Centipeda pleiocephala
N.G.Walsh Tall SneezeweedErect slender annual, to 30(–40) cm high; branches glabrous except for a few cottony hairs on young growth and occasionally in axils. Leaves more or less oblong to narrowly obovate, 8–25 mm long, 2–7 mm wide, serrate, surfaces glabrous, resin-dotted. Capitula hemispherical to biconvex at anthesis, 2–4.5 mm diam., 2–4 racemosely arranged (rarely solitary), axillary, lowest capitulum sessile or subsessile, the upper 1–3 with peduncles to c. 5 mm long; involucral bracts spathulate to obovate with ruminate membranous margins, 1–1.5 mm long; receptacle convex; female florets c. 100–170, corollas 0.2–0.3 mm long; bisexual florets (4–)10–18, corollas 0.6–0.8 mm long. Fruiting heads disintegrating when mature on still-growing plants. Cypselas obloid, narrowly obovoid, or narrowly obcuneoid, 0.8–1.1(1.3) mm long; ribs 2–4, barely raised, with antrorsely appressed hairs; intervening faces lacking vesicular trichomes or very sparse; apex obtuse or rounded (female florets) or truncate (bisexual florets), forming a pale, spongy portion up to a quarter the cypsela length. Flowers mostly Sept.–Nov.
MuM, Wim, VRiv, MSB, RobP, MuF, Gold. Also WA, NT, SA, Qld, NSW. In Victoria grows in moist sandy, silty or clay soils in floodplains and the edges of watercourses near the Murray River from Mildura west and between Kerang and Ulupna Island .
This species is morphologically similar to Centipeda minima but can be distinguished by its erect habit and axillary, shortly racemose inflorescences typically of 2–4 capitula. Despite its morphological similarity to C. minima, analyses of DNA data has revealed that it is probably most closely related to C. nidiformis (Nylinder et al. 2013).
SpinningNylinder, S.; Cronholm, B.; de Lande, P.J.; Walsh, N.G.; Anderberg, A.A. (2013). Species tree phylogeny and character evolution in the genus Centipeda (Asteraceae): evidence from DNA sequences from coding and non-coding loci from the plastid and nuclear genomes. Molecular Phylogenetics and Evolution 68(2): 239–250.
