woolly-head clover
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marshmallow clover, Piorkowski's clover
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Herbs perennial, 12–46 cm, sparsely hairy to densely villous, appressed-pubescent, or glabrate. |
Herbs annual, 7–30 cm, glabrous. |
erect or decumbent, branched. |
erect or ascending, sparsely to much branched. |
palmate; stipules lanceolate or ovate, 1–5 cm, margins entire or denticulate, apex acuminate or acute; petiole 1–15 cm; petiolules 1 mm; leaflets 3, blades linear, linear-elliptic, elliptic, lanceolate, lanceolate-oblong, or obovate, 1–5 × 0.4–1.2 cm, base cuneate, veins fine or ± thickened, margins denticulate or serrulate, apex acuminate or acute, surfaces appressed-pubescent abaxially, glabrous, densely villous, or sparsely or densely pilose adaxially. |
palmate; stipules ovate-lanceolate, 1–1.5 cm, margins entire, apex acute-acuminate; petiole 8–12 cm; petiolules 1 mm; leaflets 3, blades oblanceolate or obovate, 2.8 × 1.9 cm, base cuneate, veins delicate, margins entire or shallowly dentate distally, lateral veins sometimes ending in a bristle, apex rounded to acute, surfaces glabrous. |
terminal or axillary, 25–70-flowered, inverted or horizontal, ellipsoid or globose to subglobose, 2–3 × 1–3 cm, rachis prolonged beyond flowers; involucres absent. |
axillary or terminal, 3–16-flowered, in 1–3 whorls, subglobose, 2–2.8 × 1.8–2.6 cm; involucres bowl-shaped, 6–15 mm, lobes 6–8, broadly lanceolate, margins entire, acuminate, apex 3–5-fid. |
bent distally, proximal to flowers, 3–18 cm. |
5–15 cm. |
reflexed, to 0.3 mm; bracteoles absent. |
straight, 0.5–1 mm; bracteoles absent. |
9–18 mm; calyx campanulate, curved in fruit, 4–11 mm, villous, veins 10, tube 1.5–2.5 mm, lobes unequal, 2–3 times tube, subulate, often strongly curved and twisted, plumose, orifice open; corolla white, cream, or purple, 8–16 mm, banner oblanceolate, 8–16 × 3–5 mm, apex rounded or retuse, recurved; ovaries pubescent distally. |
12–14 mm; calyx campanulate, 5–8 mm, glabrous, veins 10, tube 2.5–4 mm, lobes 11–15, unequal, abaxial 3–5 forked, adaxial unbranched, orifice open; corolla creamy white to pinkish, 11–13 mm, banner ovate, inflated entire length in fruit, not distally twisted, 11–13 × 5–7 mm, apex rounded. |
ovoid, 2–3.5 mm. |
ellipsoid, 5–6 mm. |
(1 or)2–4, yellow-brown to brown, mitten-shaped or subglobose, 1.2–2 mm, smooth. |
1 or 2, gray-brown, black-mottled, subglobose, 2.5 mm, smooth. |
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Flowering Apr–May. |
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Shallow, vernally wet depressions on volcanic flats, banks of watercourses flowing through open rocky grassland, transitional habitats with scattered chaparral and conifers. |
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300–800 m. [1000–2600 ft.] |
w United States
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CA |
Subspecies 6 (6 in the flora). Trifolium eriocephalum was revised by J. M. Gillett (1971). The subspecies exhibit unusually complex distributional patterns, and overlapping morphological features sometimes make identifications problematic (M. Zohary and D. Heller 1984). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Trifolium piorkowskii is known only from Shasta County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
1. Ovules usually 2, rarely 1 or 3; calyx lobes usually green, rarely purple, straight, subequal, 3–4 timestube. | → 2 |
2. Herbs densely villous; leaflet blades of basal and median leaves elliptic or lanceolate-oblong; roots cylindric, thickened. | subsp. eriocephalum |
2. Herbs slightly villous, appressed-pubescent, or glabrate; leaflet blades of basal and median leaves usually narrowly lanceolate or linear, rarely narrowly elliptic; roots fusiform-tuberous. | subsp. cascadense |
1. Ovules 3 or 4; calyx lobes usually purple, contorted, abaxial lobes longer, lateral lobes 1–1.5 times tube. | → 3 |
3. Leaflet blades of basal leaves linear or linear-elliptic, apex acute, surfaces sparsely or densely hairy adaxially; roots cylindric, thickened, branched, often rhizomelike. | → 4 |
4. Blades of leaflets of median leaves linear or linear-elliptic; herbs slightly villous. | subsp. cusickii |
4. Blades of leaflets of median leaves broadly elliptic; herbs densely villous. | subsp. villiferum |
3. Leaflet blades of basal leaves obovate, apex rounded to retuse, surfaces usually glabrous adaxially, sometimes sparsely hairy; roots fusiform-tuberous. | → 5 |
5. Inflorescences 2.5 cm diam., significantly overtopping distal leaves; leaflet blades of median leaves broadly lanceolate, surfaces sparsely hairy or glabrous adaxially. | subsp. arcuatum |
5. Inflorescences 1 cm diam., scarcely overtopping distal leaves; leaflet blades of median leaves narrowly lanceolate or linear, surfaces densely villous adaxially. | subsp. martinii |
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FNA vol. 11. |
FNA vol. 11. |
Fabaceae > subfam. Faboideae > Trifolium |
Fabaceae > subfam. Faboideae > Trifolium |
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. 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. 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. 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 |
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Nuttall in J. Torrey and A. Gray: Fl. N. Amer. 1: 313. (1838) |
Rand. Morgan & A. L. Barber: Novon, 23: 65, plate 1. (2014) |
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