Gamochaeta purpurea |
Gamochaeta pensylvanica |
|
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purple everlasting-cudweed, spoon-leaf cudweed, spoon-leaf purple everlasting |
gamochaeta pensylvanica, Pennsylvania cudweed, Pennsylvania everlasting, Pennsylvania everlasting-cudweed |
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Habit | Annuals (sometimes winter annuals), 10–40(–50) cm; fibrous-rooted or taprooted. | Annuals, 10–50 cm; taprooted. |
Stems | erect to decumbent-ascending, densely but loosely pannose or pannose-tomentose. |
erect to decumbent or procumbent, loosely arachnose-tomentose. |
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, proximal usually present at flowering, blades spatulate to oblanceolate-obovate, 2–7 cm × 4–16 mm (becoming spatulate to oblanceolate bracts among proximal heads, surpassing glomerules, bases narrowed to petiolar regions, margins sinuate, apices often apiculate), faces concolor or weakly bicolor, loosely tomentose. |
Involucres | turbinate-cylindric, 4–4.5 mm, bases sparsely arachnose. |
cupulate-campanulate, 3–3.5 mm, bases sparsely arachnose. |
Florets | bisexual 3–4; all corollas usually purplish distally. |
bisexual 3–4; all (or at least bisexual) corollas usually purplish distally. |
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 3–4 series, outer ovate-triangular, lengths 1/2–2/3 inner, apices attenuate-apiculate, inner oblong, laminae often purple-tinged (at stereome), apices (transparent, sometimes golden) acute to obtuse. |
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). |
in glomerules in continuous or interrupted, spiciform arrays 1–12 cm × 10–15 mm (pressed). |
Cypselae | (tan) 0.6–0.7 mm. |
(tan) 0.4–0.5 mm. |
2n | = 14, 28. |
= 28. |
Gamochaeta purpurea |
Gamochaeta pensylvanica |
|
Phenology | Flowering Apr–May(–Jun). | Flowering Mar–Jun(–Aug). |
Habitat | Open, usually disturbed, commonly sandy habitats, roadsides, fields, woodland clearings and edges | Disturbed sites, exposed, moist soils, commonly partially shaded |
Elevation | 5–300 m (0–1000 ft) | 0–500 m (0–1600 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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AL; CA; FL; GA; LA; MA; MD; MS; NC; OK; PA; SC; TX; VA; Mexico; Central America; South America; Europe; Asia; Africa; Australia
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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.) |
Gamochaeta pensylvanica is recognized by its obovate-spatulate, loosely tomentose and concolor or weakly bicolor basal and proximal cauline leaves, and similarly shaped spreading bracts among the heads. Occasional plants appear intermediate between G. pensylvanica and G. antillana. The latter differs in its more erect stems, linear to oblanceolate basal and proximal cauline leaves, and more nearly continuous arrays of heads with linear to narrowly oblanceolate bracts. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 19, p. 433. | FNA vol. 19, p. 437. |
Parent taxa | Asteraceae > tribe Gnaphalieae > Gamochaeta | Asteraceae > tribe Gnaphalieae > Gamochaeta |
Sibling taxa | ||
Synonyms | Gnaphalium purpureum, G. rosacea, Gnaphalium rosaceum | Gnaphalium pensylvanicum, Gnaphalium peregrinum |
Name authority | (Linnaeus) Cabrera: Bol. Soc. Argent. Bot. 9: 377. (1961) | (Willdenow) Cabrera: Bol. Soc. Argent. Bot. 9: 375. (1961) |
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