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field clover, hop clover, hop trefoil, low hop-clover, pinnate hop clover

andrews' clover, Gray's clover

Habit Herbs annual, 5–40 cm, slightly villous or glabrous. Herbs annual, 10–40 cm, densely pubescent or glabrate.
Stems

erect to ascending, branched.

erect, branched.

Leaves

pinnate;

stipules ovate-lanceolate, 0.5–0.8 cm, margins entire, glandular, apex acuminate;

petiole 0.3–2 cm;

lateral leaflet petiolules 0.5–0.6 mm, terminal leaflet stalk 3–5 mm;

leaflets 3, blades rhombic to obovate, 0.4–1.5 × 0.4–0.8 cm, base cuneate, lateral veins prominent, ± parallel, ascending, margins denticulate distally, apex truncate or retuse, surfaces strigose adaxially.

palmate;

stipules ovate, 0.5–1.5 cm, margins toothed or lacerate, apex acute-acuminate;

petiole 1–15 cm;

petiolules 1 mm;

leaflets 3, blades elliptic, oblanceolate, or obovate, 2–2.5 × 1–1.5 cm, base cuneate, veins fine, margins dentate-serrate to crenulate, teeth shortly aristate, apex obtuse or broadly acute, surfaces pubescent or glabrate.

Inflorescences

axillary, 30–60-flowered, globose or broadly ovoid, 0.8–1.5 × 0.7–1 cm;

involucres absent.

axillary or terminal, 5–30-flowered, subglobose or globose, 1.8–3 × 2–3 cm;

involucres bowl-shaped, 10–25 mm, lobes 6–16, sharply setaceous-toothed, sinuses shallow.

Peduncles

1.5–3.5 cm.

2–15 cm.

Pedicels

reflexed, 0.7–1.2 mm;

bracteoles a fringe of red setae.

straight, 0.5 mm;

bracteoles absent.

Flowers

4.3–5 mm;

calyx campanulate, strongly bilabiate, 1.3–1.5 mm, glabrous, veins 5, tube 0.3–0.6 mm, lobes unequal, adaxial deltate, very short, lateral and abaxial linear-subulate, each tipped with 1 or 2 stiff hairs, orifice open;

corolla yellow becoming brown, 3.5–6 mm, ribbed, banner persistent, obovate, enveloping other petals, boat-shaped, 4.3–5 × 2.8–3.2 mm, apex broad, acute.

10–17 mm;

calyx campanulate, 6–13 mm, pubescent, veins 5, tube 3–5 mm, lobes unequal, setaceous, abaxial inconspicuously 2- or 3-fid, adaxial unbranched, segments plumose, orifice open;

corolla usually lavender or purple, sometimes purple with white tips, 8–16 mm, banner oblong, proximally inflated in fruit, distally narrowed into twisted tip, 3–5 × 10–13 mm, apex obtuse, truncate, or emarginate.

Legumes

stipitate, oblong, 2–2.5 mm.

stipitate, ovoid-ellipsoid, 2.5–4 mm.

Seeds

1 or 2, yellow, ellipsoid, 1–1.5 mm, smooth, lustrous.

1 or 2, pale brown, mottled, ellipsoid to mitten-shaped, 1.6–2 mm, rugose.

2n

= 14.

Trifolium campestre

Trifolium grayi

Phenology Flowering Jun–Aug. Flowering Apr–Jun.
Habitat Roadsides, fields. Wet meadows, foothill slopes, pine woodlands.
Elevation 0–1700 m. (0–5600 ft.) 0–600 m. (0–2000 ft.)
Distribution
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; NY; OH; OK; OR; PA; RI; SC; TN; TX; VA; VT; WA; WI; WV; WY; BC; NB; NF; NS; ON; PE; QC; SPM; Europe; w Asia; n Africa [Introduced in North America; introduced also in South America, e Asia (China), s Africa, Pacific Islands (Hawaii, New Zealand), Australia]
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[BONAP county map]
Discussion

Trifolium filiforme Linnaeus and T. procumbens Linnaeus are rejected names that were used historically for T. campestre (J. E. Dandy 1958; N. J. Turland et al. 1996).

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

Trifolium grayi, which ranges from San Luis Obispo County in the south to Mendocino County in the north, and eastward into Amador, Sacramento, and Tuolumne counties, has long been considered a variety of T. barbigerum and some authors claim that intermediates between the two species are encountered (J. S. Martin 1943; D. Isely 1998); others state that the two taxa are distinct (L. F. McDermott 1910; M. A Vincent and R. Morgan 1998).

Trifolium andrewsii (A. Gray) A. Heller is an illegitimate superfluous name that pertains here.

(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. 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. 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 Chrysaspis campestris T. barbigerum var. andrewsii, T. barbigerum var. lilacinum, T. lilacinum
Name authority Schreber in G. F. Hoffmann: Deutschl. Fl. 4: 16, plate 253. (1804) Lojacono: Nuovo Giorn. Bot. Ital. 15: 189. (1883)
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