, glabrous. | Herbs annual, 5–40 cm, slightly villous or glabrous. |
Stems | erect, dichotomously branched. |
erect to ascending, branched. |
Leaves | palmate; stipules lanceolate, 0.4–1.2 cm, margins lacerate, apex subulate; petiole 0.5–4 cm; petiolules to 0.5 mm; leaflets 3, blades linear, oblong, oblanceolate, or elliptic, 0.5–2.5 × 0.1–0.5 cm, base cuneate, veins fine or moderately thickened, margins entire, spinulose, or dentate, apex rounded or truncate, mucronate, surfaces glabrous. |
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. |
Inflorescences | axillary or terminal, 3–15-flowered, obconic, 0.3–1.2 × 0.3–0.8 cm; involucres flattened to bowl-shaped, 1–2 mm, when folded, not hiding flowers except proximally, incised 4/5–9/10 their length, lobes lanceolate-subulate. |
axillary, 30–60-flowered, globose or broadly ovoid, 0.8–1.5 × 0.7–1 cm; involucres absent. |
Peduncles | 2.5–7.5 cm. |
1.5–3.5 cm. |
Pedicels | erect, 0.5–2 mm; bracteoles absent. |
reflexed, 0.7–1.2 mm; bracteoles a fringe of red setae. |
Flowers | 11–16 mm; calyx campanulate, slit between adaxial lobes, 4–5 mm, glabrous, veins 10, tube 2.5–5.2 mm, lobes triangular-subulate, 3-fid or shouldered below apex, orifice open; corolla lavender with white tips, keel petals purple, 6–8 mm, banner narrowly ovate-oblong, 6–8 × 2 mm, apex narrowly rounded, erose. |
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. |
Legumes | sessile, oblong, 2.1–3.2 mm. |
stipitate, oblong, 2–2.5 mm. |
Seeds | 1 or 2 (or 3), reddish brown, mottled, lenticular or reniform, 1.2–1.3 mm, smooth. |
1 or 2, yellow, ellipsoid, 1–1.5 mm, smooth, lustrous. |
2n | = 16. |
= 14. |
Trifolium oliganthum |
Trifolium campestre |
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Phenology | Flowering Mar–Jul. | Flowering Jun–Aug. |
Habitat | Stream banks, grassy, rocky slopes, meadows, fields. | Roadsides, fields. |
Elevation | 0–1100 m. (0–3600 ft.) | 0–1700 m. (0–5600 ft.) |
Distribution |
CA; OR; WA; BC
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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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Discussion | Trifolium oliganthum is relatively common throughout much of its range in California; it is found in a few scattered sites northward into Oregon, Washington, and British Columbia. Even though it closely resembles T. variegatum, it is placed near T. bifidum in molecular studies (N. W. Ellison et al. 2006). Trifolium hexanthum Greene ex A. Heller, which pertains here, is not a validly published name. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | T. pauciflorum, T. filipes, T. oliganthum var. sonomense, T. triflorum | Chrysaspis campestris |
Name authority | Steudel: Nomencl. Bot. ed. 2, 2: 707. (1841) | Schreber in G. F. Hoffmann: Deutschl. Fl. 4: 16, plate 253. (1804) |
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