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bull clover, sour clover

knotted clover

Habit Herbs annual, 10–80 cm, glabrous or glabrescent. Herbs usually annual, rarely biennial, 10–50 cm, villous.
Stems

erect or ascending, unbranched or densely dichotomously branched.

erect, ascending, or decumbent, branched from base.

Leaves

palmate;

stipules ovate or lanceolate, 1–3 cm, margins entire or toothed, apex usually acuminate, sometimes 2-fid;

petiole 3–15 cm;

petiolules 1–1.5 mm;

leaflets 3, blades broadly obovate, orbiculate, or rhombic-obovate, 0.8–4 × 0.7–3 cm, base broadly cuneate, veins obscure, thickened near leaflet margin, margins remotely dentate to densely serrulate-dentate, apex rounded or slightly retuse, surfaces glabrous or glabrate.

palmate;

stipules lanceolate-ovate, 0.9–1.1 cm, margins entire, apex acute-acuminate, setaceous, ciliate;

petiole 0.5–5 cm;

petiolules 0.5 mm;

leaflets 3, blades obovate to oblong, 0.9–1.6 × 0.4–1 cm, base cuneate, veins fine, margins denticulate, apex obtuse, obcordate, or emarginate, surfaces hairy.

Inflorescences

terminal or axillary, 10–30-flowered, subglobose or globose, 1–4 × 1–4 cm;

involucres broadly bowl-shaped, 4–15 mm, lobes 3–8, lanceolate, acuminate, undivided or 2- or 3-fid.

axillary or terminal, solitary or paired, 20–60-flowered, ovoid or oblong, 0.8–1.6 × 0.6–1 cm;

involucres absent.

Peduncles

3–13 cm.

0–1 cm.

Pedicels

straight, 1 mm;

bracteoles distinct or connate, broadly ovate, 1 mm.

absent;

bracteoles absent.

Flowers

10–27 mm;

calyx campanulate, 3–8 mm, glabrous, veins 10, tube 1.5–2.5 mm, lobes 5–10, unequal, undivided or 3-fid, long-acuminate, orifice open;

corolla creamy white to yellow, pink to purple in age, keel petals rarely dark purple, 10–27 mm, banner broadly ovate, inflated in fruit, not distally twisted, 10–27 × 6–15 mm, apex rounded, erose.

5–7 mm;

calyx ellipsoid to urceolate, 3–4 mm, hairy, veins 10, tube 2–3 mm, lobes erect or spreading, unequal, abaxial longest and equal to tube, subulate, orifice open;

corolla pink, 25–35 mm, banner oblong, 2.5–3.5 × 1.5–2 mm, apex retuse.

Legumes

stipitate, linear, 7–8 mm.

ovoid, leathery distally, transversely dehiscent, 2–2.5 mm.

Seeds

3–8, gray, mottled, globose, 1.6–2 mm, reticulate.

1, tan or reddish brown, globose to ovoid, 1–1.5 mm, smooth, glossy.

2n

= 16.

= 14.

Trifolium fucatum

Trifolium striatum

Phenology Flowering Apr–Jun. Flowering May–Aug.
Habitat Moist places, meadows, road­sides. Waste places
Elevation 0–1000 m. (0–3300 ft.) 0–500 m. (0–1600 ft.)
Distribution
from FNA
CA; OR; WA [Introduced in Asia (China, Japan)]
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CA; GA; MA; MO; NC; NJ; NY; OK; OR; PA; SC; VA; VT; WA; BC; Europe; w Asia; nw Africa [Introduced also in s South America (Chile), Pacific Islands (New Zealand), Australia]
[WildflowerSearch map]
[BONAP county map]
Discussion

Trifolium fucatum is known as an invasive species in Japan (T. Mito and T. Uesugi 2004) and has also been introduced in China (specimen at BM). A single old collection exists from British Columbia, but the species has not been collected in that province again. The Michigan record of the species is an inadvertent waif.

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

Trifolium striatum has been recorded as an occasional weed in the flora area, having been first collected on ballast in New Jersey in 1880. It is found sporadically as a weed of disturbed habitats and appears to be spreading rapidly. It has been called Pitts’s clover in the southern United States because it was discovered by J. D. Pitts in a field of crimson clover as a weed and he experimented with it as a forage plant (G. L. Fuller and B. H. Hendrickson 1928).

(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. 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. vesiculosum, 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. subterraneum, T. suffocatum, T. thompsonii, T. tomentosum, T. trichocalyx, T. variegatum, T. vesiculosum, T. virginicum, T. willdenovii, T. wormskioldii
Synonyms T. flavulum, T. fucatum var. flavulum, T. fucatum var. gambelii, T. fucatum var. virescens, T. gambelii, T. physopetalum, T. virescens
Name authority Lindley: Edwards’s Bot. Reg. 22: plate 1883. (1836) Linnaeus: Sp. Pl. 2: 770. (1753)
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