Gamochaeta purpurea |
Gamochaeta |
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purple everlasting-cudweed, spoon-leaf cudweed, spoon-leaf purple everlasting |
cudweed, everlasting |
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Habit | Annuals (sometimes winter annuals), 10–40(–50) cm; fibrous-rooted or taprooted. | Annuals, biennials, or perennials, (1–)5–65 cm; taprooted or fibrous-rooted [subrhizomatous]. | ||||||||||||||||||||||||||||||||||||||||||||
Stems | erect to decumbent-ascending, densely but loosely pannose or pannose-tomentose. |
1+, usually erect, sometimes decumbent-ascending. |
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Leaves | basal and cauline, basal and proximal cauline usually withering before flowering; blades oblanceolate to spatulate, 1–6 cm × 5–14 mm (distal similar, at least among proximal heads, margins sometimes sinuate), faces usually bicolor, abaxial closely white-pannose, adaxial usually sparsely arachnose (basal cells of hairs persistent, expanded, glassy), sometimes glabrescent. |
basal and cauline; alternate; sessile; blades mostly linear to oblanceolate or spatulate, bases cuneate to ± cordate, margins entire, sometimes sinuate, abaxial faces mostly white or gray and tomentose or pannose-tomentose, adaxial green and glabrescent or glabrous, or grayish and arachnose, loosely tomentose, or subpannose. |
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Involucres | turbinate-cylindric, 4–4.5 mm, bases sparsely arachnose. |
narrowly to broadly campanulate, 2.5–5 mm. |
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Receptacles | flat (concave in fruit), glabrous, epaleate. |
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Florets | bisexual 3–4; all corollas usually purplish distally. |
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Pistillate florets | 50–130, more numerous than bisexual florets; corollas all yellow or purplish-tipped. |
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Bisexual florets | 2–7; corollas all yellow or distally purplish. |
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Phyllaries | in 4–5 series, outer ovate-triangular, lengths 1/3–2/3 inner, apices acute-acuminate, inner triangular-lanceolate (usually striate), laminae purplish (in bud) to whitish or silvery (in fruit), apices acute (not apiculate). |
in 3–7 series, unequal, mostly brownish to stramineous, sometimes purplish, hyaline, often shiny, distally chartaceous to scarious, eglandular. |
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Heads | initially in continuous spiciform arrays 1–4(–5) cm × (5–)10–15 mm, later interrupted (glomerules widely separated, bracteate, the proximal often on relatively long peduncles). |
disciform, usually in glomerules borne in continuous or interrupted, usually spiciform, sometimes paniculiform, arrays (reduced to terminal glomerules in depauperate individuals). |
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Cypselae | (tan) 0.6–0.7 mm. |
oblong, slightly flattened, faces with papilliform hairs (myxogenic, their lengths about equaling diams.); pappi readily falling, of 12–28 barbellulate bristles in 1 series (basally connate in smooth rings, falling as units). |
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x | = 7. |
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2n | = 14, 28. |
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Gamochaeta purpurea |
Gamochaeta |
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Phenology | Flowering Apr–May(–Jun). | |||||||||||||||||||||||||||||||||||||||||||||
Habitat | Open, usually disturbed, commonly sandy habitats, roadsides, fields, woodland clearings and edges | |||||||||||||||||||||||||||||||||||||||||||||
Elevation | 5–300 m (0–1000 ft) | |||||||||||||||||||||||||||||||||||||||||||||
Distribution |
AL; AR; AZ; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MO; MS; NC; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; WV; HI; ON; Mexico; South America; West Indies; Central America (Nicaragua)
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North America; Mexico; Central America; South America; West Indies; some species adventive and naturalized in Europe; Asia; Australia; and elsewhere |
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Discussion | Gamochaeta purpurea apparently is native to North America and adventive elsewhere. Basal cells of hairs on adaxial faces of leaves are expanded and glassy (versus hairs filiform to bases in most other species) and are diagnostic for Gamochaeta purpurea. From Maryland northward, plants of G. purpurea produce relatively small basal rosettes and relatively shallow fibrous roots or a filiform taproot; southward and southwestward, the basal rosettes often are larger and the fibrous roots are denser. Gamochaeta purpurea apparently occurs widely through the world as a weed; it is fairly clearly native to eastern North America, where it is the least weedy of the gamochaetas. Plants of G. purpurea in southern Arizona along perennial streams at the base of the Santa Catalina Mountains were first collected in 1903 (G. L. Nesom 2004) and were, perhaps, accidentally established through visitation; the same sites are heavily infested by other, more aggressive, nonnative species. Collections of G. purpurea also have been made at higher elevations in the Santa Catalina, Rincon, and Chiricahua mountains, where the species is less likely to have been introduced by human activity. It also seems unlikely that plants in scattered Mexican localities were introduced there by human activity. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species ca. 50 (12 in the flora). Gamochaeta comprises about 50 species (A. L. Cabrera 1961; S. E. Freire and L. Iharlegui 1997) or about 80 species (Cabrera 1977+, part 10), all native to the Americas. Most are known only from South America; some apparently are native to Mexico and the flora area (G. L. Nesom 2004b). Some species are strongly weedy and have extended non-native ranges. Because of inconsistencies in the identification of those species, it has been difficult to evaluate the overall distributions of the widespread species. The distinctiveness of Gamochaeta was emphasized by A. L. Cabrera (1961, and in later floristic treatments of South American species) and by other botanists who have treated it as a separate genus in the last decade. The genus is distinguished by its combination of relatively small heads in spiciform arrays, concave post-fruiting receptacles, truncate collecting appendages of style branches in bisexual florets, relatively small cypselae with minute, mucilage-producing papilliform hairs on the faces, and pappus bristles basally connate in smooth rings and released as single units. It seems likely that most species are primarily autogamous, in view of the tiny, non-showy heads that barely open through flowering. The consistency of vegetative and floral features in some of the species supports this hypothesis. In the flora area, some species have commonly been treated as variants within Gamochaeta purpurea; distinctions are evident in the field, where it is common to find as many as five species growing in proximity without intergradation. Species of Gamochaeta are distinguished by differences primarily in root form, leaf shape, nature and distribution of indument, and phyllary morphology. Chromosome counts have been reported for some species; because of the unreliability of identifications, vouchers for those counts should be restudied. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 19, p. 433. | FNA vol. 19, p. 431. | ||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Asteraceae > tribe Gnaphalieae > Gamochaeta | Asteraceae > tribe Gnaphalieae | ||||||||||||||||||||||||||||||||||||||||||||
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Synonyms | Gnaphalium purpureum, G. rosacea, Gnaphalium rosaceum | Gnaphalium section G., Gnaphalium subg. G. | ||||||||||||||||||||||||||||||||||||||||||||
Name authority | (Linnaeus) Cabrera: Bol. Soc. Argent. Bot. 9: 377. (1961) | Weddell: Chlor. Andina 1: 151. (1856) | ||||||||||||||||||||||||||||||||||||||||||||
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