Based on H. Robinson F&G Flowering Pl. H. (2007) 8: 157-158

Plants perennial herbs with decumbent bases; hairs simple or symmetrically T-shaped. Leaves usually alternate, rarely subopposite, sometimes all basal, often glandular. Synflorescences cymose, branches longer than the central axes. Heads homogamous, usually pedunculate; phyllaries about 50, free, in 5-6 series; flowers 8-20, bisexual, narrowly cylindrical near the base, widening abruptly, 5-lobed; anthers without tails, with linear or lanceolate, often glandular, distal appendages; style branches  long-tapering, with stigmatic papillae near the base on the upper (adaxial) surfaces, pilose on the lower surfaces, hairs acute, sometimes septate. Achenes 5-6-ribbed, with minute hairs, glands, and/or idioblasts; raphides subquadrate; pappuses usually 2-seriate, the outer whorl of short scales, the inner whorl capillary. 

As described above, Vernonia has about 22 species, all native from the southeastern U.S. and Bahamas south to Central Mexico. In the Flora of Somalia, Beentje adopted the more traditional interpretation of the genus which included about 500 species because work on the genus should be interpreted was not settled.  The key will be modified to reflect the current placement of the species Beentje included in Vernonia, as will there treatment in OpenHerbarium.  

H. Beentje (2206) 3: 489 - 494

Plants annual or perenial herbs, often with annual stems from woody rootstocks, or shrubs to trees. Leaves usually alternate, rarely subopposite, sometimes developing from the rootstock, often glandular. Heads homogramous, with 1-many flwoers, clustered in corymbiform cymes or various paniculate, spicate, or pther clusters; phyllaries free, in several series, imbricate, the tips sometimes with a colored appendage. Flowers usually bisexual and fertile, with narrowly cylindrical bases, widening abruptly, 5-lobed, the lobes equal; anthers with linear or lancelate appendages at the tips; style branches long-tapering, their lower surfaces pilose. their upper surfaces stigmatic papillose above near their base. Achenes of various shapes, smooth or ribbed, with or without a distinct basal callus; pappuses usually of 2 series, an outer whorl of short scales or bristles, the inner of long bristles, the outer whorl sometimes falling early. 

Vernonia includes about 500 species anbd is native to both the Old and New Worlds. The genus is undergoing revision which is likely to result in the Old World species being transferred to different genera. 

©Trustees of the Royal Botanic Gardens, Kew; reproduced with permission.

Key to the species of Somaliland and Somalia.

Global distribution of Vernonia.