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Blue Mountain buckwheat, strict buckwheat

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

Habit Herbs, erect, loosely to densely matted, not scapose, 1–5 × 1–10 dm, tomentose or glabrous. Herbs, erect, 1–4.5 dm, tomentose to floccose, grayish.
Stems

spreading to erect, with or without persistent leaf bases, up to 1/4 height of plant;

caudex stems absent or spreading to matted;

aerial flowering stems erect to spreading, slender, solid, not fistulose, 1–3 dm, tomentose or glabrous.

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

Leaves

basal, 1 per node;

petiole rarely twisted or curled, 1–6 cm, mostly tomentose;

blade elliptic to ovate, 0.5–2.5(–4) × (0.3–)0.5–1.5 cm, lanate, tomentose to floccose on both surfaces, sometimes sparsely tomentose to floccose and greenish or floccose to subglabrous or glabrous adaxially, margins 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

umbellate-cymose to cymose, 1–20 × 3–25 cm;

branches dichotomous, tomentose to floccose or less often glabrous;

bracts 3, scalelike, triangular, 1–3 mm.

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

branches tomentose to floccose;

bracts 0.5–2 × 0.5–1 mm.

Peduncles

absent.

absent.

Involucres

1 per node, rarely 2–5 per cluster, narrowly turbinate to turbinate-campanulate, 4–6 × 1.5–5 mm, tomentose or glabrous;

teeth 5, erect, 0.5–1.3 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

3–5(–6) mm;

perianth yellow or white to rose or purple, glabrous;

tepals connate proximally, dimorphic, those of outer whorl elliptic to nearly orbiculate, 2–3 × 2–3 mm, those of inner whorl oblanceolate to oblong, 3–4 × 1–2 mm;

stamens included to slightly exserted, 2–5 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.

light brown, 3-gonous, 1.7–2 mm;

beak smooth.

Eriogonum strictum

Eriogonum truncatum

Phenology Flowering Apr–Aug.
Habitat Sandy slopes, mixed grassland and chaparral communities, oak woodlands
Elevation 200-400 m (700-1300 ft)
Distribution
from FNA
CA; ID; MT; NV; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[BONAP county map]
Discussion

Varieties 4 (4 in the flora).

Eriogonum strictum, E. niveum, and E. ovalifolium form a complex of closely related species differing in leaf, inflorescence branching, and flower features. Variety proliferum appears to be the basal entity of the complex, approaching both E. niveum and E. ovalifolium var. pansum in its pubescence and branching pattern. Also, specimens of var. proliferum are sometimes difficult to differentiate from E. nudum var. oblongifolium. Careful observation, though, will permit well-made collections to be easily distributed among the individual species. An alternative taxonomy is to reduce all of the taxa to E. ovalifolium and recognize a series of subspecies and varieties. It is possible that additional study will show that E. strictum is sufficiently distinct from its tomentose to floccose counterparts to justify recognition of E. proliferum. In that case, both var. anserinum and var. greenei would be assigned to the latter species. Or, one could follow C. L. Hitchcock et al. (1955–1969, vol. 2) and recognize subsp. strictum as distinct from subsp. proliferum, with the latter consisting of varieties proliferum, anserinum, and greenei.

Members of the Eriogonum strictum are food plants for the Bauer’s dotted-blue butterfly (Euphilotes baueri).

(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.)

Key
1. Inflorescence branches glabrous
var. strictum
1. Inflorescence branches tomentose to floccose
→ 2
2. Perianths yellow
var. anserinum
2. Perianths white to rose or purple
→ 3
3. Leaf blades grayish-tomentose to floccose on both surfaces, or greenish-tomentose to floccose adaxially
var. proliferum
3. Leaf blades densely whitish-lanate to tomentose on both surfaces
var. greenei
Source FNA vol. 5, p. 317. FNA vol. 5, p. 418.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla 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. 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. 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
Subordinate taxa
E. strictum var. anserinum, E. strictum var. greenei, E. strictum var. proliferum, E. strictum var. strictum
Name authority Bentham: Trans. Linn. Soc. London 17: 414. (1836) Torrey & A. Gray: Proc. Amer. Acad. Arts 8: 173. (1870)
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