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(Last Modified On 6/13/2013)
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(Last Modified On 6/13/2013)
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Genus
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Gnaphalium L.
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PlaceOfPublication
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Sp. PI. 850. 1753
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Synonym
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Euchiton Cass. in Levr., Dict. Sci. Nat. 56: 215. 1828. TYPE: E. pulchellus Cass. Omalotheca Cass. in Levr., Dict. Sci. Nat. 56: 218. 1828. TYPE: 0. supinum (L.) Cass. Gamochaeta Wedd., Chlor. And. 1: 151. 1855. TYPE: G. americana (Miller) Wedd. Gnaphalion St.-Lag., Ann. Soc. Bot. Lyon 7: 127. 1880, nom. nud. TYPE: G. dysodes St.-Lag. (nomen).
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Description
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Lanate or tomentose herbs, rarely suffruticose, often branched; stems leafy, rarely creeping. Leaves alternate, simple, entire or crenulate margined, lanate or tomentose at least in part, the hairs arachnoid, but sometimes glandular; petioles mostly wanting. Inflorescence an open or dense cymose panicle, racemose spike, or scapose with a congested, sometimes interrupted cluster of few or many heads, the clusters or heads mostly subtended by bracts or bracteoles. Heads small, disciform, with many florets, both staminate and pistillate florets present but often few of one sex, cyathiform or spindle shaped; involucral bracts many, imbricate in several series, sometimes apically corolloid, white, yellowish, sometimes with a rose or purplish cast; receptacle flat, naked, or sometimes with rudimentary, ephemeral chaff; ray florets with the capillary corolla basally expanded and contracted upwards, apically notched but without a distinct limb or ligule, the androecium wanting, the ovary fertile or rudimentary; disc florets tubiform, apically 5-lobed, about as long as the ray florets, the anthers connate, basally tailed, the tails some- times fimbriate, the appendage obtuse, the style branches truncate, apically fringed with trichomes, unappendaged, the nectary conspicuous. Achenes little or not compressed, sometimes 4-many ribbed, glabrous or with glandular-appearing tubercles; pappus of fine smooth or strigulose bristles in one series, sometimes basally united and falling as a unit, in other cases free or nearly so and falling separately.
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Habit
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herbs
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Distribution
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A genus of 100-300 species of cosmopolitan distribution, the species of Gnaphalium are most numerous in Africa, Mexico, and upland South America.
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Note
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A comprehensive revision of the genus has never been undertaken for any extensive region of the world, and a number of species have been named many times. The limits of the genus are not clear, and distinctions between Gnaphaliumn and Anaphalis, Helichrysum, and other groups may not be valid. Drury (1970) assessed a number of characters with a view toward delimiting these groups. Other discussions of these groups have been given by Cabrera (1961, 1963), Drury (1971, 1972), and Godfrey ( 1958). Known in Panama as weeds of upland pastures and roadsides, many species in various parts of the world are credited with medicinal properties. Some are cultivated as ornamentals in temperate gardens. Although there are no reports of toxicity to livestock from living plants, some species may cause nitrate poisoning in stock when fermented with silage.
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Common
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Cudweed Vira-vira
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Reference
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Cabrera, A. L. 1961. Observaciones sobre las Inuleae-Gnaphalineae (Compositae) de America del sur. Bol. Soc. Argent. Bot. 9: 359-386. Cabrera, A.L. 1963. Compuestas. In Flora de la Provincia de Buenos Aires. VI. Coleccion Cientifica del I.N.T.A., Buenos Aires. Drury, D. G. 1970. A fresh approach to the classification of the genus Gnaphalium with particular reference to the species present in New Zealand (Inuleae-Compositae). New Zealand Jour. Bot. 8: 222-248. Drury, D. G. 1971. The American spicate cudweeds adventive to New Zealand. New Zealand Jour. Bot. 9: 157-135. Drury, D. G. 1972. The cluster and solitary-headed cudweeds native to New Zealand. New Zealand Jour. Bot. 10: 112-179. Godfrey, R. K. 1958. A synopsis of Gnaphalium (Compositae) in the south- eastern United States. Quart. Jour. Florida Acad. Sci. 21: 177-184.
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Key
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a. Inflorescence spicate; involucral bracts with brown tips; pappus united at the base and falling as a unit ...... 1. G. americanum aa. Inflorescence of glomerules of heads, sometimes congested or in open panicles; involucral bracts without contrasting brown tips; pappus separating at the base and falling as separate bristles. b. Leaves all lanceolate, not becoming linear near the inflorescence, glabrate and glandular above; receptacle 2-4 mm across; involucral bracts often chalky (under a lens) ...... 3. G. domingense bb. Upper leaves mostly linear, especially near the inflorescence, eglandular, glabrate or pubescent above; receptacle less than 1.6 mm across; involucral bracts shiny, not chalky. c. Heads often pinkish; inflorescence congested; leaves glabrescent above, those near the inflorescence often forming a pseudo-involucre; plants to 30 cm tall, branching at the base ...... 4. G. roseum cc. Heads not pinkish; inflorescence often an open panicle; leaves mostly sparingly lanate above, not clustered near the inflorescence; plants to 70 cm tall, often branching above the base ...... 2. G. attenuatum
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