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slender buckwheat, slender wild buckwheat

clumping buckwheat, cushion desert wild buckwheat, mat wild buckwheat, Matted buckwheat, Matted wild buckwheat

Habit Subshrubs or shrubs, erect to spreading, not scapose, 0.2–1.5 × (0.6–)1–13(–16) dm, white- to tannish-tomentose, floccose, or glabrous. Herbs, matted, polygamodioecious, (0.1–)0.3–1 × 1–5(–12) dm.
Stems

spreading to erect, typically without persistent leaf bases, up to 1/2 height of plant;

caudex stems absent or spreading;

aerial flowering stems erect to spreading, slender, solid, not fistulose, 0.05–1.5 dm, lanate, tomentose, floccose, subglabrous, or glabrous.

caudex spreading;

aerial flowering stems scapelike, ascending to weakly erect, slender, solid, not fistulose, arising at nodes of caudex branches and at distal nodes of short, nonflowering aerial branches, (0.1–)0.3–0.8(–1) dm, mostly floccose or glabrous, without a whorl of bracts.

Leaves

cauline, 1 per node or fasciculate;

petiole 0.1–0.5 cm, tomentose to floccose or glabrous;

blade usually elliptic, sometimes linear to obovate, 0.3–3.5 × (0.07–)0.1–1.2 cm, tomentose abaxially, less so or glabrous adaxially, margins occasionally revolute.

in compact basal rosettes;

petiole 0.05–0.4(–0.7) cm, usually tomentose;

blade elliptic to obovate or nearly oval, 0.2–1(–1.5) × 0.15–0.4(–0.5) cm, grayish- to whitish-tomentose on both surfaces or less so and greenish adaxially, margins entire, plane.

Inflorescences

cymose, compact, often flat-topped, 0.5–6(–12) × 1–10(–13) cm;

branches dichotomous, whitish-lanate to brownish- or reddish-tomentose to floccose or glabrate, infrequently green or gray and subglabrous or glabrous;

bracts 3, scalelike, linear to triangular, 1–5 mm.

capitate, 0.5–2 cm wide;

branches absent;

bracts absent immediately below involucre.

Peduncles

absent or mostly erect, slender, 0.3–1.5 cm, tomentose to floccose.

Involucres

1 per node, turbinate, (1.5–)2–3.5(–4) × 1.3–2.5(–3) mm, tomentose, floccose, subglabrous, or glabrous;

teeth 5, erect, (0.3–)0.5–1(–1.7) mm.

1 per node, campanulate, 2–3.5 × 2–4 mm;

teeth 6–9, lobelike, strongly reflexed, 2–3.5 mm.

Flowers

1.5–3(–4) mm;

perianth yellow or white to pink, orange, rose, red, or occasionally cream, glabrous;

tepals connate proximal 1/5–2/5, essentially monomorphic, oblong to obovate;

stamens usually exserted, 2.5–4 mm;

filaments sparsely to densely puberulent proximally.

2.5–10 mm, including 0.5–1 mm stipelike base;

perianth yellow to reddish or rose, densely pilose to villous abaxially;

stamens exserted, 3–4 mm;

filaments pilose proximally; staminate flowers shorter, 2.5–4 mm, tepals monomorphic, oblong-oblanceolate; pistillate flowers 2.5–10 mm, tepals slightly dimorphic.

Achenes

brown, 1.5–3 mm, glabrous.

light brown to brown, (3.5–)4–5 mm, glabrous or sparsely pubescent on beak.

Eriogonum microthecum

Eriogonum caespitosum

Phenology Flowering Apr–Jul.
Habitat Sandy to gravelly flats and slopes, mixed grassland, saltbush, sagebrush, and mountain mahogany communities, oak, pinyon and/or juniper and montane conifer woodlands
Elevation (1300-)1500-3000(-3700) m ((4300-)4900-9800(-12100) ft)
Distribution
from FNA
AZ; CA; CO; ID; MT; NM; NV; OR; UT; WA; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; ID; MT; NV; OR; UT; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 13 (13 in the flora).

Eriogonum microthecum is used as browse by deer and to a lesser degree by cattle and sheep. Some forms are now in cultivation. The species is reportedly used by the Piute of Nevada in the treatment of tuberculosis, lameness, rheumatism, and bladder trouble (P. Train et al. 1941). S. A. Weber and P. D. Seaman (1985) stated that A. F. Whiting found the plants being used as a tea by the Havasupai in northern Arizona. Members of E. microthecum are food plants for subspecies of the rare pallid blue butterfly (Euphilotes pallescens). Also found on this species is the cythera metalmark (Apodemia mormo cythera). Some authors have referred E. effusum to this species, even though the ranges of the two species do not overlap and intermediates are unknown.

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

Eriogonum caespitosum is widespread and usually common. It is variable throughout its range but no taxonomic subunits have been noted. The functionally staminate plants can be morphologically different from the functionally pistillate ones, and that may cause some confusion in the field, especially when the latter are in fruit. The plants are widely cultivated and worthy of consideration for the rock or sand garden. Plants from along the eastern edge of the Sierra Nevada in southern Mono County, California, form large, dense mats and would be most attractive in the garden. The scapelike flowering stem is technically a peduncle, being a further reduction of the inflorescence from that seen in E. douglasii. A specimen supposedly gathered in Nebraska (Abbott s.n., CAS) is discounted as to location.

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

Key
1. Perianths yellow
→ 2
1. Perianths various shades of white, cream, orange, pink, or red, not yellow
→ 4
2. Flowering stems and inflorescence branches usually glabrous; e Oregon and wc Idaho
var. microthecum
2. Flowering stems and inflorescence branches tomentose to floccose; se Oregon and sw Idaho s to e California and w Nevada
→ 3
3. Leaf blades (0.2-)0.3-0.6(-0.8) cm wide; flowers (1.5-)2-2.5(-3) mm; involucres 2-2.5 mm; achenes 1.5-2 mm; se Oregon and sw Idaho s to e California and w Nevada
var. ambiguum
3. Leaf blades 0.5-1.2 cm wide; flowers 2.5-3 mm; involucres 2.5-4 mm; achenes 2.5-3 mm; ne California, nw Nevada
var. schoolcraftii
4. Tomentum whitish (see also var. alpinum of the Sierra Nevada, California); flowering stems and inflorescence branches infrequently glabrous
→ 5
4. Tomentum brownish or reddish (may be white in var. alpinum), or flowering stems and inflorescence branches essentially glabrous
→ 6
5. Leaf margins not revolute; flowering inflorescence branches floccose or glabrous; northern phase of species
var. laxiflorum
5. Leaf margins revolute or nearly so; flowering inflorescence branches lanate to tomentose, or if subglabrous or glabrous, then southern phase of species
var. simpsonii
6. Plants shrubs, 3-6 dm
→ 7
6. Plants subshrubs, 0.2-1.5(-2) dm
→ 8
7. Flowering stems and inflorescence branches tomentose when young, becoming floccose at maturity; flowers 1.5-2(-2.5) mm; achenes 1.8-2 mm; Death Valley region, California
var. panamintense
7. Flowering stems and inflorescence branches lanate to tomentose at maturity; flowers 2-2.5(-3) mm; achenes 2.5-3 mm; Transverse Ranges, California
E. microthecumvar. corymbosoides
8. Leaf blades elliptic or ovate, margins not revolute; flowers (1.5-)2-3.5(-4) mm
→ 9
8. Leaf blades linear or linear-oblanceolate to narrowly elliptic, margins often revolute; flowers 1.5-2.5 mm
→ 10
9. Leaf blades 0.5-1 × (0.2-)0.3-0.5(-0.6) cm; involucres (2-)2.5-3 mm; flowers (2.5-)3-3.5(-4) mm; San Gabriel Mountains, California
var. johnstonii
9. Leaf blades 0.3-0.7(-0.8) × 0.1-0.4 cm; involucres 2.5-3.5 mm; flowers (1.5-)2-3.5 mm; desert ranges of se California, c Nevada, and Utah1f. Eriogonum microthecum var. lapidicola [8. Shifted to left margin—Ed.]
→ 8
10. Involucres 3-4 mm; perianths cream; San Bernardino Mountains, California
var. lacus-ursi
10. Involucres (1.5-)2-3 mm; perianths white, pink, red, or rose; Sierra Nevada of California, or e Nevada and w Utah
→ 11
11. Flowering stems glabrous; leaf blades sparsely floccose or glabrous adaxially; desert ranges, se Nevada
var. arceuthinum
11. Flowering stems white- to brownish-floccose to subglabrous, or reddish-tomentose to floccose; leaf blades floccose to subglabrous adaxially; California or wc Utah
→ 12
12. Tomentum white to brownish; Sierra Nevada, California
var. alpinum
12. Tomentum reddish; desert ranges, wc Utah
var. phoeniceum
Source FNA vol. 5, p. 242. FNA vol. 5, p. 364.
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. 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. 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. 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. microthecum var. alpinum, E. microthecum var. ambiguum, E. microthecum var. arceuthinum, E. microthecum var. johnstonii, E. microthecum var. lacus-ursi, E. microthecum var. laxiflorum, E. microthecum var. microthecum, E. microthecum var. panamintense, E. microthecum var. phoeniceum, E. microthecum var. schoolcraftii, E. microthecum var. simpsonii, E. microthecumvar. corymbosoides
Synonyms E. sphaerocephalum var. sericoleucum
Name authority Nuttall: Proc. Acad. Nat. Sci. Philadelphia 4: 15. (1848) Nuttall: J. Acad. Nat. Sci. Philadelphia 7: 50, plate 8, fig. 2. (1834)
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