Trifolium macrocephalum |
Trifolium aureum |
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big-head clover, large-head clover |
golden clover, golden hop clover, greater hop clover, hop clover, large hop clover, large hop trefoil, palmate hop clover, yellow clover |
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Habit | Herbs perennial, 5–25 cm, villous. | Herbs annual, 20–60 cm, glabrous or hirsute. |
Stems | erect or ascending, branched. |
erect, unbranched or profusely branched. |
Leaves | palmate; stipules ovate, obovate, or oblong, 1–3 cm, margins entire, irregularly lobed, or serrate, apex acute or acuminate; petiole 1–14 cm; petiolules 0.9–1.2 mm; leaflets (5–)7–9, blades broadly to narrowly obovate, often folded, 1–2.7 × 0.4–1.1 cm, base cuneate, veins thickened, especially distally, margins serrulate, apex rounded or truncate, apiculate, surfaces villous abaxially, sparsely villous to glabrate adaxially. |
palmate; stipules oblanceolate, 0.9–1.5 cm, margins entire, apex acuminate or cuspidate; petiole 0.8–1 cm; petiolules 0–1 mm; leaflets 3, blades obovate to elliptic-lanceolate, 1–2.8 × 0.6–0.8 cm, base cuneate, lateral veins prominent, ± parallel, ascending, margins denticulate, apex acute, truncate, or retuse, mucronate, surfaces glabrous or sparsely hairy. |
Inflorescences | terminal, 20–32-flowered, globose or ovoid-ellipsoid, 2.5–8 × 3–7 cm; involucres absent. |
axillary or terminal, 20–80-flowered, usually ovoid-cylindric, sometimes globose, 1.2–2 × 1.3 cm; involucres absent. |
Peduncles | 2–8 cm. |
2–5 cm. |
Pedicels | erect, 1–1.5 mm; bracteoles broadly ovate, membranous, to 0.5 mm, truncate. |
reflexed, 0.3–0.6 mm; bracteoles a fringe of red setae. |
Flowers | 20–30 mm; calyx campanulate, 10–22 mm, villous, veins 10–15, tube 2.5–4 mm, lobes subequal, subulate, plumose, orifice open; corolla white, creamy white, or pinkish, keel petals deep pink, 20–28 mm, banner ovate or oblong, 20–28 × 10–13 mm, apex rounded or slightly emarginate. |
7–8 mm; calyx campanulate, 2–2.5 mm, glabrous, veins 5, tube 0.8–1 mm, lobes unequal, adaxial deltate, 0.6–0.9 mm, 1/2 length of abaxial, abaxial linear, orifice open; corolla golden yellow becoming brown, 5–6 mm, banner persistent, obovate, boat-shaped, 4–4.5 × 2.4–2.6 mm, apex emarginate. |
Legumes | ovoid, 4–5 mm. |
stipitate, oblong, 3–3.5 mm, longer than calyx. |
Seeds | 1 or 2, yellow or reddish, mitten-shaped to ellipsoid, 2.5–3 mm, smooth. |
1, pale yellow-green, ovoid, 1–1.2 mm, smooth, glossy. |
2n | = 32, 48. |
= 14, 16. |
Trifolium macrocephalum |
Trifolium aureum |
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Phenology | Flowering Apr–Jun. | Flowering Jun–Aug. |
Habitat | Rocky places, hard, compacted clay-gumbo, lava beds, sage-covered slopes, full sun. | Roadsides, railroads, fields, disturbed woodland glades. |
Elevation | 80–2500 m. [260–8200 ft.] | 0–1700 m. [0–5600 ft.] |
Distribution |
CA; ID; NV; OR; WA
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AK; CA; CT; DC; DE; GA; IA; ID; IL; IN; KY; MA; MD; ME; MI; MN; MO; MT; NC; NH; NJ; NY; OH; OR; PA; RI; SC; TN; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; ON; PE; QC; SK; SPM; n Europe; c Europe; w Asia [Introduced in North America; introduced also in s South America (Argentina, Chile), e Asia (e China), Pacific Islands (New Zealand), Australia]
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Discussion | Trifolium macrocephalum has the largest inflorescences of any clover. Trifolium megacephalum Nuttall (1818) is an illegitimate replacement name for Lupinaster macrocephalum Pursh. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Trifolium agrarium Linnaeus is a rejected name that has been used historically for T. aureum (J. E. Dandy 1958; N. J. Turland et al. 1996). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Lupinaster macrocephalum | Chrysaspis aurea |
Name authority | (Pursh) Poiret in J. Lamarck et al.: Encycl., suppl. 5: 336. (1817) | Pollich: Hist. Pl. Palat. 2: 344. (1777) |
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