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red clover

carpet clover, mountain carpet clover

Habit Herbs perennial, 20–70 cm, pilose or glabrous. Herbs perennial, 3–22 cm, glabrous or hairy, often mat-forming.
Stems

erect, ascending, or decumbent, branched.

decumbent to ascending, much-branched.

Leaves

palmate;

stipules broadly triangular, 1–2 cm, margins entire, sometimes ciliate, apex mucronate or setaceous;

petiole 1–9 cm;

petiolules 1 mm;

leaflets 3, blades elliptic to obovate, 1.5–5 × 0.7–1.5 cm, base cuneate, veins prominent, margins subentire, apex obtuse, acute, or retuse, surfaces appressed-pubescent.

palmate;

stipules ovate to lanceolate, 0.3–1.2 cm, margins entire, serrate, or slightly lacerate, apex acute to acuminate;

petiole 1–4.5 cm;

petiolules 0.1–0.5 mm;

leaflets 3, blades obovate, oblanceolate, or elliptic, 0.3–2 × 0.2–0.5 cm, base cuneate, veins prominent, margins ± dentate, serrate, or setose, apex acute, rounded, or retuse, surfaces glabrous or slightly villous.

Inflorescences

terminal, solitary or paired, 75–100+-flowered, globose or ovoid, 1.2–7.7 × 0.7–2.2 cm;

involucres absent, involucrelike structures formed of stipules of distalmost leaves.

axillary or terminal, 1–9-flowered, solitary or subglobose, 1–1.6 × 0.3–1.2 cm;

involucres campanulate, 2–5 mm, incised nearly to base, lobes 2–8, lanceolate.

Peduncles

± 0 cm, subtended by stipules of distal leaves.

0.5–2 cm.

Pedicels

straight, 0–1 mm;

bracteoles absent.

erect, 1 mm;

bracteoles absent.

Flowers

15–18 mm;

calyx tubular-campanulate, 8–11 mm, hairy, veins 10, tube 3–4 mm, lobes unequal, adaxial equaling tube, lateral and abaxial 2 times tube, orifice hairy, slightly closed;

corolla usually rose-purple, rarely pink or white, 13–18 mm, banner elliptic-ovate, 10–13 × 3–5 mm, apex narrowly rounded.

10–16 mm;

calyx tubular, 2–10 mm, glabrous or pubescent, veins 10, tube 4–7 mm, lobes equal, triangular-subulate, orifice open;

corolla white, pink, or lavender, keel petals usually purple-spotted, 8–16 mm, banner oblong, 8–13 × 2–5 mm, apex emarginate.

Legumes

oblong, leathery distally, transversely dehiscent, 3 mm.

oblong, 2–4 mm.

Seeds

1 or 2, yellow, yellow-brown, or purple, ovoid, 1.6–2 mm, smooth, dull.

1 or 2, brown, mottled, mitten-shaped, 1–2 mm, dull.

2n

= 14.

= 16.

Trifolium pratense

Trifolium monanthum

Phenology Flowering May–Sep.
Habitat Fields, prairies, roadsides, disturbed areas.
Elevation 0–3100 m. (0–10200 ft.)
Distribution
from FNA
AK; AL; AR; AZ; CA; CO; 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; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; NT; ON; PE; QC; SK; YT; SPM; Greenland; Eurasia [Introduced in North America; introduced also in s South America, s Africa, Pacific Islands (Hawaii, New Zealand), Australia]
[WildflowerSearch map]
[BONAP county map]
from USDA
w United States; nw Mexico
[WildflowerSearch map]
[BONAP county map]
Discussion

Trifolium pratense is morphologically variable and numerous varieties have been recognized (M. Zohary and D. Heller 1984). Distinctions among these are slight and intergradation is common, perhaps due to the long-time cultivation of the species. In North America, the following varieties are sometimes recognized: var. pratense with stems decumbent to ascending, 20–40 cm, with dense, appressed, white hairs; var. sativum Schreber with stems mostly erect, 40–100 cm, sparsely hairy or glabrous; and var. americanum Harz with stems 30–100 cm, with dense, spreading hairs.

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

Subspecies 4 (4 in the flora).

Morphological intergradation among subspecies of Trifolium monanthum may be indicative of low genetic barriers to crossing. It might be just as plausible to divide T. mononathum into two species instead of four subspecies (J. M. Gillett 1980), with T. monanthum encompassing populations with white rhizomes, and T. multicaule encompassing populations with taproots.

Trifolium monanthum often forms dense mats.

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

Key
1. Herbs glabrous or sparsely hairy, mat-forming; stems from thin to thick woody roots, rhizomes slender, white; peduncles straight or bent upwards at steep angle distally; flowers 1–5.
→ 2
2. Inflorescences (1 or)2–4-flowered; peduncles straight; leaflet blades obovate to oblanceo­late, margins ± dentate, apex rounded or retuse.
subsp. monanthum
2. Inflorescences 1–5-flowered; peduncles bent upwards at steep angle distally; leaflet blades oblanceolate or elliptic, margins setose, apex acute.
subsp. grantianum
1. Herbs densely hairy, decumbent to ascending; stems from thickened woody taproots, rhizomes absent; peduncles bent upwards at steep angle distally; flowers 1–9.
→ 3
3. Leaflet blade apex rounded, margins dentate.
subsp. parvum
3. Leaflet blade apex acute, margins serrate or setose.
subsp. tenerum
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. 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. 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. 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
Subordinate taxa
T. monanthum subsp. grantianum, T. monanthum subsp. monanthum, T. monanthum subsp. parvum, T. monanthum subsp. tenerum
Synonyms T. pensylvanicum
Name authority Linnaeus: Sp. Pl. 2: 768. (1753) A. Gray: Proc. Amer. Acad. Arts 6: 523. (1865)
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