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pin point clover, slender clover

Monterey clover

Habit Herbs annual, 2–60 cm, glabrous. Herbs annual, 5–45 cm, sparsely villous to glabrescent.
Stems

erect or ascending, branched.

prostrate, decumbent, or erect, branched.

Leaves

palmate;

stipules ovate-lanceolate, 0.5–2.5 cm, membranous, margins entire or slightly serrate, apex long-acuminate;

petiole 0.5–9 cm;

petiolules to 0.5 mm;

leaflets 3, blades obovate to obcordate, 0.5–2.5 × 0.2–1.5 cm, base cuneate, veins moderately thickened, margins setose-serrulate, apex rounded, shallowly retuse, surfaces glabrous.

palmate;

stipules ovate, 0.4–1.2 cm, margins serrate-lacerate, apex acuminate;

petiole 1–4 cm;

petiolules 0.5 mm;

leaflets 3, blades obovate, 0.5–1.5 × 0.4–1 cm, base cuneate, veins moderately prominent, margins denticulate, apex truncate, retuse, or mucronulate, surfaces glabrescent.

Inflorescences

axillary or terminal, 10–25-flowered, globose to subglobose, 0.5–2 × 0.5–2 cm, rachis prolonged beyond flowers;

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

axillary or terminal, 2–15-flowered, subglobose, 1.5–1.8 × 0.5–1.5 cm;

involucres flattened or vase-shaped, 1–3 mm, when folded, not hiding flowers except proximally, incised 2/3–3/4 their length, lobes 5–15, linear-lanceolate, entire, acuminate.

Peduncles

1–9 cm.

1.5–4 cm.

Pedicels

becoming dramatically reflexed, 3–4 mm;

bracteoles low, cuplike, membranous, to 0.5 mm.

erect, 1.5 mm;

bracteoles absent.

Flowers

5–7.5 mm;

calyx narrowly campanulate, 4.5–6.5 mm, glabrous, veins 10, tube 2–2.5 mm, lobes unequal, long-triangular, margins green or purple, orifice open;

corolla white, pink, or purple, 5–8 mm, banner ovate, 5–8 × 3–4 mm, apex broadly rounded, retuse or apiculate.

8–11 mm;

calyx campanulate-tubular, not slit between adaxial lobes, 6–9 mm, usually densely pubescent, rarely sparsely so, veins 10, tube 2.5–4.5 mm, lobes unequal, lanceolate-subulate, orifice open;

corolla light purple with darker purple keel petals, 6–10 mm, banner narrowly obovate, 4–5 × 1 mm, apex retuse.

Legumes

ovoid-ellipsoid, 4–6 mm.

sessile, oblong, 5 mm.

Seeds

1 or 2, tan to brown, mitten-shaped, 1.1–1.5 mm, smooth.

3–6(–9), pale brown, mottled purple, globose to mitten-shaped, 0.8–1 mm, smooth to slightly roughened, semiglossy.

2n

= 16.

Trifolium gracilentum

Trifolium trichocalyx

Phenology Flowering Mar–Jun. Flowering Apr–May.
Habitat Open, grassy areas, gravelly ridges, roadsides, adobe slopes, moist places. Sandy, rich soils in open Monterey pine forests, often after fire.
Elevation 50–1200 m. (200–3900 ft.) 0–50 m. (0–200 ft.)
Distribution
from FNA
AZ; CA; NV; OR; WA; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[BONAP county map]
Discussion

Abundance of Trifolium gracilentum increases in response to burns (J. M. DiTomaso et al. 1999).

The record of Trifolium gracilentum from South Carolina is a waif.

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

Trifolium trichocalyx is an extremely rare species known only from Mendocino and Monterey counties. D. I. Axelrod (1982) suggested that T. trichocalyx might have originated as a hybrid between T. microcephalum and T. variegatum, but this is not supported by molecular studies (N. W. Ellison et al. 2006). It appears to be fire-adapted and appeared in large numbers shortly after a fire in 1987 (U.S. Fish and Wildlife Service 2004).

(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. 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. 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. variegatum, T. vesiculosum, T. virginicum, T. willdenovii, T. wormskioldii
Synonyms T. denudatum, T. exile, T. gracilentum var. exile, T. gracilentum var. inconspicuum, T. gracilentum var. reductum, T. inconspicuum T. oliganthum var. trichocalyx
Name authority Torrey & A. Gray: Fl. N. Amer. 1: 316. (1838) A. Heller: Muhlenbergia 1: 55. (1904)
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