Common Names in English:
The largest family of flowering plants , the Compositae (Asteraceae), comprising about 1,100 genera and more than 20,000 species and characterized by many small flowers arranged in a head looking like a single flower and subtended by an involucre of bracts. A head may consist of both ray flowers and disk flowers, as in the sunflower, of disk flowers only, as in the burdock, or of ray flowers only, as in the dandelion.
The Lactuceae are a tribe of closely related genera of the sunflower family that are easily recognized because the flowering heads are composed of wholly of ligulate florets that are usually 5-lobed. Another very distinguishing feature is the milky sap . Although not apparent without magnification, the pollen is distinctive in that the spines are more or less restricted to discrete ridges or flanges on the surface of the grain. In other members of the family the spines are distributed more or less evenly over the surface of the pollen grain . The pappus usually consists of scales or stiff hairs . -- Gerald D. Carr.
, 10-200 cm, taprooted, or perennials
, 10-100 cm. with deeply seated, woody caudices or stout or slender, creeping
rhizomes. Stems (1-8) erect
or branched, usually glabrous
, sometimes hairy
(especially when young). Leaves basal (withered at flowering in annuals and some perennials) and/or cauline (much reduced, bractlike in annuals and some perennials) ; usually sessile; blades
, or spatulate
, usually runcinate, margins
usually pinnately lobed
(spinulose-tipped in S. parryi), sometimes entire or toothed
(S. lactucina, S. tenuifolia, and S. fluminea (faces
, or tomentose
) ; distal bractlike (to 45 mm in S. fluminea). Heads borne singly or clustered (in paniculiform
arrays in some subspecies
of S. exigua). Peduncles not inflated
distally, sometimes bracteate
. Calyculi of 3-5, unequal bractlets
in some perennials; not distinguishable in S. cichoriacea), appressed
(some annuals). Involucres ± cylindric
, 2-3(-5+) mm diam. Phyllaries usually 5-12 in 1 series, equal (20-25 in 2-3 series, unequal in S. cichoriacea, usually glabrous, rarely puberulent, densely stipitate-glandular
in S. exigua subsp.
deanei). Receptacles flat, usually smooth
in S. cichoriacea), glabrous, epaleate. Florets (4-) 5-16; corollas usually pink or lavender, sometimes white (annuals often purple-tinged abaxially). Cypselae light tan to dark brown, columnar
, sometimes slightly curved
, 5-angled, apices truncate
, faces equal, sometimes with ribs
between faces, each face with central, narrow, longitudinal
or furrow (not grooved
in S. virgata), otherwise smooth or bumpy to tuberculate
, usually glabrous (scaberulous in S. fluminea) ; pappi persistent
(or only widened bases
persistent after distal portions break
off) or falling, of 5-40, distinct
or basally connate
in groups, white to tan, wholly or distally plumose bristles in 1 series. x = 8.
Species 16: w North America, n Mexico.
Because all the species of Stephanomeria have not previously been examined at one time, the present treatment provides the first unified picture of their variability, ecologic specializations, and geographic distributions. The genus includes six annual species (all in the flora ) and ten perennial species (eight in the flora, one in the mountains of northern Baja California, and one known only from Guadalupe Island, Mexico).
Taxonomic distinctions among annual species of Stephanomeria did not become evident until their morphology and geographic distributions were correlated with their chromosome numbers and reproductive compatibilities (L. D. Gottlieb 1971, 1972). The same studies also provided an hypothesis that satisfactorily accounted for their variability. Studies showed that S. exigua and S. virgata differed for a relatively large number of characters and that other annual species originated from genetic segregates that were formed by hybridization, at both diploid and tetraploid levels, as well as directly from S. exigua.
Stephanomeria exigua has five subspecies; S. virgata has two. Within each species, the subspecies share numerous morphologic features as well as chromosomal karyotype . They are recognized as polytypic because reproductive compatibility between any pair of subspecies of S. exigua or between subspecies of S. virgata is substantially higher than is the compatibility between the two species. The two species appear to represent a fundamental phylogenetic divergence within annuals; nevertheless their different features are combined in different ways in S. elata and S. diegensis.
Stephanomeria paniculata and S. malheurensis probably evolved more or less directly from S. exigua subsp. coronaria. The speciation process that gave rise to S. malheurensis (L. D. Gottlieb 1978) has been examined in a series of studies (Gottlieb 1973b, 1977, 1979; S. Brauner and Gottlieb 1987, 1989). The origin of the highly self-pollinating S. paniculata may have been similar but much less evidence is available. Stephanomeria malheurensis has served as a model for reintroduction of a species back into its original habitat after local extinction , in its case by competition from invasive cheatgrass (Bromus tectorum).
Information about evolution and speciation is not so available for the perennials as for the annuals. Treatment of perennials is based almost entirely on examination of herbarium specimens plus published information describing their chromosome numbers. Although little is known about phylogenetic relationships among perennial species of Stephanomeria, a recent DNA sequencing study of nuclear rDNA (J. Lee et al. 2002) showed that the genus does not include either Munzothamnus blairii (previously S. blairii) or Pleiacanthus spinosus (previously S. spinosa). Without them, Stephanomeria is a well-supported, monophyletic group of species.
The DNA analysis suggested that Stephanomeria tenuifolia, S. runcinata, S. fluminea, and S. thurberi comprise a subclade. Those four species are perennial and all have fully plumose , white pappus bristles. They differ markedly in their ecologic specializations, as indicated in their treatments below. The DNA studies also showed a very close relationship between S. malheurensis and S. exigua subsp. coronaria consistent with results of previous studies (cited above). It is to be hoped that taxonomic information presented below will make species of Stephanomeria more easily accessible to continuing studies.
- Whittaker & Margulis,1978
- Haeckel, 1866
- Cavalier-Smith, 1981
- Sinnott, 1935 ex Cavalier-Smith, 1998
- Vascular Plants
- Brongniart, 1843
- Takhtajan, 1967
- Takhtajan Ex Reveal, 1992
- Lindley, 1833
- Giseke, 1792, nom. cons., nom. alt.
- Nuttall, 1841, nom. cons.
- Stickweed, wirelettuce. skeletonweed [Greek stephanos, crown. wreath, and meris, part, presumably alluding to appearance of plumose bristles of pappus]
- Specific epithet:
- Botanical name: - Stephanomeria diegensis Gottlieb
- Specific epithet: diegensis - Gottlieb
- Genus: Stephanomeria () - Nuttall, 1841, nom. cons. - Stickweed, wirelettuce. skeletonweed [Greek stephanos, crown. wreath, and meris, part, presumably alluding to appearance of plumose bristles of pappus]
- Subtribe: Stephanomeriinae ()
- Tribe: Lactuceae ()
- Subfamily: Cichorioideae ()
- Family: Compositae () - Giseke, 1792, nom. cons., nom. alt.
- Order: Asterales () - Lindley, 1833
- Superorder: Campanulanae () - Takhtajan Ex Reveal, 1992
- Subclass: Asteridae () - Takhtajan, 1967
- Class: Spermatopsida () - Brongniart, 1843
- Subphylum: Euphyllophytina ()
- Phylum: Tracheophyta () - Sinnott, 1935 ex Cavalier-Smith, 1998 - Vascular Plants
- Subkingdom: Viridaeplantae () - Cavalier-Smith, 1981
- Kingdom: Plantae () - Haeckel, 1866 - Plants
Status: Accepted Name
Comment: Data Providers: CONABIO, IPNI, Tropicos. GCC LSID: urn :lsid:compositae.org:names:274889A9-BB04-4921-8EA1-360B193B5945
Last scrutiny: 16-Aug-09
Members of the genus Stephanomeria
ZipcodeZoo has pages for 27 species, subspecies, varieties, forms, and cultivars in this genus:
S. blairii (Blair's Wirelettuce) · S. cichoriacea (Chicoryleaf Wirelettuce) · S. diegensis (Wreathplant) · S. elata (Santa Barbara Wirelettuce) · S. exigua (Small Wirelettuce) · S. exigua deanei (Deane's Wirelettuce) · S. exigua exigua (Small Wirelettuce) · S. exigua macrocarpa (Small Wirelettuce) · S. lactucina (Creeping Wirelettuce) · S. lygodesmoides (Skeleton Wirelettuce) · S. malheurensis (Malheur Wire Lettuce) · S. minor (Lesser Wirelettuce) · S. minor var. minor (Narrowleaf Wirelettuce) · S. minor var. myrioclada (Narrowleaf Wirelettuce) · S. minor var. uintensis (Uinta Wirelettuce) · S. paniculata (Tufted Wirelettuce) · S. parryi (Parry Wire Lettuce) · S. pauciflora (Brownplume Wirelettuce) · S. pauciflora var. Pauciflora (Wire-Lettuce) · S. runcinata (Desert Wirelettuce) · S. schottii (Schott Wire Lettuce) · S. spinosa (Spiny Skeletonweed) · S. tenuifolia var. tenuifolia (Narrowleaf Wirelettuce) · S. thurberi (Thurber Wire Lettuce) · S. virgata (Rod Wirelettuce) · S. virgata pleurocarpa (Wand Wirelettuce) · S. wrightii (Wright's Wirelettuce)
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- 1997 IUCN red list of threatened plants Cambridge: IUCN, World Conservation Union, 1998 url p. 196.
- Compositae newsletter. Columbus, Ohio: Dept. of Botany, Ohio State University, 1975- url p. 30.
- Gottlieb, L. D. 1971. Evolutionary relationships in the outcrossing diploid annual species of Stephanomeria (Compositae). Evolution 25: 312-329.
- Gottlieb, L. D. 1972. A proposal for classification of the annual species of Stephanomeria (Compositae). Madroño 21: 463-481.
- Brands, S.J. (comp.) 1989-present. The Taxonomicon. Universal Taxonomic Services, Zwaag, The Netherlands. Accessed January 12, 2012.
Accessed through GBIF Data Portal November 21, 2007:
- Berkeley Natural History Museums, University and Jepson Herbaria DiGIR provider
- USDA PLANTS, USDA PLANTS Database
- Biodiversity Heritage Library NamebankID: 2664927
- Catalogue of Life Accepted Name Code: Ast-10218
- Global Biodiversity Information Facility Taxonkey: 13767630
- Globally Unique Identifier: urn:lsid:ipni.org:names:251178-1
- Integrated Taxonomic Information System (ITIS) Taxonomic Serial Number (TSN): 196300
- U.S.D.A. Plant Symbol: STDI6
- Zipcode Zoo Species Identifier: 64513