Gamochaeta pensylvanica
Gamochaeta argyrinea
gamochaeta pensylvanica, Pennsylvania cudweed, Pennsylvania everlasting, Pennsylvania everlasting-cudweed
silver cudweed, silvery cudweed, silvery everlasting
erect to decumbent or procumbent, loosely arachnose-tomentose.
decumbent-ascending, closely white-pannose (hairs usually individually evident, seldom forming clothlike induments).
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.
basal and cauline, basal present through flowering, blades oblanceolate to oblanceolate-oblong or oblanceolate-obovate, 1.5–5(–8) cm × 5–12(–18) mm (gradually smaller distally), faces bicolor, abaxial closely white-pannose, adaxial sparsely arachnose (evident at 10x).
cupulate-campanulate, 3–3.5 mm, bases sparsely arachnose.
campanulate, 3–3.5 mm, bases sparsely arachnose.
bisexual 3–4; all (or at least bisexual) corollas usually purplish distally.
bisexual 4–5(–6); all corollas purple- to yellow-brown distally.
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.
in 4–6 series, outer (tawny-transparent, never dark brown) ovate to ovate-lanceolate, lengths 1/3–4/5 inner, apices acute to acuminate, inner elliptic-oblong to oblong, laminae often purplish tinged (around stereome/lamina junction, otherwise hyaline and slightly brownish), apices truncate-rounded, apiculate (flexing slightly outward in fruit).
in glomerules in continuous or interrupted, spiciform arrays 1–12 cm × 10–15 mm (pressed).
initially in continuous, cylindric arrays 1.5–5 cm × 10–12 mm (pressed), later sometimes interrupted, 5–18 cm × 10–12 mm (pressed; producing axillary glomerules from proximal nodes).
(tan) 0.4–0.5 mm.
(tan) 0.5–0.6 mm.
= 28.
Gamochaeta pensylvanica
Gamochaeta argyrinea
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.)
Gamochaeta argyrinea has been confused with G. purpurea, which also occurs across the coastal states of eastern United States (G. L. Nesom 2004).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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