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Douglas' clover

Siskiyou clover

Habit Herbs perennial, 20–75 cm, glabrous or slightly pilose. Herbs perennial, 20–50 cm, glabrous; rhizomes elongate, slender, roots tuberous.
Stems

erect, unbranched or sparsely branched.

erect, sparsely 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, 0.8–1.5 cm, margins entire or slightly lacerate, apex acuminate;

petiole 1.6–2.4 cm;

petiolules 0.5 mm;

leaflets 3, blades obovate, oblanceolate, or elliptic, 0.8–3 × 0.5–0.7 cm, base cuneate, veins fine or thickened distally, margins finely serrulate, apex acute, mucronate, or retuse, surfaces glabrous.

Inflorescences

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

involucres absent.

usually terminal, sometimes axillary, 30–50-flowered, subglobose, 1.2–1.8 × 1.5–2 cm;

involucres shallowly bowl-shaped, 18–22 mm, deeply incised, lobes slender, irregular or bifurcate.

Peduncles

3–12 cm.

2.8–3.4 cm.

Pedicels

erect or slightly reflexed, to 0.2 mm;

bracteoles minute.

straight, 0.5–0.8 mm;

bracteoles linear, 1–2 mm.

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.

10–13 mm;

calyx tubular, 0.5–0.6 mm, glabrous, veins 10, tube 2 mm, lobes ± equal, 3–4 mm, orifice open;

corolla white to purple, 9–12 mm, banner oblong, 7–12 × 2–3 mm, apex retuse.

Legumes

ovoid, 3–4.5 mm.

oblong, 2–4 mm.

Seeds

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

2–4, brown, subglobose or mitten-shaped, 1.5 mm, smooth.

2n

= 16.

Trifolium douglasii

Trifolium siskiyouense

Phenology Flowering Jun–Jul. Flowering Jun–Jul.
Habitat Moist meadows, rich soils in prairies, stream bottoms and banks, openings in pine forests. Wet meadows, grassy hillsides.
Elevation 600–1500 m. (2000–4900 ft.) 1000–1500 m. (3300–4900 ft.)
Distribution
from FNA
ID; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR
[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.)

Trifolium siskiyouense is known from Shasta and Siskiyou counties, California, and Douglas, Jackson, and Josephine counties, Oregon. It is difficult to distinguish from T. wormskioldii without underground parts showing the tubers, but can be separated from the latter by deeply cut involucral segments, long-lobed, slender calyces, and the combination of long wing petals and short keel petals (J. M. Gillett 1980).

(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. polyodon, T. pratense, T. productum, T. reflexum, T. repens, T. resupinatum, T. retusum, T. rollinsii, 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. wormskioldii var. siskiyouense
Name authority House: Bot. Gaz. 41: 335. (1906) J. M. Gillett: Canad. J. Bot. 58: 1441. (1980)
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