Trifolium tomentosum |
Trifolium subterraneum |
|
---|---|---|
woolly clover |
burrowing clover, subclover, subterranean clover, subterranean trefoil |
|
Habit | Herbs annual, 10–20 cm, glabrous or sparsely hairy. | Herbs annual, 10–80 cm, glabrous or appressed-pubescent. |
Stems | prostrate, ascending, or erect, branched. |
prostrate to ascending, branched. |
Leaves | palmate; stipules ovate or triangular-lanceolate, 0.4–1.2 cm, margins entire, apex acute or acuminate; petiole 0.5–7 cm; petiolules to 1 mm; leaflets 3, blades obovate, obcordate, or elliptic, 0.4–1.5 × 0.3–1 cm, base cuneate, veins moderately prominent, margins denticulate, apex rounded or emarginate, surfaces sparsely hairy abaxially, glabrous adaxially. |
palmate; stipules ovate, 0.5–3 cm, margins entire or slightly toothed, ciliate, apex acute to acuminate; petiole 1–20 cm; petiolules 1 mm; leaflets 3, blades broadly obcordate, 0.8–2.8 × 1–3 cm, base cuneate, veins delicate, widely spaced, margins mostly entire, slightly dentate distally, apex emarginate, surfaces appressed-sericeous. |
Inflorescences | axillary, 10–20-flowered, subglobose, soon becoming globose, flowers resupinate, calyces densely white-woolly, compacted, inflated, 0.5–1.5 × 0.5–1.5 cm; involucres a narrow rim, 0.2 mm. |
axillary, elongate and reflexed, pushing into substrate after anthesis, fertile flowers 2–7, sterile flowers 0–80, globose or cylindric, 0.5–1.5 × 0.8–1.5 cm; involucres absent. |
Peduncles | 0.5–1.5 cm. |
2–6.5 cm. |
Pedicels | slightly reflexed, to 0.5 mm; bracteoles cup-shaped, membranous, 0.2 mm. |
reflexed after anthesis, 0.2–0.4 mm; bracteoles absent. |
Flowers | 3–7 mm; calyx tubular, inflated in fruit, markedly asymmetric-bilabiate, 2–6 mm, woolly adaxially, veins 5–10, connected by lateral veins, tube 1.5–2.5 mm, 4–5 mm in fruit, lobes unequal, subulate, shorter than tube, adaxial spreading or curved, orifice open, abruptly constricted in fruit; corolla pink, 3–6 mm, banner ovate, 3–6 × 3–6 mm, apex emarginate to crenulate. |
fertile ones 7–15 mm; calyx tubular, 5–6 mm, glabrous or hairy, veins indistinct, tube 3–4 mm, lobes subequal, pubescent or glabrous, spreading, orifice open; corolla white, pink, or pink-striped, 7–10 mm, banner ovate-elliptic, 7–10 × 1.5–2 mm, apex rounded; sterile flowers 4–7 mm; calyx teeth linear; corolla absent. |
Legumes | ovoid to globose, 2–3 mm. |
subterranean, obovoid, 3–4 mm. |
Seeds | 1 or 2, yellow to brown, mottled, mitten-shaped, 0.9–1.1 mm, smooth, glossy. |
1, purplish black, ellipsoid, 2.6–3 mm, smooth, dull. |
2n | = 16. |
= 16. |
Trifolium tomentosum |
Trifolium subterraneum |
|
Phenology | Flowering Feb–Apr. | Flowering Mar–May. |
Habitat | Sandy lawns, fields, meadows, roadsides, clay soils among vernal pools. | Open, disturbed sandy soils. |
Elevation | 0–400 m. (0–1300 ft.) | 0–1000 m. (0–3300 ft.) |
Distribution |
CA; FL; MA; NC; SC; s Europe (Mediterranean); sw Asia; n Africa; Atlantic Islands (Azores) [Introduced in North America; introduced also in South America (Chile), s Africa, Pacific Islands (New Zealand), Australia]
|
CA; GA; LA; MA; MS; NC; NJ; OR; SC; WA; BC; w Europe; w Asia; n Africa [Introduced in North America; introduced also in s South America, s Africa, Pacific Islands (Hawaii, New Zealand), Australia]
|
Discussion | Trifolium tomentosum is occasionally cultivated as a forage crop (F. J. Hermann 1953) and is becoming weedy in the flora area and in Australia (R. P. Randall 2002). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Trifolium subterraneum was first introduced by the USDA about 1921 as a pasture crop; it is utilized as such in the western and southern United States (W. S. McGuire 1985). Inflorescences of T. subterraneum consist of intermixed sterile and fertile flowers; after fetilization, the inflorescence is pushed underground, where the fruits develop. (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 | Linnaeus: Sp. Pl. 2: 771. (1753) | Linnaeus: Sp. Pl. 2: 767. (1753) |
Web links |
|