Trifolium vesiculosum |
Trifolium macrocephalum |
|
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arrowleaf clover |
big-headed clover, largehead clover |
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Habit | Plants annual, erect or ascending, 15–70 cm, glabrous; branched. | Plants perennial, erect or ascending, 5–25 cm, villous; branched. |
Leaves | pinnate; leaflets 3, obovate to oblong, elliptic or lanceolate, 5–40 × 5–15 mm, bases cuneate; margins spinulose-denticulate; veins prominent, thickened; tips apiculate; surfaces glabrous; petioles 5–100 mm; petiolules ~1 mm; stipules linear-lanceolate, 10–35 mm; margins entire; tips subulate or setaceous. |
palmate; leaflets (5)7–9, broadly to narrowly obovate, often folded, 10–27 × 4–11 mm, bases cuneate; margins serrulate or irregularly lobed; veins thickened, especially distally; tips rounded or truncate, apiculate; surfaces abaxially villous, adaxially sparsely villous to glabrate; petioles 10–140 mm; petiolules 0.9–1.2 mm; stipules ovate, obovate, or oblong, 10–30 mm; margins entire. |
Inflorescences | terminal or axillary, 50–100+-flowered, globose; ovoid, or oblong, 30–60 × 20–35 mm; involucres absent; bracteoles lanceolate, 6–7 mm, nearly as long as calyces, acuminate. |
terminal, 20–32-flowered, globose or ovoid-ellipsoidal, 25–80 × 30–70 mm; involucres absent; bracteoles broadly ovate, membranous; ? 0.5 mm, truncate. |
Peduncles | 10–120 mm. |
20–80 mm. |
Pedicels | absent. |
erect, 1–1.5 mm. |
Flowers | 12–16 mm; calyces urceolate; symmetrical, inflated in fruit, 6–10 mm, glabrous; veins 20–36, connected transversely in fruit; tubes 3–5 mm; lobes reflexed, subulate, subequal; as long as tube; orifices constricted; corollas 12–15 mm, white becoming pink; banners ovate, broadly clawed, 12–15 × 2–4 mm, striate; tips acute-acuminate. |
20–30 mm; calyces campanulate, 10–22 mm, villous; veins 10–15; tubes 2.5–4 mm; lobes subulate, subequal, 2–4 × tube length, plumose; orifices open; corollas 20–28 mm, white; creamy white, or pinkish; banners ovate or oblong, 20–28 × 10–13 mm; tips rounded or slightly emarginate; keel petals deep pink. |
Fruits | ellipsoid, 2.5–3.5 mm; < calyces. |
longitudinally dehiscent; ovoid, 4–5 mm; ? calyces. |
Seeds | 2–3; ovoid, 1–1.5 mm, brown, roughened. |
1–2; mitten-shaped to ellipsoid, 2.5–3 mm, yellow or reddish; smooth. |
2n | =16. |
=32, 48. |
Trifolium vesiculosum |
Trifolium macrocephalum |
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Distribution | ||
Discussion | Fields, roadsides, forest openings. Flowering Jun–Aug. 0–300 m. CR, WV. CA, WA; southeastern US; Asia, Europe. Exotic. Trifolium vesiculosum is native to Eurasia and is a recently introduced forage crop, the first cultivar of which was introduced in 1963; it is cultivated in the southern and western United States. |
Rocky places, hard, compacted clay gumbo, lava beds, sage-covered slopes. Flowering Apr–Jul. 0–2200 m. BR, BW, Col, ECas, Lava, Owy. CA, ID, NV, WA. Native. Trifolium macrocephalum has the largest inflorescences of any species in the genus. The name T. megacephalum is an illegitimate replacement name for Lupinaster macrocephalum. |
Source | Flora of Oregon, volume 2, page 739 Michael Vincent |
Flora of Oregon, volume 2, page 734 Michael Vincent |
Sibling taxa | ||
Web links |
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