Trifolium siskiyouense
Trifolium oliganthum
Siskiyou clover
few-flower clover, few-flowerered clover
erect, sparsely branched.
erect, dichotomously branched.
palmate;
stipules lanceolate, 0.8–1.5 cm, margins entire or slightly lacerate, apex acuminate;
petiole 1.6–2.4 cm;
petiolules 0.5 mm;
leaflets 3, blades obovate, oblanceolate, or elliptic, 0.8–3 × 0.5–0.7 cm, base cuneate, veins fine or thickened distally, margins finely serrulate, apex acute, mucronate, or retuse, surfaces glabrous.
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.
usually terminal, sometimes axillary, 30–50-flowered, subglobose, 1.2–1.8 × 1.5–2 cm;
involucres shallowly bowl-shaped, 18–22 mm, deeply incised, lobes slender, irregular or bifurcate.
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.
2.8–3.4 cm.
2.5–7.5 cm.
straight, 0.5–0.8 mm;
bracteoles linear, 1–2 mm.
erect, 0.5–2 mm;
bracteoles absent.
10–13 mm;
calyx tubular, 0.5–0.6 mm, glabrous, veins 10, tube 2 mm, lobes ± equal, 3–4 mm, orifice open;
corolla white to purple, 9–12 mm, banner oblong, 7–12 × 2–3 mm, apex retuse.
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.
oblong, 2–4 mm.
sessile, oblong, 2.1–3.2 mm.
2–4, brown, subglobose or mitten-shaped, 1.5 mm, smooth.
1 or 2 (or 3), reddish brown, mottled, lenticular or reniform, 1.2–1.3 mm, smooth.
= 16.
Trifolium siskiyouense
Trifolium oliganthum
Trifolium siskiyouense is known from Shasta and Siskiyou counties, California, and Douglas, Jackson, and Josephine counties, Oregon. It is difficult to distinguish from T. wormskioldii without underground parts showing the tubers, but can be separated from the latter by deeply cut involucral segments, long-lobed, slender calyces, and the combination of long wing petals and short keel petals (J. M. Gillett 1980).
(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
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
