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shortstem buckwheat, shortstem wild buckwheat

buckwheat family

Habit Herbs, matted, cespitose, pulvinate, erect or spreading, sometimes scapose, (0.3–)1–5 × 1–5(–8) dm, tomentose to floccose or glabrous, grayish or greenish to green. Trees, shrubs, vines, or herbs, perennial, biennial, or annual, homophyllous (heterophyllous in some species of Polygonum), polycarpic (rarely monocarpic in Eriogonum); roots fibrous or a solid or, rarely, chambered taproot, rarely tuberous.
Stems

matted to spreading, occasionally with persistent leaf bases, up to 1/4 or more height of plant;

caudex stems matted or spreading;

aerial flowering stems spreading to erect or nearly so, slender, rarely stout, solid, not fistulose, (0.4–)0.5–2(–2.5) dm, glabrous, floccose, or sparsely to densely tomentose to lanate.

prostrate to erect, sometimes scandent or scapose, solid or hollow, rarely with recurved spines (some species of Persicaria), glabrous or pubescent, sometimes glandular;

nodes swollen or not;

tendrils absent (except in Antigonon and Brunnichia);

branches free (adnate to stems distal to nodes and appearing to arise internodally in Polygonella);

caudex stems (subfam.

Leaves

basal or more commonly sheathing 1–7(–15) cm up stem, 1 per node;

petiole 0.2–2(–4) cm, tomentose to floccose;

blade linear, oblanceolate, or spatulate to elliptic, (0.2–)1–10(–12) × 0.1–0.9(–1.2) cm, densely tomentose abaxially, less so to floccoseadaxially, margins plane or revolute, sometimes crenulate.

deciduous (persistent in Coccoloba and sometimes more than 1 year in Antigonon, Eriogonum, Chorizanthe, and Polygonella), basal or basal and cauline, rosulate, mostly alternate, infrequently opposite or whorled;

stipule (ocrea) absent (subfam.

Inflorescences

cymose, subumbellate, umbellate, or capitate, (1–)3–10(–25) × (0.7–)1–10(–15) cm;

branches dichotomous, sometimes absent, tomentose to floccose or glabrous;

bracts 3, triangular, scalelike, 1–3(–5) mm.

terminal or terminal and axillary, cymose and dichotomously or trichotomously branched, or racemose, umbellate, or capitate (subfam.

Peduncles

absent or erect, 0.3–3 cm, tomentose to floccose or glabrous.

Involucres

1 per node or 3–7(–9) per cluster, turbinate to turbinate-campanulate, 1.5–4(–5) × (1–)1.5–3(–3.5) mm, tomentose to floccose or glabrous;

teeth 5, erect to spreading, 0.3–1 mm.

Pedicels

present or absent, rarely accrescent (Brunnichia), articulate to flowers.

Flowers

(1–)2–4 mm;

perianth various shades of white to cream or yellow, glabrous or pubescent;

tepals connate proximal 1/4–1/3, monomorphic, lanceolate, oblong to obovate or ovate to oval;

stamens exserted, 2–4 mm;

filaments pilose basally.

usually bisexual, sometimes bisexual and unisexual on same or different plants, rarely unisexual only, 1–many, often with stipelike base distal to articulation;

perianth persistent, often accrescent in fruit, often greenish, white, pink, yellow, red, or purple, rarely winged or keeled (Fallopia and some species of Polygonum), campanulate to urceolate, sometimes membranous, indurate (Brunnichia and Emex), or fleshy (Coccoloba, Muehlenbeckia, and some species of Persicaria) in fruit, rarely developing raised tubercles proximally (Rumex), glabrous or pubescent, sometimes glandular or glandular-punctate;

tepals 2–6, distinct or connate proximally and forming tube, usually in 2 whorls, petaloid or sepaloid, dimorphic or monomorphic, rarely coriaceous (Lastarriaea), entire, emarginate, or lobed to laciniate apically, rarely awn-tipped (Lastarriaea);

nectary a disk at base of ovary or glands associated with bases of filaments;

stamens (1–)6–9, staminode rarely present;

filaments distinct, or connate basally and sometimes forming staminal tube, free or adnate to perianth tube, glabrous or pubescent proximally;

anthers dehiscing by longitudinal slits;

pistil 1, (rudimentary pistil sometimes present in staminate flowers of monoecious or dioecious taxa), (2–)3(–4)-carpellate, homostylous (heterostylous in some species of Fagopyrum and Persicaria);

ovary 1-locular (sometimes with vestigial partitions proximally);

ovule 1, orthotropous or, rarely, anatropous, placentation basal or free-central;

styles 1–3, erect to spreading or recurved, distinct or connate proximally;

stigmas 1 per style, peltate, capitate, fimbriate, or penicillate.

Fruits

achenes, included or exserted, yellowish, brown, red, or black, homocarpic (sometimes heterocarpic in Polygonum), winged or unwinged, 2-gonous, 3-gonous, discoid, biconvex, lenticular, rarely 4-gonous or spheroidal, glabrous or pubescent.

Achenes

light brown to brown, 2–3 mm, glabrous except for roughened to papillate beak.

Seeds

1;

endosperm usually abundant, mealy, development nuclear;

embryo straight or curved, rarely folded.

Eriogonoideae

) tightly compact to spreading and at or just below the soil surface or spreading to erect and above the soil surface, woody;

aerial flowering stems prostrate or decumbent to erect, arising at nodes of caudex branches, at distal nodes of aerial branches, or directly from the root, slender to stout and solid or slightly to distinctly fistulose, rarely disarticulating in ringlike segments (Eriogonum).;

eriogonoideae , possibly vestigial in some perennial species of Chorizanthe) or present (subfam.; eriogonoideae );

or spikelike, racemelike, paniclelike, cymelike, or, rarely, capitate (subfam.; eriogonoideae , rarely absent in Eriogonum), glabrous or pubescent;

peduncle present or absent;

clusters of flowers subtended by involucral bracts or enclosed in typically nonmembranous tubular involucres (subfam.; eriogonoideae ) or subtended by connate bracteoles forming a persistent membranous tube (ocreola) (subfam.

Polygonoideae

), persistent or deciduous, cylindric to funnelform, sometimes 2-lobed (Polygonum), chartaceous, membranous, coriaceous or partially to entirely foliaceous;

petiole present or absent, rarely articulate basally (Fagopyrum, Polygonella, Polygonum), rarely with extrafloral nectaries (Fallopia, Muehlenbeckia);

blade simple, margins entire, occasionally crenulate, crisped, undulate, or lobed, rarely awn-tipped (Goodmania).;

polygonoideae ), comprising simple or branched clusters of compound inflorescences;

bracts absent (subfam.; polygonoideae ), or 2–10+, usually connate proximally or to 1/2 their length, rarely perfoliate, foliaceous or scalelike, margins entire, sometimes awn-tipped (subfam.; polygonoideae ).

Eriogonum brevicaule

Polygonaceae

Distribution
from FNA
CO; ID; MT; NE; NV; SD; UT; WY
[WildflowerSearch map]
[BONAP county map]
Widespread; well represented in the north-temperate zone
[BONAP county map]
Discussion

Varieties 8 (8 in the flora).

Eriogonum brevicaule is highly variable, and the variation has yet to be fully resolved taxonomically. The expressions recognized here will encompass the vast majority of populations. The extreme variation previously under the name var. laxifolium is now reduced with the recognition of var. bannockense (low-elevation or northern phase), var. nanum, and var. caelitum (high-elevation, southern phases).

Essentially all of the following species (28–63 below) belong to the Eriogonum brevicaule complex. Eriogonum desertorum, E. loganum, E. spathulatum, E. ostlundii, and E. artificis are allied to the complex associated with var. laxifolium, while E. natum is related to var. cottamii. Eriogonum viridulum and E. ephedroides are allied to E. brevicaule var. brevicaule as are E. contortum and E. acaule. Eriogonum brandegeei is also related, but exactly how is less certain. Allied to this complex of species are on the one hand those related to E. batemanii, and on the other all of the matted perennials belonging to the E. ochrocephalum complex. Essentially all of these species form relatively small populations on discrete edaphic sites and are well isolated one from the other. Unfortunately, a clear separation of E. brevicaule from E. desertorum, E. loganum, and E. spathulatum is not always possible.

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

Genera 48, species ca. 1200 (35 genera, 442 species in the flora).

Monophyly of Polygonaceae is well supported by molecular studies (M. W. Chase et al. 1993; P. Cuénoud et al. 2002; A. S. Lamb Frye and K. A. Kron 2003), which place it sister to Plumbaginaceae. Wood anatomy also supports this relationship (S. Carlquist 2003). Polygonaceae has been divided variously into subfamilies (S. A. Graham and C. E. Wood Jr. 1965; K. Haraldson 1978; J. Brandbyge 1993); two often are recognized based on morphological evidence: Eriogonoideae and Polygonoideae. Recent studies using the chloroplast gene rbcL suggest Eriogonoideae are monophyletic and Polygonoideae are paraphyletic (Lamb Frye and Kron). Generic limits have been much debated, particularly the circumscription of Polygonum in the broad sense. Morphological, cytological, palynological, and anatomical data, although useful in resolving some questions about the circumscriptions and relationships of genera, have not provided a consensus regarding relationships within the family. Pollen types (J. W. Nowicke and J. J. Skvarla 1977) and chromosome numbers (Brandbyge) are diverse. Multiple base chromosome numbers have been documented in some genera, and polyploidy is common. The classification used here generally follows J. L. Reveal (1978) for Eriogonoideae and Haraldson for Polygonoideae.

A characteristic feature of the family is the ocrea, a nodal sheath variously interpreted as an outgrowth of the sheathing base of the petiole, as connate stipules, or as an expanded axillary stipule (S. A. Graham and C. E. Wood Jr. 1965). It is absent in subfamily Eriogonoideae except in some perennial, South American members of Chorizanthe, where it is rudimentary (J. L. Reveal 1978).

The flowers of Polygonaceae have been studied extensively. Most researchers concluded that six tepals is the primitive condition in the family (R. A. Laubengayer 1937), but A. S. Lamb Frye and K. A. Kron (2003) concluded that five tepals is the primitive condition, and that taxa with six or four tepals evolved multiple times within the family. The same molecular study also suggested parallel evolution of growth forms and woodiness. Floral nectaries are useful generic characters in the Polygonoideae (L.-P. Ronse Decraene and J. R. Akeroyd 1988) but their utility in floristic treatments is limited because of their small size. In some genera of Polygonaceae, the outer tepals are connate and form a slender, stipelike hypanthium base above the articulation with the true pedicel. In the Polygonoideae treatments, pedicel refers to the true pedicel plus the stipelike hypanthium above the articulation; in Eriogonoideae, stipe refers only to the stipelike hypanthium base, and pedicel is applied only to the true pedicel.

Members of the family are of relatively minor economic importance (A. N. Steward 1930; S. A. Graham and C. E. Wood Jr. 1965). Fagopyrum has been cultivated for millennia, Coccoloba produce edible fruits, and the petioles of Rheum and leaves of some species of Rumex are edible. Many species have been used as food or medicine or for ceremonies by various tribes of Native Americans. Outside the flora area, the family includes some tropical trees harvested for timber (Coccoloba and Triplaris). Some species of Fallopia, Persicaria, Polygonum, and Rumex are cosmopolitan weeds, and Emex is a pernicious weed in parts of the world. Of the 35 genera in the flora, four are entirely non-native: Emex, Fagopyrum, Muehlenbeckia, and Rheum. Antigonon and Coccoloba are popular ornamentals in the southern part of the flora region. Many species of Eriogonum are planted in rock gardens. Persicaria species are important wetland plants because waterfowl consume their fruits.

Mechanisms for achene dispersal vary greatly. Hooked or awned involucres occur in many genera of subfam. Eriogonoideae. The outer tepals of the perianth expand into wings (Fallopia) or spines (Emex), or the achene has wings (Eriogonum alatum, Oxyria, Rheum, and Rumex), which aid in dispersal by wind or water. The achenes are forcibly tossed from the plant in Persicaria virginiana, and persistent, hooked styles aid in their transport by animals. In Coccoloba, the fleshy tube of the tepals aids in dispersal by birds.

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

Key
1. Flowering stems and inflorescence branches glabrous
→ 2
1. Flowering stems and inflorescence branches floccose to tomentose or lanate
→ 3
2. Plants not pulvinate or cespitose, (0.8-)1.5-5 dm; inflorescences cymose, open, divided 3 times or more; widespread
var. brevicaule
2. Plants pulvinate and cespitose, 0.3-1.5(-1.8) dm; inflorescences capitate or umbellate to cymose and divided 1-2 times; Utah
var. nanum
3. Perianths pubescent; se Montana, ne Wyoming
var. canum
3. Perianths glabrous; sc Idaho, ne Nevada, Utah, sw Wyoming, not se Montana or ne Wyoming
→ 4
4. Inflorescences divided (2-)3-5 times; perianths usually yellow, rarely ochroleucous
→ 5
4. Inflorescences capitate or umbellate to cymose and divided 1-2 times; perianths ochroleucous or yellow
→ 6
5. Flowers (1-)1.5-2.5 mm; sw Wyoming
var. micranthum
5. Flowers (2.5-)3-4 mm; Utah
var. cottamii
6. Leaf blades linear to narrowly oblanceolate; inflorescences capitate or divided
→ 7
6. Leaf blades linear, oblanceolate, or narrowly oblanceolate to elliptic; inflorescences capitate. [8. Shifted to left margin.—Ed.]
→ 8
7. Leaf blades (1.5-)3-9(-12) × 0.1-0.5(-0.7) cm, tomentose abaxially, less so and grayish or occasionally greenish adaxially, margins usually revolute, occasionally plane; perianths ochroleucous or yellow; n Utah, se Idaho, below 2800 m
var. laxifolium
7. Leaf blades 0.2-4.5(-5) × (0.2-)0.3-0.6(-0.7) cm, tomentose abaxially, thinly floccose and bright green adaxially, margins plane or slightly thickened; perianths yellow; c Utah, above 2700 m
var. caelitum
8. Leaf blades and flowering stems bright green under the thinly floccose pubescence; ne Nevada and nw Utah
var. laxifolium
8. Leaf blades and flowering stems usually grayish to dull greenish under tomentum, rarely thinly floccose; se Idaho and sw Wyoming s to n Utah and ne Nevada
→ 9
9. Leaf margins crenulate; leaf blades narrowly oblanceolate to narrowly elliptic, (0.3-)0.5-1.5(-2) × 0.2-0.5(-7) cm, densely white-tomentose abaxially, floccose and greenish adaxially
var. nanum
9. Leaf margins usually plane (rarely crenulate in Wyoming); leaf blades narrowly oblanceolate to oblanceolate, (0.8-)1-4(-4.5) × (0.3-)0.4-0.8 cm, densely tomentose abaxially, tomentose to floccose and grayish to greenish adaxially
var. bannockense
1. Ocreae absent; nodes not swollen; flowers usually enclosed in involucres or subtended byinvolucral bracts, these rarely absent (in Gilmania)
Polygonaceae subfam. Eriogonoideae
1. Ocreae present, persistent or deciduous; nodes usually swollen; flowers not enclosed in involucres or associated with involucral bracts
Polygonaceae subfam. Polygonoideae
Source FNA vol. 5, p. 264. FNA vol. 5, p. 216. Authors: Craig C. Freeman, James L. Reveal.
Parent taxa 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. 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. 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. brevicaule var. bannockense, E. brevicaule var. brevicaule, E. brevicaule var. caelitum, E. brevicaule var. canum, E. brevicaule var. cottamii, E. brevicaule var. laxifolium, E. brevicaule var. micranthum, E. brevicaule var. nanum
Synonyms E. campanulatum subsp. brevicaule
Name authority Nuttall: Proc. Acad. Nat. Sci. Philadelphia 4: 15. (1848) Jussieu
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