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Thompson's buckwheat, Thompson's wild buckwheat

frosted buckwheat, frosted wild buckwheat

Habit Herbs, spreading, not scapose, 2–5(–6) × 2–5 dm, glabrous, green. Herbs, matted, dioecious, 0.5–3 × 1–4 dm wide, tomentose to floccose.
Stems

spreading, without persistent leaf bases, up to 1/5 height of plant;

caudex stems spreading, glabrous;

aerial flowering stems erect, slender, solid, not fistulose, 1.2–3 dm, glabrous, tomentose among leaves.

caudex spreading;

aerial flowering stems erect or nearly so, slender, solid, not fistulose, arising at nodes of caudex branches and at distal nodes of short, nonflowering aerial branches, 0.1–2(–2.5) dm, tomentose to floccose.

Leaves

basal or sheathing up stem less than 2 cm, 1 per node;

petiole (0.1–)3–7(–10) cm, tomentose to floccose or glabrous;

blade linear or oblong to oblanceolate or elliptic, 2–8(–10) × 0.2–2.5(–3) cm, thinly to densely white-tomentose abaxially, glabrous and green adaxially, margins plane or slightly revolute.

in loose to congested basal rosettes;

petiole (0.3–)0.5–1 cm, tomentose;

blade oblong to oblong-ovate or spatulate, 0.5–1.5 × 0.3–0.7 cm, densely white- or grayish-tomentose on both surfaces, sometimes greenish adaxially, margins entire, plane.

Inflorescences

cymose, open, 10–30 × 10–25 cm;

branches dichotomous, glabrous;

bracts 3, scalelike, linear, 2–5(–7) mm.

capitate and 0.5–2 cm wide, mature pistillate plants open and umbellate, 1–3 × 1–4 cm;

branches tomentose to floccose;

bracts 2–6, leaflike, 0.1–0.5 × 0.1–0.3 cm, often absent immediately below involucre.

Peduncles

absent.

Involucres

1 per node, turbinate, 2–3(–3.5) × 1–1.5(–2) mm, glabrous;

teeth 5, erect, 0.4–0.5 mm.

1 per node but occasionally appearing congested, turbinate-campanulate, 2.5–3 × 2–2.5 mm, tomentose;

teeth 5–8, erect, 0.5–1 mm.

Flowers

3–3.5 mm;

perianth yellow or white, glabrous;

tepals connate only at base, monomorphic, oblong to obovate;

stamens slightly exserted, 3–3.5(–4) mm;

filaments sparsely pilose proximally.

stipelike base 0.5–1 mm;

perianth yellow, glabrous;

staminate flowers 2–3 mm, tepals ovate;

pistillate flowers 4–6 mm, tepals oblanceolate, often becoming reddish in fruit;

stamens exserted, 2–3 mm;

filaments pilose proximally.

Achenes

light brown to brown, 2.5–3 mm, glabrous except for slightly papillate beak.

light brown to brown, 3–3.5 mm, glabrous except for sparsely pubescent beak.

Eriogonum thompsoniae

Eriogonum incanum

Phenology Flowering Jun–Sep.
Habitat Sandy to gravelly or rocky granitic or occasionally volcanic flats, slopes, and outcrops, mixed grassland, manzanita, and sagebrush communities, montane conifer woodlands
Elevation (1900-) 2100-4000 m ((6200-) 6900-13100 ft)
Distribution
from FNA
AZ; UT
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; NV
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 3 (3 in the flora).

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

Eriogonum incanum is common throughout the central and southern Sierra Nevada of California (Alpine, El Dorado, Fresno, Inyo, Madera, Mariposa, Nevada, Tulare, and Tuolumne counties) and extreme west-central Nevada (Carson City, Douglas, and Washoe counties). It is a food plant for the green hairstreak butterfly (Callophrys lemberti), the Pacific dotted-blue (Euphilotes enoptes), and the gorgon copper (Gaeides gorgon).

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

Key
1. Leaf blades linear, 3-8(-10) × 0.2-0.4(-0.6) cm
var. atwoodii
1. Leaf blades oblong to oblanceolate or elliptic; 2-5 × 0.8-2.5(-3) cm
→ 2
2. Perianths yellow
var. thompsoniae
2. Perianths white
var. albiflorum
Source FNA vol. 5, p. 261. FNA vol. 5, p. 366.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Oligogonum
Sibling taxa
E. abertianum, E. acaule, E. alatum, E. aliquantum, E. allenii, E. alpinum, E. ammophilum, E. ampullaceum, E. androsaceum, E. anemophilum, E. angulosum, E. annuum, E. apiculatum, E. apricum, E. arborescens, E. arcuatum, E. aretioides, E. argillosum, E. argophyllum, E. arizonicum, E. artificis, E. atrorubens, E. baileyi, E. batemanii, E. bicolor, E. bifurcatum, E. brachyanthum, E. brachypodum, E. brandegeei, E. breedlovei, E. brevicaule, E. butterworthianum, E. caespitosum, E. capillare, E. cernuum, E. chrysops, E. cinereum, E. cithariforme, E. clavatum, E. clavellatum, E. codium, E. collinum, E. coloradense, E. compositum, E. concinnum, E. congdonii, E. contiguum, E. contortum, E. correllii, E. corymbosum, E. covilleanum, E. crocatum, E. cronquistii, E. crosbyae, E. cusickii, E. darrovii, E. dasyanthemum, E. davidsonii, E. deflexum, E. deserticola, E. desertorum, E. diatomaceum, E. diclinum, E. divaricatum, E. douglasii, E. eastwoodianum, E. effusum, E. elatum, E. elegans, E. elongatum, E. ephedroides, E. eremicola, E. eremicum, E. ericifolium, E. esmeraldense, E. evanidum, E. exaltatum, E. exilifolium, E. fasciculatum, E. flavum, E. fusiforme, E. giganteum, E. gilmanii, E. glandulosum, E. gordonii, E. gossypinum, E. gracile, E. gracilipes, E. gracillimum, E. grande, E. greggii, E. gypsophilum, E. havardii, E. heermannii, E. helichrysoides, E. hemipterum, E. heracleoides, E. hieracifolium, E. hirtellum, E. hirtiflorum, E. hoffmannii, E. holmgrenii, E. hookeri, E. howellianum, E. hylophilum, E. incanum, E. inerme, E. inflatum, E. intrafractum, E. jamesii, E. jonesii, E. kelloggii, E. kennedyi, E. kingii, E. lachnogynum, E. lancifolium, E. latens, E. latifolium, E. lemmonii, E. leptocladon, E. leptophyllum, E. libertini, E. lobbii, E. loganum, E. lonchophyllum, E. longifolium, E. luteolum, E. maculatum, E. mancum, E. marifolium, E. mensicola, E. microthecum, E. mitophyllum, E. mohavense, E. molestum, E. mortonianum, E. multiflorum, E. natum, E. nealleyi, E. nervulosum, E. nidularium, E. niveum, E. nortonii, E. novonudum, E. nudum, E. nummulare, E. nutans, E. ochrocephalum, E. ordii, E. ostlundii, E. ovalifolium, E. palmerianum, E. panamintense, E. panguicense, E. parishii, E. parvifolium, E. pauciflorum, E. pelinophilum, E. pendulum, E. pharnaceoides, E. plumatella, E. polycladon, E. polypodum, E. prattenianum, E. prociduum, E. pulchrum, E. pusillum, E. pyrolifolium, E. racemosum, E. reniforme, E. ripleyi, E. rixfordii, E. robustum, E. rosense, E. roseum, E. rotundifolium, E. rubricaule, E. rupinum, E. salicornioides, E. saxatile, E. scabrellum, E. scopulorum, E. shockleyi, E. siskiyouense, E. smithii, E. soliceps, E. soredium, E. spathulatum, E. spectabile, E. spergulinum, E. sphaerocephalum, E. strictum, E. subreniforme, E. suffruticosum, E. temblorense, E. tenellum, E. ternatum, E. terrenatum, E. thomasii, E. thornei, E. thurberi, E. thymoides, E. tiehmii, E. tomentosum, E. trichopes, E. tripodum, E. truncatum, E. tumulosum, E. twisselmannii, E. umbellatum, E. ursinum, E. vestitum, E. villiflorum, E. vimineum, E. viridescens, E. viridulum, E. viscidulum, E. visheri, E. watsonii, E. wetherillii, E. wootonii, E. wrightii, E. zionis
E. abertianum, E. acaule, E. alatum, E. aliquantum, E. allenii, E. alpinum, E. ammophilum, E. ampullaceum, E. androsaceum, E. anemophilum, E. angulosum, E. annuum, E. apiculatum, E. apricum, E. arborescens, E. arcuatum, E. aretioides, E. argillosum, E. argophyllum, E. arizonicum, E. artificis, E. atrorubens, E. baileyi, E. batemanii, E. bicolor, E. bifurcatum, E. brachyanthum, E. brachypodum, E. brandegeei, E. breedlovei, E. brevicaule, E. butterworthianum, E. caespitosum, E. capillare, E. cernuum, E. chrysops, E. cinereum, E. cithariforme, E. clavatum, E. clavellatum, E. codium, E. collinum, E. coloradense, E. compositum, E. concinnum, E. congdonii, E. contiguum, E. contortum, E. correllii, E. corymbosum, E. covilleanum, E. crocatum, E. cronquistii, E. crosbyae, E. cusickii, E. darrovii, E. dasyanthemum, E. davidsonii, E. deflexum, E. deserticola, E. desertorum, E. diatomaceum, E. diclinum, E. divaricatum, E. douglasii, E. eastwoodianum, E. effusum, E. elatum, E. elegans, E. elongatum, E. ephedroides, E. eremicola, E. eremicum, E. ericifolium, E. esmeraldense, E. evanidum, E. exaltatum, E. exilifolium, E. fasciculatum, E. flavum, E. fusiforme, E. giganteum, E. gilmanii, E. glandulosum, E. gordonii, E. gossypinum, E. gracile, E. gracilipes, E. gracillimum, E. grande, E. greggii, E. gypsophilum, E. havardii, E. heermannii, E. helichrysoides, E. hemipterum, E. heracleoides, E. hieracifolium, E. hirtellum, E. hirtiflorum, E. hoffmannii, E. holmgrenii, E. hookeri, E. howellianum, E. hylophilum, E. inerme, E. inflatum, E. intrafractum, E. jamesii, E. jonesii, E. kelloggii, E. kennedyi, E. kingii, E. lachnogynum, E. lancifolium, E. latens, E. latifolium, E. lemmonii, E. leptocladon, E. leptophyllum, E. libertini, E. lobbii, E. loganum, E. lonchophyllum, E. longifolium, E. luteolum, E. maculatum, E. mancum, E. marifolium, E. mensicola, E. microthecum, E. mitophyllum, E. mohavense, E. molestum, E. mortonianum, E. multiflorum, E. natum, E. nealleyi, E. nervulosum, E. nidularium, E. niveum, E. nortonii, E. novonudum, E. nudum, E. nummulare, E. nutans, E. ochrocephalum, E. ordii, E. ostlundii, E. ovalifolium, E. palmerianum, E. panamintense, E. panguicense, E. parishii, E. parvifolium, E. pauciflorum, E. pelinophilum, E. pendulum, E. pharnaceoides, E. plumatella, E. polycladon, E. polypodum, E. prattenianum, E. prociduum, E. pulchrum, E. pusillum, E. pyrolifolium, E. racemosum, E. reniforme, E. ripleyi, E. rixfordii, E. robustum, E. rosense, E. roseum, E. rotundifolium, E. rubricaule, E. rupinum, E. salicornioides, E. saxatile, E. scabrellum, E. scopulorum, E. shockleyi, E. siskiyouense, E. smithii, E. soliceps, E. soredium, E. spathulatum, E. spectabile, E. spergulinum, E. sphaerocephalum, E. strictum, E. subreniforme, E. suffruticosum, E. temblorense, E. tenellum, E. ternatum, E. terrenatum, E. thomasii, E. thompsoniae, E. thornei, E. thurberi, E. thymoides, E. tiehmii, E. tomentosum, E. trichopes, E. tripodum, E. truncatum, E. tumulosum, E. twisselmannii, E. umbellatum, E. ursinum, E. vestitum, E. villiflorum, E. vimineum, E. viridescens, E. viridulum, E. viscidulum, E. visheri, E. watsonii, E. wetherillii, E. wootonii, E. wrightii, E. zionis
Subordinate taxa
E. thompsoniae var. albiflorum, E. thompsoniae var. atwoodii, E. thompsoniae var. thompsoniae
Synonyms E. corymbosum var. thompsoniae E. marifolium var. incanum, E. ursinum var. rosulatum
Name authority S. Watson: Amer. Naturalist 7: 302. (1873) Torrey & A. Gray: Proc. Amer. Acad. Arts 8: 161. (1870)
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