Trifolium nanum |
Trifolium sonorense |
|
---|---|---|
dwarf clover |
Sonoran clover |
|
Habit | Herbs perennial, 4–10 cm, glabrous. | Herbs perennial, 25–38+ cm, pubescent. |
Stems | cespitose, matted, acaulescent. |
prostrate, branched. |
Leaves | 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. |
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, 1–4-flowered, umbellate, 1.5–2 × 0.5–1 cm, rachis not prolonged beyond flowers; involucres a narrow, membranous, dentate rim, 1 mm. |
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 | 0.5–3 cm. |
2.8–5 cm. |
Pedicels | erect, 1 mm; bracteoles cuplike, membranous, 0.5–1 mm. |
reflexed in fruit, 1–3 mm; bracteoles linear-triangular, 0.5 mm. |
Flowers | 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. |
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 | oblanceoloid, 9–11 mm. |
obovoid, 4.3–4.4 mm. |
Seeds | 4–6, tan or brown, mitten-shaped, 2–2.2 mm, smooth, dull. |
2, brownish orange or olive-brown, globose or broadly reniform, 1.2–1.7 mm, smooth. |
2n | = 16. |
= 16. |
Trifolium nanum |
Trifolium sonorense |
|
Phenology | Flowering Jun–Aug. | Flowering Aug–Oct. |
Habitat | Alpine slopes, tundra. | Dry stream banks, grassy places. |
Elevation | 2600–4500 m. (8500–14800 ft.) | 1500–1800 m. (4900–5900 ft.) |
Distribution |
CO; MT; NM; UT; WY
|
AZ; Mexico (Chihuahua, Jalisco, Sinaloa, Sonora) |
Discussion | 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.) |
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 | ||
Sibling taxa | ||
Name authority | Torrey: Ann. Lyceum Nat. Hist. New York 1: 35, plate 3, fig. 4. (1824) | T. K. Ahlquist & Vincent: Phytoneuron 2018-1: 1, fig. 1. (2018) |
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