Flora of North America species comparison

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Eriogonum effusum

Eriogonum nudum

spreading buckwheat, spreading wild buckwheat

bare-stem buckwheat, barestem wild buckwheat, naked buckwheat, naked wild buckwheat, nude buckwheat
Habit Shrubs, spreading, not scapose, (1.5–)2–5(–7) × 5–15 dm, grayish- to reddish-brown-tomentose to floccose and gray or, rarely, thinly floccose and greenish. Herbs, mostly erect, infrequently scapose, (0.5–)1–15(–20) × 0.5–3 dm, glabrous or floccose to tomentose, usually greenish, occasionally grayish.
Stems

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

caudex stems absent;

aerial flowering stems erect to spreading, slender, solid, not fistulose, 0.3–0.8 dm, floccose or glabrous.

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

caudex stems absent;

aerial flowering stems erect to spreading, slender to stout, solid or hollow, occasionally fistulose, 0.3–4(–10) dm, glabrous or lanate to tomentose or floccose.
Leaves

cauline, 1 per node;

petiole 0.2–0.7 cm, tomentose to floccose;

blade oblanceolate to oblong or obovate, (1–)1.5–3 × (0.2–)0.3–0.7 cm, densely white-tomentose abaxially, white-floccose to glabrate or green and glabrous adaxially, margins plane.

basal or sheathing up stem 0.5–4 dm;

petiole 1–10 cm, glabrous or tomentose;

blade oblanceolate to elliptic or ovate, 1–6 × (0.3–)1–4 cm, densely white-lanate or tomentose abaxially, tomentose to floccose or subglabrous to glabrous adaxially, margins plane or undulate-crisped.
Inflorescences

cymose, 10–30(–40) × 10–40 cm;

branches dichotomous, white-floccose to glabrate or subglabrous;

bracts 3, scalelike, triangular, 0.5–2(–5) mm.

cymose, rarely umbellate or capitate, 2–100(–150) × 2–40(–80) cm;

branches usually dichotomous, glabrous or tomentose to floccose or sparsely pubescent;

bracts 3, scalelike, 0.5–3(–5) mm.
Peduncles

absent or mostly erect, slender, 0.3–2.5 cm, floccose.

absent.
Involucres

1 per node, turbinate, 1.5–2.5(–3) × 1–2 mm, tomentose to floccose;

teeth 5, erect, 0.3–0.6 mm.

1 per node or 2–10 per cluster, turbinate to turbinate-campanulate, (2.5–)3–5(–7) × (1.5–)2–4 mm, glabrous, tomentose, or sparsely pubescent;

teeth 5–8, 0.2–0.6 mm.
Flowers

2–4 mm;

perianth yellow, glabrous;

tepals connate proximal 1/4, essentially monomorphic, elliptic to obovate;

stamens mostly exserted, 2–4.5 mm;

filaments sparsely pilose proximally.

(1.5–)2–4 mm;

perianth white or yellow, sometimes pink or rose, glabrous or pubescent;

tepals connate proximal 1/4, monomorphic, oblong to obovate;

stamens exserted, 2–5 mm;

filaments pilose proximally.
Achenes

brown, 2–2.5 mm, glabrous.

light brown to brown, 1.5–3.5 mm, glabrous.

Eriogonum effusum

Eriogonum nudum
Phenology Flowering Jun–Sep.
Habitat Sandy to rocky slopes and flats, mixed grassland and sagebrush communities, juniper and montane conifer woodlands
Elevation 1200-2500 m (3900-8200 ft)
Distribution
from FNA
CO; MT; NE; NM; SD; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; NV; OR; WA; nw Mexico
[WildflowerSearch map]
[BONAP county map]
Discussion

Eriogonum effusum is rather common on the northern Great Plains and along the eastern slope of the Rocky Mountains in central and eastern Colorado, southeastern Montana, western Nebraska, northern New Mexico, southwestern South Dakota, and southeastern Wyoming. Some specimens from Chaffee County, Colorado, are thinly floccose and greenish (Atwood & Welsh 29689, BRY) and thus similar to E. leptocladon. A collection from Pyramid Lake, Washoe County, Nevada (Frandsen & Brown 182, NESH) is clearly mislabeled. A roadside collection of E. effusum gathered near Little America, Sweetwater County, Wyoming, in 1961 (G. Mason 4025, ASU) was an introduction that has not persisted.

The spreading wild buckwheat is occasionally merged with Eriogonum microthecum even though the two are morphologically distinct and their ranges do not overlap. Plants in New Mexico are sometimes difficult to distinguish from the related E. leptocladon var. ramosissimum. The species is the food plant for the Rita dotted-blue butterfly (Euphilotes rita). A hybrid between Eriogonum effusum and E. pauciflorum has been named E. ×nebraskense Rydberg [E. multiceps Nees subsp. nebraskense (Rydberg) S. Stokes; E. pauciflorum Pursh var. nebraskense (Rydberg) Reveal]. The hybrid is known from Weld County, Colorado; Cheyenne and Kimball counties, Nebraska; and Converse and Platte counties, Wyoming.

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

Varieties 13 (13 in the flora).

Several local groups of Native Americans in California used members of this species in a variety of ways. S. A. Barrett and E. W. Gifford (1933) and S. M. Schenck and E. W. Gifford (1952) reported the consumption of raw young stems that are rather moist and tasty, although there is a sour aftertaste. The Kawaiisu used the hollow stems (probably var. westonii, rather than var. pauciflorum) as drinking tubes and as pipes (M. L. Zigmond 1981). Zigmond reported also that the roots of var. pauciflorum are used as an infusion for coughs.

Members of Eriogonum nudum are food plants for the Bauer’s dotted-blue butterfly (Euphilotes baueri), the Pacific dotted-blue (E. enoptes), the gorgon copper (Gaeides gorgon), and the Mormon metalmark (Apodemia mormo).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Involucres and inflorescence branches tomentose to floccose; leaves usually basal
→ 2
1. Involucres and inflorescence branches glabrous or, if pubescent, leaves sheathing up stems
→ 3
2. Perianths white; flowering stems lanate to tomentose; leaf blades 2-3.5 cm; s Sierra Nevada
var. regirivum
2. Perianths yellow or white to rose; flowering stems tomentose to floccose; leaf blades 2-4 cm; s Oregon, n California, wc Nevada
var. oblongifolium
3. Leaves sheathing up stems, margins often strongly undulate-crisped
→ 4
3. Leaves basal, margins plane or slightly undulate-crisped
→ 8
4. Flowering stems tomentose
→ 5
4. Flowering stems glabrous
→ 6
5. Perianths pubescent; flowers 1.5-2 mm; involucres 3-4 mm; Sierra Nevada, California
var. regirivum
5. Perianths glabrous; flowers 3-4 mm; involucres 4-6 mm; Coast Ranges, California
var. decurrens
6. Leaf blades densely lanate abaxially, tomentose adaxially; involucres 5-10 per cluster; Sierra Nevada, California
var. murinum
6. Leaf blades tomentose abaxially, less so to floccose, glabrous, or nearly so adaxially; involucres 1 per node or 2-5 per cluster; widespread, Coast Ranges, California
→ 7
7. Flowering stems occasionally fistulose; involucres (2-)3-5 per cluster; perianths white to pink, rarely yellowish
var. auriculatum
7. Flowering stems strongly fistulose; involucres 1 per node; perianths pale yellowish white to yellow or white
var. indictum
8. Involucres 1(-2) per cluster
var. westonii
8. Involucres 2-10 per cluster
→ 12
9. Flowering stems fistulose; perianths yellow, infrequently white; c California
var. westonii
9. Flowering stems not fistulose or, if so, plants of sw California; perianths white, rarely yellow
→ 10
10. Perianths pubescent or, infrequently, glabrous; s California
var. pauciflorum
10. Flowers glabrous; sw Oregon, n California, Nevada
→ 11
11. Leaf blades 1-5 cm; sw Oregon, n California (including w slope of Sierra Nevada), Washington
var. nudum
11. Leaf blades 1-2 cm; Sierra Nevada of California and adjacent desert ranges of wc Nevada
var. deductum
12. Perianths pubescent, often yellow
→ 13
12. Perianths usually glabrous abaxially, white, rarely yellow
→ 14
13. Flowering stems not fistulose; leaf blades floccose or glabrous adaxially, margins plane; plants of nonaridregions
var. pubiflorum
13. Flowering stems slightly to distinctly fistulose; leaf blades tomentose to floccose adaxially, margins undulate-crisped; plants of arid regions
var. westonii
14. Inflorescences capitate or nearly so; alpine, Sierra Nevada
E. nudumvar. scapigerum
14. Inflorescences cymose or, if capitate, not alpine.
→ 15
15. Involucres 1(-2) per cluster, 5- 7 mm; mountains of s California
var. pauciflorum
15. Involucres 2-10 per cluster, 3-5 mm; mountains and foothills of c and n California or coastal bluffs. [16. Shifted to left margin—Ed.]
→ 16
16. Inflorescences cymose and branched 2 or more times; involucres 2-5 per cluster; mountains and foothills of c and n California, Oregon, and Washington.
var. nudum
16. Inflorescences capitate or cymose and branched 1-2 times; involucres 5-10 per cluster; coastal bluffs, sw Oregon, ne California
var. paralinum
Source FNA vol. 5, p. 248. FNA vol. 5, p. 309.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla
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. 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
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. 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. nudum var. auriculatum, E. nudum var. decurrens, E. nudum var. deductum, E. nudum var. indictum, E. nudum var. murinum, E. nudum var. nudum, E. nudum var. oblongifolium, E. nudum var. paralinum, E. nudum var. pauciflorum, E. nudum var. pubiflorum, E. nudum var. regirivum, E. nudum var. westonii, E. nudumvar. scapigerum
Synonyms E. microthecum var. effusum E. latifolium subsp. nudum
Name authority Nuttall: Proc. Acad. Nat. Sci. Philadelphia 4: 15. (1848) Douglas ex Bentham: Trans. Linn. Soc. London 17: 413. (1836)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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