Trifolium amoenum |
Trifolium nanum |
|
---|---|---|
showy Indian clover, two-fork clover |
dwarf clover |
|
Habit | Herbs annual, 45–65 cm, canescent. | Herbs perennial, 4–10 cm, glabrous. |
Stems | erect, branched from base and distally, or unbranched. |
cespitose, matted, acaulescent. |
Leaves | 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 ovate-lanceolate, 1–2 cm, margins entire, apex acuminate, sometimes forked; petiole 0.3–2.5 cm; petiolules to 0.2 mm; leaflets 3, blades oblanceolate or obovate, 0.3–1.2 × 0.1–0.5 cm, base cuneate, veins ± thickened, margins toothed, apex acute or acuminate, surfaces glabrous. |
Inflorescences | terminal or axillary, 30–50-flowered, bluntly conic, ellipsoid, globose, or subglobose, 1.5–3 × 1.5–2.5 cm; involucres absent. |
terminal or axillary, 1–4-flowered, umbellate, 1.5–2 × 0.5–1 cm, rachis not prolonged beyond flowers; involucres a narrow, membranous, dentate rim, 1 mm. |
Peduncles | 5–15 cm. |
0.5–3 cm. |
Pedicels | absent; bracteoles cuplike, to 0.5 mm. |
erect, 1 mm; bracteoles cuplike, membranous, 0.5–1 mm. |
Flowers | 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. |
15–20 mm; calyx campanulate, 4–7 mm, glabrous, veins 5–10, tube 3–4 mm, lobes equal, triangular-acuminate, orifice open; corolla purple or violet, 15–20 mm, banner oblong, 15–20 × 7–9 mm, apex rounded, slightly retuse. |
Legumes | obovoid, 4 mm. |
oblanceoloid, 9–11 mm. |
Seeds | 1, dark brown, ellipsoid, 2–3 mm, smooth. |
4–6, tan or brown, mitten-shaped, 2–2.2 mm, smooth, dull. |
2n | = 16. |
|
Trifolium amoenum |
Trifolium nanum |
|
Phenology | Flowering Apr–May. | Flowering Jun–Aug. |
Habitat | Grassy slopes, swales, clay soils. | Alpine slopes, tundra. |
Elevation | 0–100 m. (0–300 ft.) | 2600–4500 m. (8500–14800 ft.) |
Distribution |
CA
|
CO; MT; NM; UT; WY
|
Discussion | 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 nanum is abundant in alpine tundra areas from Montana through Wyoming and Utah into Colorado (where it is most common) and northern New Mexico; populations are morphologically variable with regard to leaf size and petiole length, and this variability appears to be related to water availability (J. M. Gillett 1965). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Greene: Fl. Francisc., 27. (1891) | Torrey: Ann. Lyceum Nat. Hist. New York 1: 35, plate 3, fig. 4. (1824) |
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