Trifolium buckwestiorum |
Trifolium amphianthum |
|
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Santa Cruz clover |
peanut clover |
|
Habit | Herbs annual, 5–40 cm, glabrous. | Herbs perennial, 10–25 cm, glabrous or glabrate. |
Stems | decumbent to ascending or erect, slightly branched. |
creeping, branched, rooting at nodes. |
Leaves | 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. |
palmate; stipules ovate-lanceolate, 0.5–1 cm, margins entire, apex acute to acuminate; petiole 3–10 cm; petiolules 0.5–1 mm; leaflets 3, blades obcordate, 0.5–1.8 × 0.5–1.5 cm, base cuneate, veins thickened, margins entire or denticulate distally, apex usually deeply emarginate, rarely rounded, surfaces glabrous. |
Inflorescences | 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. |
axillary, 5–20-flowered, globose, 1–2.2 × 1–20 cm, chasmogamous erect, cleistogamous becoming subterranean; involucres formed of distinct, narrowly lanceolate bracts, 2.5–3.5 mm. |
Peduncles | 1–3.5 cm. |
chasmogamous 6–8 cm, cleistogamous ± sessile. |
Pedicels | straight, to 0.5 mm; bracteoles absent. |
reflexed in fruit, cleistogamous pushing fruit underground, chasmogamous 1–8 mm, cleistogamous 4–20 mm; bracteoles lanceolate, 2–4 mm. |
Flowers | 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. |
chasmogamous 8–11 mm, cleistogamous 4–5 mm; calyx campanulate, 3–5 mm, slightly pilose, veins 10, tube 1.5–2 mm, lobes subequal, adaxial pair connate proximally, sometimes nearly entire length, narrowly triangular-subulate, orifice open; corolla magenta or pink, 7.5–11 mm, banner broadly obovate-elliptic, 5–10 × 5–8 mm, apex rounded, emarginate. |
Legumes | ovoid, 2.5 mm. |
stipitate, chasmogamous ellipsoid, cleistogamous ovoid-globose, chasmogamous longitudinally dehiscent, 3–6 mm, cleistogamous indehiscent, 3–6 mm. |
Seeds | 1, dark brown, slightly mottled, ovoid, 2 mm, smooth. |
2–6 (chasmogamous), 1–3 (cleistogamous), tan, mitten-shaped, 1.2–1.5 mm, smooth. |
2n | = 16, 32. |
|
Trifolium buckwestiorum |
Trifolium amphianthum |
|
Phenology | Flowering May–Jun. | Flowering Mar–Jun. |
Habitat | Meadows, roadsides, grassy hillsides. | Sandy soils, prairies. |
Elevation | 0–300 m. (0–1000 ft.) | 0–200 m. (0–700 ft.) |
Distribution |
CA |
LA; TX |
Discussion | 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.) |
Trifolium amphianthum ranges in east-central Texas from Aransas County northward to Denton County, and eastward to San Augustine and Shelby counties; it is also recorded from Natchitoches and Rapides parishes in Louisiana. Trifolium amphianthum was collected once in Arkansas, but the specimen may have been from cultivation. The name Trifolium polymorphum Poiret applies to plants found in Argentina, Brazil, Paraguay, and Uruguay and has been misapplied to this North American endemic, as was done by M. Zohary and D. Heller (1984). Trifolium amphianthum is distinguished from T. polymorphum by its much larger leaves and flowers and essentially glabrous leaves and peduncles. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | T. roemerianum | |
Name authority | Isely: Madroño 39: 90, fig. 2. (1992) | Torrey & A. Gray: Fl. N. Amer. 1: 316. (1838) |
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