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bull clover, sour clover

olive clover

Habit Herbs annual, 10–80 cm, glabrous or glabrescent. Herbs annual, 8–30 cm, canescent.
Stems

erect or ascending, unbranched or densely dichotomously branched.

erect, branched from base and distally, or unbranched.

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 ovate, 0.4–1.2 cm, margins entire, ciliate, apex often purple, acuminate, setaceous;

petiole 0.5–8 cm;

petiolules 0.5–1 mm;

leaflets 3, blades obovate or elliptic, 0.5–3 × 0.3–1.2 cm, base cuneate, veins obscure or slightly thickened, margins dentate, apex rounded or emarginate, surfaces pilose.

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.

terminal or axillary, 25–50-flowered, ovoid-ellipsoid, 1–2.5 × 1.2–2.5 cm;

involucres absent.

Peduncles

3–13 cm.

3–11 cm.

Pedicels

straight, 1 mm;

bracteoles distinct or connate, broadly ovate, 1 mm.

absent;

bracteoles cuplike, to 0.5 mm.

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.

6–10 mm;

calyx tubular, 8–14 mm, densely pubescent, veins 20–30, tube 1–2 mm, lobes nearly equal, appearing rigidly erect, linear-setaceous, plumose, sinuses acute, orifice open;

corolla sometimes absent, red-violet, often with white tips, 4–6 mm, banner ovate-oblong, 7–8 × 2–3 mm, apex broadly rounded, apiculate.

Legumes

stipitate, linear, 7–8 mm.

obovoid, 3–3.5 mm.

Seeds

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

1, yellow-brown, ellipsoid, 2–2.5 mm, smooth.

2n

= 16.

Trifolium fucatum

Trifolium columbinum

Phenology Flowering Apr–Jun. Flowering Apr–May.
Habitat Moist places, meadows, road­sides. Grassy slopes, meadows, heavy adobe/clay soils, oak woodland foothills.
Elevation 0–1000 m. (0–3300 ft.) 0–1400 m. (0–4600 ft.)
Distribution
from FNA
CA; OR; WA [Introduced in Asia (China, Japan)]
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
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.)

D. Isely (1998) stated that Central Valley populations of Trifolium columbinum appeared to be extinct and populations outside that region (and here recognized as the same taxon) were similar in calyx and corolla proportions. It is rather widespread in California, ranging from Humboldt County southward to Santa Barbara County, and eastward into counties ranging from Shasta southward to Inyo, Kern, and Placer counties.

Trifolium albopurpureum var. olivaceum (Greene) Isely and T. columbinum var. olivaceum (Greene) Jepson are illegitimate names that pertain here (D. J. Keil 2019).

(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. 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. 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 T. albopurpureum var. columbinum, T. columbinum var. argillorum, T. olivaceum, T. olivaceum var. columbinum, T. olivaceum var. griseum
Name authority Lindley: Edwards’s Bot. Reg. 22: plate 1883. (1836) Greene: Pittonia 1: 4. (1887)
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