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Douglas' clover

Pacific grove clover, woods or Pacific grove clover

Habit Herbs perennial, 20–75 cm, glabrous or slightly pilose. Herbs annual, 10–60 cm, glabrous.
Stems

erect, unbranched or sparsely branched.

decumbent or ascending, branched.

Leaves

palmate;

stipules lanceolate to ovate, 1.5–6.5 cm, margins setose-serrulate or entire, apex acuminate;

petiole 1.5–15 cm;

petiolules 1 mm;

leaflets 3, blades elliptic-oblanceolate to linear-elliptic, 3–9.5 × 0.5–1.6 cm, base cuneate, lateral veins prominent, recurved, dichotomously forked near margin, margins setose-denticulate to serrate, apex rounded or acute, surfaces glaucous, glabrous, sometimes sparsely pubescent abaxially.

palmate;

stipules lanceolate to ovate, 0.4–1.8 cm, margins lacerate, apex acute to acuminate;

petiole 0.5–6 cm;

petiolules to 1 mm;

leaflets 3, blades broadly elliptic to broadly obovate, 0.4–2.5 × 0.4–1.5 cm, base cuneate, veins moderately thickened, margins dentate-serrulate, apex rounded or truncate, often retuse, surfaces glabrous.

Inflorescences

terminal or axillary, 30–50+-flowered, umbellate, globose to ovoid, 1.5–5 × 2–3.5 cm;

involucres absent.

axillary, 10–25-flowered, subglobose or globose, 1–1.8 × 1–1.8 cm;

involucres flattened or bowl-shaped, 4–7 mm, incised 1/2 their length, when folded, not hiding flowers except proximally, lobes 5–12, dentate-lacerate, spinulose.

Peduncles

3–12 cm.

1–2 cm.

Pedicels

erect or slightly reflexed, to 0.2 mm;

bracteoles minute.

straight, to 1 mm;

bracteoles absent.

Flowers

14–16 mm;

calyx campanulate, 6–9 mm, pilose, veins 15–20, tube 1.5–3 mm, lobes unequal, narrow, triangular or subulate, abaxial lobe straight, lateral and adaxial tortuous, recurved inwards around corolla, orifice open;

corolla magenta, 12–16 mm, banner oblong, 12–16 × 4–6 mm, apex flared, acute or obtuse;

ovaries glabrous or pubescent distally.

8–10 mm;

calyx campanulate-tubular, not slit between adaxial lobes, 5–7 mm, glabrous, veins 20, tube 1.9–2.4 mm, lobes unequal, 3-fid or laciniate, often appearing 7+-lobed, orifice open;

corolla pink or pale purple, 8–9 mm, banner elliptic, 8–9 × 2–3 mm, apex retuse.

Legumes

ovoid, 3–4.5 mm.

ellipsoid, 3.5–4 mm.

Seeds

1 or 2, tan to brown, ovoid, 1–1.5 mm, slightly roughened.

2, dark brown, mottled, ovoid or reniform, 1.7–1.9 mm, smooth.

2n

= 16.

Trifolium douglasii

Trifolium polyodon

Phenology Flowering Jun–Jul. Flowering Apr–Jun.
Habitat Moist meadows, rich soils in prairies, stream bottoms and banks, openings in pine forests. Along streams, moist meadows.
Elevation 600–1500 m. (2000–4900 ft.) 0–150 m. (0–500 ft.)
Distribution
from FNA
ID; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[BONAP county map]
Discussion

Trifolium douglasii is rare throughout its range and has been impacted by agricultural practices (P. Camp et al. 2011).

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

The taxonomic status of Trifolium polyodon, known only from Monterey County, has long been debated. W. L. Jepson (1936) considered it a variety of T. tridentatum Lindley (= T. willdenovii). The first to consider it as a variety of T. variegatum was J. S. Martin (1943), who never formally published a new combination; an invalid combination was made by M. Zohary and D. Heller (1984). D. Isely (1998) included it in his interpretation of T. variegatum as phase 5 of that species; he speculated that T. polyodon might have originated as a hybrid of T. variegatum and T. willdenovii. Molecular studies (N. W. Ellison et al. 2006) showed that T. polyodon is closely related to T. variegatum but is distinct; it also appears to be related to T. cyathiferum.

(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. 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. palmeri, T. parryi, T. pinetorum, T. piorkowskii, T. plumosum, 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. altissimum T. tridentatum var. polyodon
Name authority House: Bot. Gaz. 41: 335. (1906) Greene: Pittonia 3: 215. (1897)
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