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

Hayden's clover

Habit Herbs annual, 5–40 cm, slightly villous or glabrous. Herbs perennial, 5–10 cm, glabrous.
Stems

erect to ascending, branched.

ascending, cespitose, short-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.

mostly basal, palmate;

stipules lanceolate, 0.4–0.8 cm, margins entire or lobed, apex acute or acuminate;

petiole 1–6 cm;

petiolules to 0.5 mm;

leaflets 3, blades broadly ovate, 0.4–2 × 0.3–1.5 cm, base cuneate, veins thickened distally, ± straight, sometimes arching distally, 0.5+ mm apart, 5–10 pairs of primary veins, margins sharply antrorse-serrate, apex acute, short-apiculate, surfaces glabrous.

Inflorescences

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

involucres absent.

terminal, 5–20-flowered, erect, globose or subglobose, 0.5–1.5 × 0.8–2.5 cm, rachis prolonged beyond flowers, undivided or forked, often bearing sterile flower buds distally;

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

Peduncles

1.5–3.5 cm.

straight distally, proximal to inflorescence, 5–8 cm.

Pedicels

reflexed, 0.7–1.2 mm;

bracteoles a fringe of red setae.

strongly reflexed, 1.5 mm;

bracteoles broadly ovate, truncate, membranous, to 0.5 mm.

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.

13–17 mm;

calyx campanulate, 4.5–6.5 mm, glabrous, veins 10 (5 sometimes faint), tube 2–3 mm, lobes subequal, narrowly triangular-subulate, equaling tube, orifice open;

corolla salmon, buff-pink, or pink, with white or cream tips, 13–17 mm, banner broadly elliptic-oblong, 13–17 × 6–8 mm, apex rounded, retuse or slightly apiculate.

Legumes

stipitate, oblong, 2–2.5 mm.

stipitate, obovoid-oblong, 6–7 mm.

Seeds

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

1–4, brown, lenticular-ovoid, 2.5–3 mm, smooth.

2n

= 14.

= 16.

Trifolium campestre

Trifolium haydenii

Phenology Flowering Jun–Aug. Flowering Jun–Aug.
Habitat Roadsides, fields. Alpine and subalpine slopes.
Elevation 0–1700 m. (0–5600 ft.) 2200–3800 m. (7200–12500 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
ID; MT; WY
[WildflowerSearch map]
[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 haydenii, which is found in east-central Idaho, southwestern Montana, and northwestern Wyoming, appears related to T. kingii, T. productum, and similar species (J. M. Gillett 1972) and is sometimes confused with T. latifolium (Gillett 1969), from which it differs by the absence of hairs.

(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. grayi, T. gymnocarpon, 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. idahoense
Name authority Schreber in G. F. Hoffmann: Deutschl. Fl. 4: 16, plate 253. (1804) Porter in F. V. Hayden: Prelim. Rep. U.S. Geol. Surv. Montana, 480. (1872) — (as haydeni)
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