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olive clover

Palmer's clover, southern island clover

Habit Herbs annual, 8–30 cm, canescent. Herbs annual, 4–40 cm, glabrous.
Stems

erect, branched from base and distally, or unbranched.

erect or ascending, 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 lanceolate, 0.5–2.5 cm, margins entire or slightly serrate, apex acuminate;

petiole 0.5–5 cm;

petiolules to 1 mm;

leaflets 3, blades narrowly elliptic or lanceolate, 0.8–3 × 0.3–0.8 cm, base cuneate, veins thickened, margins setose-serrulate, apex 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, 10–20-flowered, globose to subglobose, 0.5–2 × 0.5–2 cm, rachis prolonged beyond flowers;

involucres absent.

Peduncles

3–11 cm.

1–5 cm.

Pedicels

absent;

bracteoles cuplike, to 0.5 mm.

becoming dramatically reflexed, 3–4 mm;

bracteoles low, broadly triangular, membranous, to 0.5 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.

5–9 mm;

calyx narrowly campanulate, 5–6.5 mm, glabrous, veins 10, tube 2–3 mm, lobes unequal, narrowly triangular to acicular, margins green or purple, membranous, orifice open;

corolla pink or purple, 5–9 mm, banner narrowly elliptic-oblong, 5–9 × 3–4 mm, apex narrowly rounded to acute.

Legumes

obovoid, 3–3.5 mm.

ovoid-ellipsoid, 4–6 mm.

Seeds

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

1 or 2, yellow, purple-mottled, mitten-shaped, 2 mm, smooth.

2n

= 16.

Trifolium columbinum

Trifolium palmeri

Phenology Flowering Apr–May. Flowering Mar–Jun.
Habitat Grassy slopes, meadows, heavy adobe/clay soils, oak woodland foothills. Thin soils on slopes.
Elevation 0–1400 m. (0–4600 ft.) 0–50 m. (0–200 ft.)
Distribution
from FNA
CA
from FNA
CA; Mexico (Baja California)
[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 palmeri is known from the islands off the coast of southern California and Baja California, Mexico. It was long considered a variety of T. gracilentum but molecular analyses support its recognition as distinct (N. W. Ellison et al. 2006).

(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. 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. 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. gracilentum var. palmeri
Name authority Greene: Pittonia 1: 4. (1887) S. Watson: Proc. Amer. Acad. Arts 11: 132. (1876)
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