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big-head clover, large-head clover

woolly-head clover

Habit Herbs perennial, 5–25 cm, villous. Herbs perennial, 12–46 cm, sparsely hairy to densely villous, appressed-pubescent, or glabrate.
Stems

erect or ascending, branched.

erect or decumbent, branched.

Leaves

palmate;

stipules ovate, obovate, or oblong, 1–3 cm, margins entire, irregularly lobed, or serrate, apex acute or acuminate;

petiole 1–14 cm;

petiolules 0.9–1.2 mm;

leaflets (5–)7–9, blades broadly to narrowly obovate, often folded, 1–2.7 × 0.4–1.1 cm, base cuneate, veins thickened, especially distally, margins serrulate, apex rounded or truncate, apiculate, surfaces villous abaxially, sparsely villous to glabrate adaxially.

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.

Inflorescences

terminal, 20–32-flowered, globose or ovoid-ellipsoid, 2.5–8 × 3–7 cm;

involucres absent.

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.

Peduncles

2–8 cm.

bent distally, proximal to flowers, 3–18 cm.

Pedicels

erect, 1–1.5 mm;

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

reflexed, to 0.3 mm;

bracteoles absent.

Flowers

20–30 mm;

calyx campanulate, 10–22 mm, villous, veins 10–15, tube 2.5–4 mm, lobes subequal, subulate, plumose, orifice open;

corolla white, creamy white, or pinkish, keel petals deep pink, 20–28 mm, banner ovate or oblong, 20–28 × 10–13 mm, apex rounded or slightly emarginate.

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.

Legumes

ovoid, 4–5 mm.

ovoid, 2–3.5 mm.

Seeds

1 or 2, yellow or reddish, mitten-shaped to ellipsoid, 2.5–3 mm, smooth.

(1 or)2–4, yellow-brown to brown, mitten-shaped or subglobose, 1.2–2 mm, smooth.

2n

= 32, 48.

Trifolium macrocephalum

Trifolium eriocephalum

Phenology Flowering Apr–Jun.
Habitat Rocky places, hard, compacted clay-gumbo, lava beds, sage-covered slopes, full sun.
Elevation 80–2500 m. (300–8200 ft.)
Distribution
from FNA
CA; ID; NV; OR; WA
[WildflowerSearch map]
[BONAP county map]
from USDA
w United States
[WildflowerSearch map]
[BONAP county map]
Discussion

Trifolium macrocephalum has the largest inflorescences of any clover. Trifolium megacephalum Nuttall (1818) is an illegitimate replacement name for Lupinaster macrocephalum Pursh.

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

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.)

Key
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
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. 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. 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
Subordinate taxa
T. eriocephalum subsp. arcuatum, T. eriocephalum subsp. cascadense, T. eriocephalum subsp. cusickii, T. eriocephalum subsp. eriocephalum, T. eriocephalum subsp. martinii, T. eriocephalum subsp. villiferum
Synonyms Lupinaster macrocephalum
Name authority (Pursh) Poiret in J. Lamarck et al.: Encycl., suppl. 5: 336. (1817) Nuttall in J. Torrey and A. Gray: Fl. N. Amer. 1: 313. (1838)
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