Trifolium amoenum
Trifolium oliganthum
showy Indian clover, two-fork clover
few-flower clover, few-flowerered clover
erect, branched from base and distally, or unbranched.
erect, dichotomously branched.
palmate;
stipules ovate-oblong, 0.5–1.8 cm, margins entire, toothed, or irregularly lobed, apex acuminate;
petiole 0.5–10 cm;
petiolules to 1 mm;
leaflets 3, blades broadly obovate or elliptic, 1.7–3.3 × 1.1–2 cm, base cuneate, veins fine, margins entire or denticulate, apex rounded, obtuse, or retuse, surfaces pilose, abaxial less so.
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.
terminal or axillary, 30–50-flowered, bluntly conic, ellipsoid, globose, or subglobose, 1.5–3 × 1.5–2.5 cm;
involucres absent.
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.
5–15 cm.
2.5–7.5 cm.
absent;
bracteoles cuplike, to 0.5 mm.
erect, 0.5–2 mm;
bracteoles absent.
13–16 mm;
calyx tubular, 9–12 mm, pubescent, veins 20–30, tube 3 mm, lobes nearly equal, appearing rigidly erect, linear-setaceous, plumose, sinuses acute, orifice open;
corolla white to pink with purple tips, 12–16 mm, banner ovate-oblong, 12–15 × 4 mm, apex broadly rounded, emarginate.
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.
obovoid, 4 mm.
sessile, oblong, 2.1–3.2 mm.
1, dark brown, ellipsoid, 2–3 mm, smooth.
1 or 2 (or 3), reddish brown, mottled, lenticular or reniform, 1.2–1.3 mm, smooth.
= 16.
Trifolium amoenum
Trifolium oliganthum
Trifolium amoenum was considered extinct (J. P. Smith Jr. 1984) but was rediscovered in 1993 (P. G. Connors 1994). Specimens of T. amoenum are known from Marin, Napa, San Mateo, Solano, and Sonoma counties; it appears to be extant in only single populations in each of Marin and Solano counties. Allozyme studies of the two known populations revealed fixed genetic differences between them (E. E. Knapp and Connors 1999).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.)
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria, Turner Photog. 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
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- Encyclopedia of Life
- Wikipedia
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