Trifolium dubium |
Trifolium brandegeei |
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least hop clover, lesser hop clover, lesser hop trefoil, little hop clover, shamrock, small hop-clover, suckling clover |
Brandegee's clover |
|
Habit | Herbs annual, 20–40 cm, glabrous or sparsely hairy. | Herbs perennial, 5–15 cm, glabrous. |
Stems | erect to prostrate, branched from base. |
cespitose, short-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 broadly lanceolate, 1–1.5 cm, margins entire, apex acute-acuminate; petiole 0.6–1.2 cm; petiolules to 0.5 mm; leaflets 3, blades ovate, oblong-elliptic, or elliptic, 0.8–3 × 0.4–1.5 cm, base cuneate, veins moderately thickened, margins entire or faintly serrate, apex acute to rounded or minutely apiculate, surfaces glabrous. |
Inflorescences | axillary or terminal, 5–20-flowered, ovoid or globose, 0.5–0.9 × 0.6 cm; involucres absent. |
terminal, 4–15-flowered, ovoid-ellipsoid, 2.5–4 × 2.2–3 cm, rachis prolonged ca. 10 mm beyond distalmost flower; involucres absent. |
Peduncles | 1–1.5 cm. |
6–20 cm. |
Pedicels | reflexed, 0.2–0.5 mm; bracteoles a fringe of red setae. |
strongly reflexed, 1–2 mm; bracteoles linear, minute. |
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. |
15–18 mm; calyx whitish, campanulate, 7–10 mm, sparsely pubescent, veins 10, tube 4–5 mm, lobes subequal, longer than tube, narrowly triangular, acuminate, orifice open; corolla purple to magenta, 15–18 mm, banner broadly ovate, 15–17 × 7–9 mm, apex obtuse or retuse. |
Legumes | stipitate, ellipsoid, 1.5–2 mm, short beaked. |
oblong, 6.5–7 mm. |
Seeds | 1, yellow or pale brown, ellipsoid, 0.9–1 mm, smooth, glossy. |
1–3, yellow and red, flattened ovoid, 2–2.5 mm, smooth. |
2n | = 16, 28, 32. |
= 16. |
Trifolium dubium |
Trifolium brandegeei |
|
Phenology | Flowering May–Oct. | Flowering Jul–Aug. |
Habitat | Disturbed ground, fields. | Open montane forests and subalpine areas. |
Elevation | 0–2300 m. (0–7500 ft.) | 3500–3700 m. (11500–12100 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]
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CO; NM
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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.) |
A close relationship between Trifolium brandegeei and T. parryi was hypothesized by J. M. Gillett (1965); this has not been borne out by flavonoid chemosystematics (E. V. Parups et al. 1966) or DNA analyses (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 | |
Name authority | Sibthorp: Fl. Oxon., 231. (1794) | S. Watson: Proc. Amer. Acad. Arts 11: 130. (1876) — (as brandegei) |
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