Asteraceae tribe Vernonieae
J. Phys. Chim. Hist. Nat. Arts88: 203. 1819
Mostly tropics and warm-temperate regions of New World and Old World.
Genera 100–140, species ca. 1300 (6 genera, 25 species in the flora).
Most members of Vernonieae are herbs, subshrubs, or shrubs (Vernonia arborea Buchanan-Hamilton of tropical Asia may form trees to 33 m). They are characterized by discoid heads of bisexual florets with purple to pink or white corollas, calcarate anthers, attenuate, abaxially hirsutulous style branches stigmatic ± uniformly (rather than in two lines or bands) nearly to their tips, and pollen grains with regular, polygonal, patterns of ± spiny to smooth ridges. Centers of species concentration for the tribe are found in Africa, Madagascar, South America, and Antilles. In the flora, most species are found in the eastern and southern states of the United States. The plants are often associated with open, prairie or savanna-like areas.
Treating clades recognized by J. L. Panero and V. A. Funk (2002) as corresponding to tribes, Vernonieae is sister to Liabeae (none in the flora) and is included with Arctotideae (introduced), Cichorieae, and Gundelieae (none in the flora) within Cichorioideae.
Historically, 80% or so of the species in the tribe were included in Vernonia. H. Robinson (1999) has argued for resurrections and recircumscriptions of some old genera and recognition of some “new” genera, resulting in a Vernonia of ca. 20 species.
Stokesia laevis and some Vernonia species are grown as ornamentals. Some Vernonia species have been used medicinally in folk remedies and some may be locally troublesome as weeds (e.g., V. baldwinii).
|1||Heads pseudo-radiant (corollas of peripheral, bisexual florets enlarged, zygomorphic); margins of phyllaries (at least the outer), pectinately spinose-toothed||Stokesia|
|1||Heads ± discoid; margins of phyllaries not pectinately spinose-toothed||> 2|
|2||Heads sessile, borne in congested clusters; florets (1–)4(–5) in each head||> 3|
|2||Heads mostly pedunculate, not borne in congested clusters; florets 9–100+ in each head||> 4|
|3||Heads (1–)10–40 per cluster, each cluster subtended by (2–)3 ± deltate bracts; pappi of 5(–6) 1-aristate scales (look closely for squamiform, gradually to abruptly tapering base of each arista), no scales tipped with plicate aristae||Elephantopus|
|3||Heads 1–5+ per cluster, each cluster subtended by 1–2 lanceolate to spatulate or linear bracts; pappi of 6–10 ± laciniate to aristate scales, 2(–3+) of aristate scales each with awnlike arista plicate (2-folded) distally||Pseudelephantopus|
|4||Annuals (perhaps persisting); cypselae not ribbed||Cyanthillium|
|4||Perennials or functionally annuals; cypselae 8–10-ribbed||> 5|
|5||Heads each subtended by 3–8+, ± foliaceous bracts; pappi caducous||Centratherum|
|5||Heads not each subtended by foliaceous bracts; pappi persistent||Vernonia|