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canyon clover, Howell's clover

plumed clover

Habit Herbs perennial, 30–100 cm, glabrous. Herbs perennial, 10–60 cm, villous.
Stems

erect, fistulose, unbranched or branched distally.

erect, branched or unbranched.

Leaves

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.

palmate;

stipules linear, oblong, or ovate, 1.5–2.5 cm, margins entire or slightly serrulate, apex acute to acuminate;

petiole 1–20 cm;

petiolules to 0.5 mm;

leaflets 3, blades linear, elliptic, oblong, or lanceolate-elliptic, often folded, falcate, 4–11 × 0.1–1.6 cm, base cuneate, veins thickened, margins denticulate, apex acute or acuminate, surfaces villous.

Inflorescences

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.

terminal, 70–80-flowered, spicate, ovoid to cylindric, 3–6 × 2.5–3 cm;

involucres absent.

Peduncles

3–11 cm.

2–6 cm.

Pedicels

strongly reflexed in fruit, 1 mm;

bracteoles minute, blunt or acute, membranous.

erect or absent, 0–0.5 mm;

bracteoles absent.

Flowers

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.

17–18 mm;

calyx campanulate, 5 mm, villous, veins 20, tube 2.5 mm, lobes subequal, subulate, straight, orifice open;

corolla creamy white, keel petals crimson, 12–22 mm, banner oblong, 12–22 × 3–5 mm, apex acute;

ovaries glabrous or pubescent distally.

Legumes

oblong or clavate, 4–5 mm.

obovoid, 4–5 mm.

Seeds

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

1–3, reddish brown or tan, ellipsoid, 1.8–2 mm, smooth, glossy.

2n

= 32.

Trifolium howellii

Trifolium plumosum

Phenology Flowering Jun–Jul.
Habitat Wet stream banks, wet meadows, flood plains, shady woodlands, springs, thickets.
Elevation 800–2000 m. (2600–6600 ft.)
Distribution
from FNA
CA; OR
[WildflowerSearch map]
[BONAP county map]
from USDA
nw United States
[WildflowerSearch map]
[BONAP county map]
Discussion

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.)

Subspecies 2 (2 in the flora).

J. M. Gillett (1972) stated that the leaflet width in the basal leaves is the best distinction between the two subspecies, which are geographically isolated.

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

Key
1. Leaflet blades of basal leaves 0.2–0.5(–0.7) cm wide, apex acuminate; herbs 20–35 cm.
subsp. plumosum
1. Leaflet blades of basal leaves (0.8–)0.9–1.6 cm wide, apex acute; herbs 10–60 cm.
subsp. amplifolium
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. 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
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. 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
Subordinate taxa
T. plumosum subsp. amplifolium, T. plumosum subsp. plumosum
Name authority S. Watson: Proc. Amer. Acad. Arts 23: 262. (1888) Douglas in W. J. Hooker: Fl. Bor.-Amer. 1: 130, plate 49. (1831)
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