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arrow-leaf clover

Thompson's clover

Habit Herbs annual, 15–70 cm, glabrous. Herbs perennial, 35–50 cm, antrorse-strigose.
Stems

erect or ascending, branched.

erect, branched.

Leaves

palmate;

stipules linear-lanceolate, 1–3.5 cm, margins entire, apex subulate or setaceous;

petiole 0.5–10 cm;

petiolules 1 mm;

leaflet 3, blades obovate to oblong, elliptic or lanceolate, 0.5–4 × 0.5–1.5 cm, base cuneate, veins prominent, thickened, margins spinulose-denticulate, apex apiculate, surfaces glabrous.

palmate;

stipules lanceolate, 3–4 cm, margins entire, apex acuminate;

petiole 5–20 cm;

petiolules to 1 mm;

leaflets 5–7, blades linear, linear-elliptic, linear-lanceolate, often folded, falcate, 2–7 × 0.2–0.6 cm, base cuneate, veins thickened, margins setose, apex acute-setiform, surfaces pubescent.

Inflorescences

terminal or axillary, 50–100+-flowered, globose, ovoid, or oblong, 3–6 × 2–3.5 cm;

involucres absent.

terminal, 60-flowered, in 10–12 whorls, globose or ovoid to subglobose, 3–5 × 3–4 cm;

involucres absent.

Peduncles

1–12 cm.

10–15 cm.

Pedicels

absent;

bracteoles lanceolate, 6–7 mm, acuminate.

reflexed in fruit, 1–1.5 mm;

bracteoles minute.

Flowers

12–16 mm;

calyx urceolate, not bilabiate, inflated in fruit, 6–10 mm, glabrous, veins 20–36, connected by transverse veins in fruit, tube 3–5 mm, lobes reflexed, subequal, subulate, as long as tube, orifice constricted;

corolla white becoming pink, 12–15 mm, banner ovate, broadly clawed, striate, 12–15 × 2–4 mm, apex acute-acuminate.

20–23 mm;

calyx campanulate, 6–8 mm, slightly pilose, veins 10–15, tube 2.5–3 mm, lobes equal, subulate, slightly pilose, orifice open;

corolla rose-pink to purple, 18–22 mm, banner oblong, folded, 18–22 × 11–13 mm, apex rounded.

Legumes

ellipsoid, 2.5–2.5 mm, shorter than calyx.

flattened, lanceoloid-oblong, 6 mm.

Seeds

2 or 3, brown, ovoid, 1–1.5 mm, roughened.

1 or 2, yellow, often mottled, mitten-shaped, 2.8–3 mm, smooth, glossy.

2n

= 16.

= 16.

Trifolium vesiculosum

Trifolium thompsonii

Phenology Flowering Apr–Jul. Flowering May–Jun.
Habitat Fields, roadsides, forest openings. Dry talus fans at base of slopes.
Elevation 0–1000 m. (0–3300 ft.) 100–300 m. (300–1000 ft.)
Distribution
from FNA
AL; AR; CA; FL; GA; LA; MA; MO; MS; OK; OR; SC; TX; VA; WA; s Europe; e Europe; w Asia [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
from FNA
WA
[WildflowerSearch map]
[BONAP county map]
Discussion

Trifolium vesiculosum was first introduced into cultivation in the United States in 1963 and is grown in southern and western states (J. D. Miller and H. D. Wells 1985).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Trifolium thompsonii is known from Chelan and Douglas counties (J. E. Canfield 1977). It is in the Center for Plant Conservation’s National Collection of Endangered Plants.

(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
T. albopurpureum, T. alexandrinum, T. amoenum, T. amphianthum, T. andersonii, T. andinum, T. angustifolium, T. appendiculatum, T. arvense, T. attenuatum, T. aureum, T. barbigerum, T. barnebyi, T. beckwithii, T. bejariense, T. bifidum, T. bolanderi, T. brandegeei, T. breweri, T. buckwestiorum, T. calcaricum, T. campestre, T. carolinianum, T. cernuum, T. ciliolatum, T. columbinum, T. cyathiferum, T. dasyphyllum, T. dedeckerae, T. depauperatum, T. dichotomum, T. douglasii, T. dubium, T. echinatum, T. eriocephalum, T. fragiferum, T. friscanum, T. fucatum, T. glomeratum, T. gracilentum, T. grayi, T. gymnocarpon, T. haydenii, T. hirtum, T. howellii, T. hybridum, T. hydrophilum, T. incarnatum, T. jokerstii, T. kentuckiense, T. kingii, T. lappaceum, T. latifolium, T. leibergii, T. lemmonii, T. longipes, T. lupinaster, T. macilentum, T. macraei, T. macrocephalum, T. medium, T. microcephalum, T. microdon, T. monanthum, T. mucronatum, T. nanum, T. nigrescens, T. obtusiflorum, T. oliganthum, T. ornithopodioides, T. owyheense, T. palmeri, T. parryi, T. pinetorum, T. piorkowskii, T. plumosum, T. polyodon, T. pratense, T. productum, T. reflexum, T. repens, T. resupinatum, T. retusum, T. rollinsii, T. siskiyouense, T. sonorense, T. stoloniferum, T. striatum, T. subterraneum, T. suffocatum, T. thompsonii, T. tomentosum, T. trichocalyx, T. variegatum, T. virginicum, T. willdenovii, T. wormskioldii
T. albopurpureum, T. alexandrinum, T. amoenum, T. amphianthum, T. andersonii, T. andinum, T. angustifolium, T. appendiculatum, T. arvense, T. attenuatum, T. aureum, T. barbigerum, T. barnebyi, T. beckwithii, T. bejariense, T. bifidum, T. bolanderi, T. brandegeei, T. breweri, T. buckwestiorum, T. calcaricum, T. campestre, T. carolinianum, T. cernuum, T. ciliolatum, T. columbinum, T. cyathiferum, T. dasyphyllum, T. dedeckerae, T. depauperatum, T. dichotomum, T. douglasii, T. dubium, T. echinatum, T. eriocephalum, T. fragiferum, T. friscanum, T. fucatum, T. glomeratum, T. gracilentum, T. grayi, T. gymnocarpon, T. haydenii, T. hirtum, T. howellii, T. hybridum, T. hydrophilum, T. incarnatum, T. jokerstii, T. kentuckiense, T. kingii, T. lappaceum, T. latifolium, T. leibergii, T. lemmonii, T. longipes, T. lupinaster, T. macilentum, T. macraei, T. macrocephalum, T. medium, T. microcephalum, T. microdon, T. monanthum, T. mucronatum, T. nanum, T. nigrescens, T. obtusiflorum, T. oliganthum, T. ornithopodioides, T. owyheense, T. palmeri, T. parryi, T. pinetorum, T. piorkowskii, T. plumosum, T. polyodon, T. pratense, T. productum, T. reflexum, T. repens, T. resupinatum, T. retusum, T. rollinsii, T. siskiyouense, T. sonorense, T. stoloniferum, T. striatum, T. subterraneum, T. suffocatum, T. tomentosum, T. trichocalyx, T. variegatum, T. vesiculosum, T. virginicum, T. willdenovii, T. wormskioldii
Synonyms Lupinaster thompsonii
Name authority Savi: Fl. Pis. 2: 165. (1798) — (as vessiculosum) C. V. Morton: J. Wash. Acad. Sci. 23: 270. (1933)
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