Trifolium dubium |
Trifolium barbigerum |
|
---|---|---|
least hop clover, lesser hop clover, lesser hop trefoil, little hop clover, shamrock, small hop-clover, suckling clover |
bearded clover |
|
Habit | Herbs annual, 20–40 cm, glabrous or sparsely hairy. | Herbs annual, 7–20 cm, puberulent or glabrous. |
Stems | erect to prostrate, branched from base. |
decumbent or erect, branched. |
Leaves | pinnate; stipules ovate, 0.3–0.5 cm, margins entire, apex acute; petiole to 1.5 cm; lateral leaflet petiolules to 0.5 mm, terminal leaflet stalk 1–1.5 mm; leaflets 3, blades obovate to elliptic-lanceolate, 1–2 × 0.5–1.5 cm, base cuneate, lateral veins prominent, ± parallel, ascending, margins dentate distally, apex rounded or retuse, surfaces glabrous or sparsely hairy. |
palmate; stipules ovate-lanceolate, 0.5–1.1 cm, margins toothed or lacerate, apex acute-acuminate; petiole 1–10 cm; petiolules to 0.5 mm; leaflets 3, blades oblanceolate or obovate, 1.5–2.5 × 0.4–0.7 cm, base cuneate, veins fine, thickened distally, margins ± serrate or entire, apex rounded or retuse, surfaces pubescent or glabrous. |
Inflorescences | axillary or terminal, 5–20-flowered, ovoid or globose, 0.5–0.9 × 0.6 cm; involucres absent. |
axillary or terminal, 5–20-flowered, subglobose or globose, 0.6–1.5 × 1–1.5 cm; involucres bowl-shaped, 5–15 mm, lobes 6–10, sharply setaceous-toothed, sinuses shallow. |
Peduncles | 1–1.5 cm. |
5–10 cm. |
Pedicels | reflexed, 0.2–0.5 mm; bracteoles a fringe of red setae. |
straight, 0.2 mm; bracteoles absent. |
Flowers | 2.8–3.5 mm; calyx campanulate, 1.5–2 mm, glabrous, veins 5, tube 0.8–1 mm, lobes unequal, longer than tube, adaxial 2 shorter, orifice open; corolla pale yellow becoming brown, 2.6–3.2 mm, not or slightly ribbed, banner persistent, spatulate, 2.6–3.2 × 2 mm, apex rounded to broadly acute. |
4–6 mm; calyx campanulate, 5–9 mm, usually pubescent, rarely glabrous, veins 5, tube 2–3 mm, lobes ± equal, setaceous, often exceeding banner, orifice open; corolla usually lavender to purple, usually with white tips, rarely wholly white, 5–8 mm, banner broadly oblong, proximally inflated in fruit, distally narrowed into twisted tip, 6–8 × 6–8 mm, apex broadly acute. |
Legumes | stipitate, ellipsoid, 1.5–2 mm, short beaked. |
ovoid-ellipsoid, 2–3 mm. |
Seeds | 1, yellow or pale brown, ellipsoid, 0.9–1 mm, smooth, glossy. |
1 or 2, brown, ellipsoid to subglobose, 1–1.5 mm, slightly roughened. |
2n | = 16, 28, 32. |
= 16. |
Trifolium dubium |
Trifolium barbigerum |
|
Phenology | Flowering May–Oct. | Flowering Apr–Jun. |
Habitat | Disturbed ground, fields. | Vernal pools, stream banks, meadows, lawns. |
Elevation | 0–2300 m. (0–7500 ft.) | 0–1300 m. (0–4300 ft.) |
Distribution |
AK; AL; AR; AZ; CA; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; TN; TX; VA; VT; WA; WI; WV; WY; BC; NB; NS; ON; PE; QC; SPM; c Europe; s Europe; w Asia [Introduced in North America; introduced also in s South America, e Asia (e China), n, s Africa, Pacific Islands (Hawaii, New Zealand), Australia]
|
CA; OR
|
Discussion | Trifolium dubium is often confused with Medicago lupulina Linnaeus; the latter may be distinguished by its toothed stipules, deciduous corollas, and shiny, black fruits. Little hop clover may be the co-called shamrock of Irish folklore (E. C. Nelson 1991; P. S. Wyse Jackson 2014); other candidates include other species of Trifolium or species of Medicago or Oxalis. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Trifolium barbigerum is relatively common and widespread in California, and extends northward into Coos, Curry, and Jackson counties in Oregon. It is morphologically similar to T. physanthum of Chile, to which it is a sister species in phylogenetic studies (N. W. Ellison et al. 2006). (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 | ||
Synonyms | Chrysaspis dubia, T. minus | T. minutissimum |
Name authority | Sibthorp: Fl. Oxon., 231. (1794) | Torrey in War Department [U.S.]: Pacif. Railr. Rep. 4(5): 79. (1857) |
Web links |
|