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notch-leaf clover, Pinole clover, piñole clover

canyon clover, Howell's clover

Habit Herbs annual, 5–55 cm, sparsely pubescent or glabrous. Herbs perennial, 30–100 cm, glabrous.
Stems

erect, branched.

erect, fistulose, unbranched or branched distally.

Leaves

palmate;

stipules ovate to lanceolate, 0.8–1.5 cm, margins entire or slightly serrate, apex acicular;

petiole 1–7 cm;

petiolules to 0.5 mm;

leaflets 3, blades narrowly obcordate, obovate, oblanceolate, or linear, 1–2.5 × 0.3–0.7 cm, base cuneate, veins moderately thickened, margins serrate distally or entire, apex rounded, truncate, shallowly to deeply retuse, or deeply 2-fid, surfaces glabrous or hairy abaxially along midvein.

palmate;

stipules ovate, 1.5–4.5 cm, margins usually entire, sometimes lobed, apex acuminate;

petiole 0.5–20 cm;

petiolules 1–1.5 mm;

leaflets 3, blades ovate, elliptic, or rhombic, 3.5–9.5 × 2.3–5 cm, base cuneate, veins obscure, margins ± serrate, apex acute, rounded, or obtuse, surfaces glabrous.

Inflorescences

axillary or terminal, 5–30-flowered, globose to subglobose, 0.8–1.5 × 0.8–1.5 cm, rachis prolonged beyond flowers;

involucres a very narrow rim, to 0.5 mm.

terminal or axillary, 20–70-flowered, globose or ellipsoid, 2.5–4 × 2–2.5 cm, rachis prolonged beyond flowers, undivided or forked, often bearing sterile flower buds distally;

involucres absent.

Peduncles

3–8 cm.

3–11 cm.

Pedicels

reflexed in fruit, 1–3 mm;

bracteoles broadly triangular, membranous, to 0.5 mm.

strongly reflexed in fruit, 1 mm;

bracteoles minute, blunt or acute, membranous.

Flowers

6–8 mm;

calyx campanulate, 3–3.6 mm, slightly hairy or glabrous, veins 10, tube 1–1.5 mm, lobes unequal, subulate, margins green or purple, orifice open;

corolla pink or purple, 5–7 mm, banner elliptic to oblong, 5–7 × 3–4 mm, apex rounded, apiculate.

10–14 mm;

calyx campanulate, gibbous, 4–5.5 mm, glabrous, veins 10, tube 2–2.5 mm, lobes subequal, linear-lanceolate, orifice open;

corolla white, lemon yellow, or greenish yellow, 11–12 mm, banner elliptic-oblong, 11–12 × 4–5 mm, apex obtuse.

Legumes

stipitate, obovoid, 3–4 mm.

oblong or clavate, 4–5 mm.

Seeds

1 or 2, brown, mottled, oblong, 2–3 mm, smooth.

1–3, reddish black or brown, angular, mitten-shaped, 2.5 mm, smooth or slightly roughened, dull.

2n

= 16.

Trifolium bifidum

Trifolium howellii

Phenology Flowering Apr–Jun. Flowering Jun–Jul.
Habitat Open woodlands, fields, road­sides, slopes, stream margins, meadows. Wet stream banks, wet meadows, flood plains, shady woodlands, springs, thickets.
Elevation 0–1200 m. (0–3900 ft.) 800–2000 m. (2600–6600 ft.)
Distribution
from FNA
CA; OR; WA; BC; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR
[WildflowerSearch map]
[BONAP county map]
Discussion

Trifolium bifidum ranges from Baja California, Mexico, northward through California to scattered sites in Oregon, Washington, and British Columbia.

Recent re-evaluation of Trifolium bifidum and related species showed complete overlap in characters for the two varieties that have been recognized previously, with no clear distinctions between them (L. Rogers, pers. comm.).

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

Trifolium howellii is known from Del Norte, Humboldt, Siskiyou, and Trinity counties in California, and Clackamas, Douglas, Jackson, Josephine, Klamath, Lane, and Linn counties in Oregon (J. M. Gillett 1972). It has some of the largest leaves of any species of Trifolium in North America.

(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. 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. 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. 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. bifidum var. decipiens, T. greenei, T. hallii
Name authority A. Gray: Proc. Calif. Acad. Sci. 3: 102. (1864) S. Watson: Proc. Amer. Acad. Arts 23: 262. (1888)
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