Trifolium siskiyouense |
Trifolium buckwestiorum |
|
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Siskiyou clover |
Santa Cruz clover |
|
Habit | Herbs perennial, 20–50 cm, glabrous; rhizomes elongate, slender, roots tuberous. | Herbs annual, 5–40 cm, glabrous. |
Stems | erect, sparsely branched. |
decumbent to ascending or erect, slightly branched. |
Leaves | 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 whitish with prominent green veins, ovate, 0.3–0.5 cm, margins lacerate, apex acute to acuminate; petiole 1–2.4 cm; petiolules to 0.5 mm; leaflets 3, blades obovate to elliptic, 0.6–1.5 × 0.3–0.8 cm, base cuneate, veins ± thickened distally, margins denticulate, sometimes entire proximally, apex rounded, acute, or retuse, surfaces glabrous. |
Inflorescences | 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. |
terminal or axillary, 15–20-flowered (early inflorescences hidden in stipules, subsessile, 2–5-flowered, flowers cleistogamous), subglobose, 0.5–0.8 × 0.6–0.8 cm; involucres flattened or shallowly bowl-shaped, 6–8 mm, when folded, nearly hiding calyces, glabrous or sparsely hairy, lobes 4 or 5, ± parallel-sided, 3 or 4-toothed. |
Peduncles | 2.8–3.4 cm. |
1–3.5 cm. |
Pedicels | straight, 0.5–0.8 mm; bracteoles linear, 1–2 mm. |
straight, to 0.5 mm; bracteoles absent. |
Flowers | 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. |
7–8 mm; calyx tubular, 4–5 mm, glabrous, veins 10, tube 2–2.5 mm, lobes subequal, triangular, margins conspicuously 2 or 3-toothed, apex aristate, orifice open; corolla pale pink or white, 6–7 mm, banner oblong, 5–7 × 1 mm, apex emarginate or erose. |
Legumes | oblong, 2–4 mm. |
ovoid, 2.5 mm. |
Seeds | 2–4, brown, subglobose or mitten-shaped, 1.5 mm, smooth. |
1, dark brown, slightly mottled, ovoid, 2 mm, smooth. |
Trifolium siskiyouense |
Trifolium buckwestiorum |
|
Phenology | Flowering Jun–Jul. | Flowering May–Jun. |
Habitat | Wet meadows, grassy hillsides. | Meadows, roadsides, grassy hillsides. |
Elevation | 1000–1500 m. (3300–4900 ft.) | 0–300 m. (0–1000 ft.) |
Distribution |
CA; OR |
CA |
Discussion | 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 buckwestiorum, which ranges from Mendocino to Monterey counties, is unique among clovers in North America because of its aboveground cleistogamous, axillary flowers. The only other clover in North America that produces cleistogamous flowers is T. amphianthum, which produces its cleistogamous flowers at ground level and then pushes them into the substrate. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | T. wormskioldii var. siskiyouense | |
Name authority | J. M. Gillett: Canad. J. Bot. 58: 1441. (1980) | Isely: Madroño 39: 90, fig. 2. (1992) |
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