Vernoniastrum
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Ordo: Asterales
Familia: Asteraceae
Name
Vernoniastrum H. Rob., 1999 – Wikispecies link – Pensoft Profile
- Vernoniastrum H. Rob.. Proc. Biol. Soc. Wash. 112(1): 233. 1999. – Type: Crystallopollen latifolium Steetz in Peters.
- Vernonia sect. Lepidella Oliv. & Heirn, Fl. Trop. Afr. 3: 267. 1877, non Lepidella Tiegh. 1912 or Lepidella E.J. Gilbert 1925. – Type: Vernonia petersii Oliv. & Hiern.
- Vernonia subsect. Lepidella (Oliv. & Hiern) S.B. Jones, Rhodora 83: 72. 1981.
Descriptions
. Annual or perennial herbs 0.3–1.0 m tall; stems pilose, hairs simple with elongate apical cells with slightly asymmetric bases. Leaves alternate. Inflorescence with 1–many heads. Involucre campanulate; involucral bracts ca. 50 in ca. three series, gradate, persistent; receptacle epaleaceous. Florets ca. 50 in a head; corollas reddish-purple, basal tube narrowly funnelform, throat shorter than lobes or anther thecae, lobes pilosulous distally; anther bases acuminate to acutely tailed; apical appendage glabrous, with thin cell walls. Style base with node; style branches with acicular sweeping hairs. Achenes 4–6-angled, setulae aparse on sides, idioblasts usually grouped in transverse bands, raphids elongate; pappus bristles subpersistent, marginally densely barbellate; outer squamae persistent. Chromosome number n = 10 (Jones 1979[1], 1982[2]).
Pollen triporate, lophate, perforated tectum discontinuous in lacunae, muri papillate, with or without micropunctations on muri (Fig. 25 D–I). With habit similar to Polydora but often perennial, lacking L-shaped hairs, having tailed anther bases, and a chromosome number n = 10. Also characteristic of the core element of Vernoniastrum are the transverse bands of crowded idioblasts in the achene walls.
Taxon Treatment
- Robinson, H; Skvarla, J; Funk, V; 2016: Vernonieae (Asteraceae) of southern Africa: A generic disposition of the species and a study of their pollen PhytoKeys, (60): 49-126. doi
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Other References
- ↑ Jones S (1979) Chromosomes of the Vernonieae (Compositae). Bulletin of the Torrey Botanical Club 106: 79–84. doi: 10.2307/2484281
- ↑ Jones S (1982) Pp. 126–127 In: Löve A (Ed.) IOPB Chromosome number reports LXXIV. Taxon 31: 119–128. http://www.jstor.org/stable/1219710?seq=1#page_scan_tab_contents