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olive clover

foothill clover, tree clover

Habit Herbs annual, 8–30 cm, canescent. Herbs annual, 5–50 cm, glabrous or sparsely hairy.
Stems

erect, branched from base and distally, or unbranched.

erect, branched.

Leaves

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.

palmate;

stipules ovate-lanceolate, 1–1.5 cm, margins entire, sometimes ciliate, apex acuminate;

petiole 1–13 cm;

petiolules 0.5 mm;

leaflets 3, blades elliptic to oblong or obovate, 0.8–3.5 × 0.5–1.5 cm, base cuneate, veins thickened, margins serrate proximally, obscurely denticulate distally, apex usually rounded or retuse, rarely acute, surfaces glabrous.

Inflorescences

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

involucres absent.

axillary or terminal, 10–30-flowered, ovoid to subglobose, 0.7–2.2 × 0.5–2 cm;

involucres a narrow rim, 0.5 mm, membranous, dentate.

Peduncles

3–11 cm.

2.5–12 cm.

Pedicels

absent;

bracteoles cuplike, to 0.5 mm.

erect becoming reflexed, 0.5–6 mm;

bracteoles linear or cup-shaped, to 1 mm.

Flowers

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.

6–13 mm;

calyx broadly campanulate, 5–11 mm, glabrous, veins 10, tube 1–5 mm, lobes unequal, elliptic to linear, margins hyaline, dentate or pectinate, ciliate, sinuses narrow, orifice open;

corolla white, pink, or purple, 5–13 mm, banner broadly ovate, 6–13 × 4–7 mm, apex rounded, apiculate.

Legumes

obovoid, 3–3.5 mm.

short-stipitate, ovoid, 5–10 mm.

Seeds

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

1 or 2, brown, mottled, ovoid, 2.5–3 mm, smooth.

2n

= 16.

Trifolium columbinum

Trifolium ciliolatum

Phenology Flowering Apr–May. Flowering Apr–Jun.
Habitat Grassy slopes, meadows, heavy adobe/clay soils, oak woodland foothills. Oak-pine chaparral, meadows, roadsides.
Elevation 0–1400 m. (0–4600 ft.) 0–1500 m. (0–4900 ft.)
Distribution
from FNA
CA
from FNA
CA; OR; WA; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
Discussion

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.)

Trifolium ciliolatum is relatively widespread in California and is found in scattered sites in Baja California, Oregon, and Washington.

Trifolium ciliatum Nuttall (1848), which pertains here, is a later homonym of T. ciliatum E. D. Clarke (1813).

(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. 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
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. 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. vesiculosum, T. virginicum, T. willdenovii, T. wormskioldii
Synonyms T. albopurpureum var. columbinum, T. columbinum var. argillorum, T. olivaceum, T. olivaceum var. columbinum, T. olivaceum var. griseum T. ciliatum var. discolor
Name authority Greene: Pittonia 1: 4. (1887) Bentham: Pl. Hartw., 304. (1849)
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