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frosted buckwheat, frosted wild buckwheat

Mount Diablo buckwheat, Mt. Diablo buckwheat, Mt. Diablo wild buckwheat

Habit Herbs, matted, dioecious, 0.5–3 × 1–4 dm wide, tomentose to floccose. Herbs, erect, 1–4.5 dm, tomentose to floccose, grayish.
Stems

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.

aerial flowering stems erect or nearly so, (0.1–)0.2–0.6(–0.8) dm, tomen-tose.

Leaves

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.

basal and cauline;

basal: petiole (1–)2–5(–7) cm, floccose, blade narrowly oblong to obovate, 1–5(–7) × (0.5–)1–2(–3) cm, densely grayish-tomen-tose abaxially, floccose to glabrate and greenish adaxially;

cauline: petiole (0.5–)1–2(–3) cm, floccose, blade narrowly oblong, (0.8–)1–3(–6) × 0.2–1(–2) cm, similar to basal blade.

Inflorescences

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.

cymose, open, (5–)10–30(–40) × 5–30 cm;

branches tomentose to floccose;

bracts 0.5–2 × 0.5–1 mm.

Peduncles

absent.

Involucres

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.

terminal at tips of slender branchlets proximally, not appressed to branches, turbinate, 2.5–3.5(–4) × 2–2.5 mm, tomentose;

teeth 5, erect, 0.1–0.3 mm.

Flowers

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.

(1.5–)1.7–2(–2.2) mm;

perianth white to rose, glabrous;

tepals essentially monomorphic, elliptic to oblong or obovate;

stamens included, 1.5–2 mm;

filaments glabrous;

styles 0.2–0.3 mm.

Achenes

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

light brown, 3-gonous, 1.7–2 mm;

beak smooth.

Eriogonum incanum

Eriogonum truncatum

Phenology Flowering Jun–Sep. Flowering Apr–Aug.
Habitat Sandy to gravelly or rocky granitic or occasionally volcanic flats, slopes, and outcrops, mixed grassland, manzanita, and sagebrush communities, montane conifer woodlands Sandy slopes, mixed grassland and chaparral communities, oak woodlands
Elevation (1900-) 2100-4000 m ((6200-) 6900-13100 ft) 200-400 m (700-1300 ft)
Distribution
from FNA
CA; NV
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[BONAP county map]
Discussion

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.)

Of conservation concern.

Eriogonum truncatum is presumed extinct. It is known only from seven collections, most made in the Marsh Creek and Mt. Diablo areas of Contra Costa County. It was found also at Suisun in Solano County (Earle s.n., 3 Aug 1888, DUKE). Three collections are widely distributed in herbaria: M. L. Baker 2833, Marsh Creek, 28 Apr 1903 (B, CAS, F, MICH, MIN, MSC, NY, POM, RM, UC), M. K. Curran s.n., Antioch, May 1886 (CAS, CS, DS, ISC, JEPS, NY, POM, UC), and J. T. Howell 11816, 10 miles from Clayton on Marsh Creek Road, 8 Apr 1934 (CAS, DS, F, MICH, MIN, MO, MONTU, NY, UC, RSA). Eriogonum truncatum may be quickly distinguished from the morphologically similar E. roseum by its consistently dichotomously branched inflorescences, with each new branch curving upward gracefully from the node. The ultimate inflorescence branches of E. roseum are typically composed of several racemosely arranged involucres along a single, elongated branch.

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

Source FNA vol. 5, p. 366. FNA vol. 5, p. 418.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Oligogonum Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Oregonium
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. 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
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. thompsoniae, E. thornei, E. thurberi, E. thymoides, E. tiehmii, E. tomentosum, E. trichopes, E. tripodum, 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
Synonyms E. marifolium var. incanum, E. ursinum var. rosulatum
Name authority Torrey & A. Gray: Proc. Amer. Acad. Arts 8: 161. (1870) Torrey & A. Gray: Proc. Amer. Acad. Arts 8: 173. (1870)
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