Trifolium howellii |
Trifolium sonorense |
|
---|---|---|
canyon clover, Howell's clover |
Sonoran clover |
|
Habit | Herbs perennial, 30–100 cm, glabrous. | Herbs perennial, 25–38+ cm, pubescent. |
Stems | erect, fistulose, unbranched or branched distally. |
prostrate, branched. |
Leaves | palmate; stipules ovate, 1.5–4.5 cm, margins usually entire, sometimes lobed, apex acuminate; petiole 0.5–20 cm; petiolules 1–1.5 mm; leaflets 3, blades ovate, elliptic, or rhombic, 3.5–9.5 × 2.3–5 cm, base cuneate, veins obscure, margins ± serrate, apex acute, rounded, or obtuse, surfaces glabrous. |
palmate; stipules narrowly triangular, 0.7–1.7 cm, margins entire or finely serrulate, apex usually acute or acuminate, sometimes 2-fid; petiole 0.3–5 cm; petiolules to 1 mm; leaflets 3, blades obovate to obcordate, 0.9–1.6 × 0.7–1.2 cm, base cuneate, veins moderately thickened, margins serrate to weakly so, apex rounded or emarginate, mucronulate, surfaces slightly hairy abaxially, glabrous adaxially. |
Inflorescences | terminal or axillary, 20–70-flowered, globose or ellipsoid, 2.5–4 × 2–2.5 cm, rachis prolonged beyond flowers, undivided or forked, often bearing sterile flower buds distally; involucres absent. |
axillary, 10–20-flowered, depressed-globose or globose, 0.8–1.6 × 0.9–1.6 cm, rachis prolonged beyond flowers; involucres a narrow rim, or slightly proximally connate bracteoles of proximal flowers, 0.1–0.5 mm. |
Peduncles | 3–11 cm. |
2.8–5 cm. |
Pedicels | strongly reflexed in fruit, 1 mm; bracteoles minute, blunt or acute, membranous. |
reflexed in fruit, 1–3 mm; bracteoles linear-triangular, 0.5 mm. |
Flowers | 10–14 mm; calyx campanulate, gibbous, 4–5.5 mm, glabrous, veins 10, tube 2–2.5 mm, lobes subequal, linear-lanceolate, orifice open; corolla white, lemon yellow, or greenish yellow, 11–12 mm, banner elliptic-oblong, 11–12 × 4–5 mm, apex obtuse. |
5.7–6.7 mm; calyx tubular, 3.3–6.5 mm, pubescent, veins 10, tube 0.8–1 mm, lobes subequal, narrowly triangular, orifice open; corolla white or pink, 5.3–6.5 mm, banner obovate, 5.3–6.5 × 2.8–3.8 mm, apex broadly rounded or broadly acute. |
Legumes | oblong or clavate, 4–5 mm. |
obovoid, 4.3–4.4 mm. |
Seeds | 1–3, reddish black or brown, angular, mitten-shaped, 2.5 mm, smooth or slightly roughened, dull. |
2, brownish orange or olive-brown, globose or broadly reniform, 1.2–1.7 mm, smooth. |
2n | = 16. |
|
Trifolium howellii |
Trifolium sonorense |
|
Phenology | Flowering Jun–Jul. | Flowering Aug–Oct. |
Habitat | Wet stream banks, wet meadows, flood plains, shady woodlands, springs, thickets. | Dry stream banks, grassy places. |
Elevation | 800–2000 m. (2600–6600 ft.) | 1500–1800 m. (4900–5900 ft.) |
Distribution |
CA; OR
|
AZ; Mexico (Chihuahua, Jalisco, Sinaloa, Sonora) |
Discussion | Trifolium howellii is known from Del Norte, Humboldt, Siskiyou, and Trinity counties in California, and Clackamas, Douglas, Jackson, Josephine, Klamath, Lane, and Linn counties in Oregon (J. M. Gillett 1972). It has some of the largest leaves of any species of Trifolium in North America. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Trifolium sonorense has long been equated with T. amabile Kunth, from which T. K. Ahlquist (2012) and also Ahlquist & M. A. Vincent have shown it to be distinct by longer sepal lobes (more than 3 mm), keel petal claws (more than 1.7 mm), and filament tubes (more than 3.6 mm). Trifolium sonorense is known from western Mexico and southernmost Arizona (Cochise County), largely in the Sonoran Desert region, and in mountainous Jalisco. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | Fabaceae > subfam. Faboideae > Trifolium | Fabaceae > subfam. Faboideae > Trifolium |
Sibling taxa | ||
Name authority | S. Watson: Proc. Amer. Acad. Arts 23: 262. (1888) | T. K. Ahlquist & Vincent: Phytoneuron 2018-1: 1, fig. 1. (2018) |
Web links |