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foothill clover, tree clover

least hop clover, lesser hop clover, lesser hop trefoil, little hop clover, shamrock, small hop-clover, suckling clover

Habit Herbs annual, 5–50 cm, glabrous or sparsely hairy. Herbs annual, 20–40 cm, glabrous or sparsely hairy.
Stems

erect, branched.

erect to prostrate, branched from base.

Leaves

palmate;

stipules ovate-lanceolate, 1–1.5 cm, margins entire, sometimes ciliate, apex acuminate;

petiole 1–13 cm;

petiolules 0.5 mm;

leaflets 3, blades elliptic to oblong or obovate, 0.8–3.5 × 0.5–1.5 cm, base cuneate, veins thickened, margins serrate proximally, obscurely denticulate distally, apex usually rounded or retuse, rarely acute, surfaces glabrous.

pinnate;

stipules ovate, 0.3–0.5 cm, margins entire, apex acute;

petiole to 1.5 cm;

lateral leaflet petiolules to 0.5 mm, terminal leaflet stalk 1–1.5 mm;

leaflets 3, blades obovate to elliptic-lanceolate, 1–2 × 0.5–1.5 cm, base cuneate, lateral veins prominent, ± parallel, ascending, margins dentate distally, apex rounded or retuse, surfaces glabrous or sparsely hairy.

Inflorescences

axillary or terminal, 10–30-flowered, ovoid to subglobose, 0.7–2.2 × 0.5–2 cm;

involucres a narrow rim, 0.5 mm, membranous, dentate.

axillary or terminal, 5–20-flowered, ovoid or globose, 0.5–0.9 × 0.6 cm;

involucres absent.

Peduncles

2.5–12 cm.

1–1.5 cm.

Pedicels

erect becoming reflexed, 0.5–6 mm;

bracteoles linear or cup-shaped, to 1 mm.

reflexed, 0.2–0.5 mm;

bracteoles a fringe of red setae.

Flowers

6–13 mm;

calyx broadly campanulate, 5–11 mm, glabrous, veins 10, tube 1–5 mm, lobes unequal, elliptic to linear, margins hyaline, dentate or pectinate, ciliate, sinuses narrow, orifice open;

corolla white, pink, or purple, 5–13 mm, banner broadly ovate, 6–13 × 4–7 mm, apex rounded, apiculate.

2.8–3.5 mm;

calyx campanulate, 1.5–2 mm, glabrous, veins 5, tube 0.8–1 mm, lobes unequal, longer than tube, adaxial 2 shorter, orifice open;

corolla pale yellow becoming brown, 2.6–3.2 mm, not or slightly ribbed, banner persistent, spatulate, 2.6–3.2 × 2 mm, apex rounded to broadly acute.

Legumes

short-stipitate, ovoid, 5–10 mm.

stipitate, ellipsoid, 1.5–2 mm, short beaked.

Seeds

1 or 2, brown, mottled, ovoid, 2.5–3 mm, smooth.

1, yellow or pale brown, ellipsoid, 0.9–1 mm, smooth, glossy.

2n

= 16.

= 16, 28, 32.

Trifolium ciliolatum

Trifolium dubium

Phenology Flowering Apr–Jun. Flowering May–Oct.
Habitat Oak-pine chaparral, meadows, roadsides. Disturbed ground, fields.
Elevation 0–1500 m. (0–4900 ft.) 0–2300 m. (0–7500 ft.)
Distribution
from FNA
CA; OR; WA; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; AL; AR; AZ; CA; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; TN; TX; VA; VT; WA; WI; WV; WY; BC; NB; NS; ON; PE; QC; SPM; c Europe; s Europe; w Asia [Introduced in North America; introduced also in s South America, e Asia (e China), n, s Africa, Pacific Islands (Hawaii, New Zealand), Australia]
[WildflowerSearch map]
[BONAP county map]
Discussion

Trifolium ciliolatum is relatively widespread in California and is found in scattered sites in Baja California, Oregon, and Washington.

Trifolium ciliatum Nuttall (1848), which pertains here, is a later homonym of T. ciliatum E. D. Clarke (1813).

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

Trifolium dubium is often confused with Medicago lupulina Linnaeus; the latter may be distinguished by its toothed stipules, deciduous corollas, and shiny, black fruits. Little hop clover may be the co-called shamrock of Irish folklore (E. C. Nelson 1991; P. S. Wyse Jackson 2014); other candidates include other species of Trifolium or species of Medicago or Oxalis.

(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. 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. 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
Synonyms T. ciliatum var. discolor Chrysaspis dubia, T. minus
Name authority Bentham: Pl. Hartw., 304. (1849) Sibthorp: Fl. Oxon., 231. (1794)
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