Description:

• Perennial, rarely annual, herbs
• Leaves alternate, sessile, entire, toothed or rarely incised, often nerves conspicuously raised, hairy or glabrous and sometimes glandular
• Capitula radiate, large or medium-sized, occasionally small, solitary or in panicles or corymbs, pedunculate
• Involucre campanulate or subhemispherical; bracts imbricate, in 3 or 4(5) rows
• Receptacle flat or convex, epaleate
• Ray florets female, fertile or rarely sterile; staminodes sometimes present; corolla blue, violet or white, in 1 or 2 rows, tubular below, mostly glandular-hairy, often hairy as well, produced into a strap-shaped, 3-toothed lamina in upper part
• Disc florets bisexual, fertile or rarely inner ones functionally male; corolla yellow, rarely purplish, tubular, expanded above, 5-toothed, always glandular-hairy
• Anthers ecalcarate and ecaudate; apical appendage ovate-lanceolate, flat
• Style branches narrowly oblong; apex triangular, with conspicuous sweeping hairs outside
• Cypselas elliptic to obovate, compressed, bright to dark brown to blackish, usually with thickened margins, hairy and with multicellular glands
• Pappus in 2 rows, inner row of bristles, outer of short narrow scales or bristles or in 1 row, of bristles only
• x = 8, 9 (5, 7) (aneuploids, high polyploidy, B-chromosomes)

Classification Notes:

• J.C. Semple (University of Waterloo, Canada) (pers. comm.) believes there are no true Aster species in southern Africa

Nomenclature:

• Aster L.
  • Linnaeus: 872 (1753)
  • Linnaeus: 373 (1754)
  • Lippert: 153 (1973)
  • Hilliard: 59 (1977)
  • Bremer: 413 (1994)

Distribution & Notes:

• Global: Species ± 250, mainly northern hemisphere, America, Europe and Asia
• Southern Africa: Species 16, 1 naturalised, widespread