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knotted clover

Rocky Mountain clover

Habit Herbs usually annual, rarely biennial, 10–50 cm, villous. Herbs perennial, 5–30 cm, pubescent.
Stems

erect, ascending, or decumbent, branched from base.

erect or ascending, cespitose, branched from base, numerous short stems.

Leaves

palmate;

stipules lanceolate-ovate, 0.9–1.1 cm, margins entire, apex acute-acuminate, setaceous, ciliate;

petiole 0.5–5 cm;

petiolules 0.5 mm;

leaflets 3, blades obovate to oblong, 0.9–1.6 × 0.4–1 cm, base cuneate, veins fine, margins denticulate, apex obtuse, obcordate, or emarginate, surfaces hairy.

palmate;

stipules lanceolate, 1.8–2 cm, margins entire, apex acute-acuminate;

petiole 2.5–10 cm;

petiolules to 0.5 mm;

leaflets 3, blades linear, lanceolate, or narrowly elliptic, 1.5–6 × 0.3–1 cm, base cuneate, veins moderately thickened, margins entire, apex acuminate or narrowly acute, surfaces glabrous or pubescent.

Inflorescences

axillary or terminal, solitary or paired, 20–60-flowered, ovoid or oblong, 0.8–1.6 × 0.6–1 cm;

involucres absent.

axillary or terminal, 10–20+-flowered, globose, 2.3–3.5 × 2.5–4 cm;

involucres formed of proximal bracteoles, bases sometimes connate.

Peduncles

0–1 cm.

2–28 cm.

Pedicels

absent;

bracteoles absent.

reflexed in fruit, 2–4 mm;

bracteoles ovate, 2–4 mm, truncate or acuminate.

Flowers

5–7 mm;

calyx ellipsoid to urceolate, 3–4 mm, hairy, veins 10, tube 2–3 mm, lobes erect or spreading, unequal, abaxial longest and equal to tube, subulate, orifice open;

corolla pink, 25–35 mm, banner oblong, 2.5–3.5 × 1.5–2 mm, apex retuse.

15–22 mm;

calyx campanulate, 8–15 mm, pubescent, veins 10, tube 2.5–7 mm, lobes unequal, subulate, orifice open;

corolla red-purple, 16–20 mm, banner broadly oblong-elliptic, 16–20 × 6–7 mm, apex acute, apiculate.

Legumes

ovoid, leathery distally, transversely dehiscent, 2–2.5 mm.

oblong, 5–6 mm.

Seeds

1, tan or reddish brown, globose to ovoid, 1–1.5 mm, smooth, glossy.

1–3, brown, ovoid-reniform, 2.5 mm, smooth.

2n

= 14.

= 16, 48.

Trifolium striatum

Trifolium attenuatum

Phenology Flowering May–Aug. Flowering Jun–Aug.
Habitat Waste places Subalpine and alpine slopes, open montane forests.
Elevation 0–500 m. (0–1600 ft.) 3000–3800 m. (9800–12500 ft.)
Distribution
from FNA
AL; AR; CA; GA; MA; MO; NC; NJ; NY; OK; OR; PA; SC; VA; VT; WA; BC; Europe; w Asia; nw Africa [Introduced also in s South America (Chile), Pacific Islands (New Zealand), Australia]
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; NM
[WildflowerSearch map]
[BONAP county map]
Discussion

Trifolium striatum has been recorded as an occasional weed in the flora area, having been first collected on ballast in New Jersey in 1880. It is found sporadically as a weed of disturbed habitats and appears to be spreading rapidly. It has been called Pitts’s clover in the southern United States because it was discovered by J. D. Pitts in a field of crimson clover as a weed and he experimented with it as a forage plant (G. L. Fuller and B. H. Hendrickson 1928).

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

Trifolium attenuatum ranges from Park County in Colorado southward through southern and southwestern Colorado to northern and central New Mexico.

J. M. Gillett (1965) found both diploid and hexaploid populations of Trifolium attenuatum but was unable to find morphological distinctions between diploid and hexaploid individuals. Using flavonoid chemotaxonomy, E. V. Parups et al. (1966) found close associations between T. attenuatum, T. brandegeei, and T. haydenii.

Trifolium lilacinum Rydberg (1901), which pertains here, is a later homonym of T. lilacinum Greene (1896) and thus illegitimate.

(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. 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. 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. 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. 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. bracteolatum, T. petraeum, T. stenolobum
Name authority Linnaeus: Sp. Pl. 2: 770. (1753) Greene: Pittonia 4: 137. (1900)
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