Linzia Sch. Bip. ex Walp., 1843 Figures 13 B; 15 A–B; 16 A–E

Linzia Sch. Bip. ex Walp., Rep. 2: 948. 1843. - Type: Linzia vernonioides Sch. Bip. ex Walp.

Vernonia sect. Azurae S.B. Jones, Rhodora 83: 74. 1981. - Type: Linzia glabra Steetz in Peters.

Descriptions.

Perennial herbs; stems with simple multiseptate hairs. Leaves alternate, subsessile to short-petiolate. Inflorescence corymbiform cymes or single heads with short to long peduncles. Involucre funnelform to campanulate; bracts 50-150 in 5-6 series, often pectinate-denticulate with spicules along lateral margins, outer tips often elongate, green and recurved; receptacle epaleaceous. Florets ca. 20-50 in a head; cortollas bluish, tube very long, funnelform near throat; throat very short, lobes apically stiffly pilosulous; anther base rounded; apical appendage glabrous, triangular with thickened ornamentation in center; style base with small annuliform node. Achenes strongly 10-costate, usually with rows of idioblasts or specialized cells along sides of costae, surface setuliferous, setulae slender with pairs of cells not or scarcely separated at tip, raphids subquadrate to short-oblong; pappus of many somewhat persistent long bristles, with outer series short. Chromosome number n = 10 (Jones 1979, 1982).

Pollen tricolporate, psilolophate, with spur muri intruding into short colpi above and below pore, single polar lacunae often present, not echinate, with or without micropunctations resticted to muri. Muri showing baculae with broadened base, branching distally into many bacula-like branches (Fig. 16 E), a form that seems almost transitional to a rhizomate condition.

Most notable secondary metabolites, sesquiterpene germacranolides, elemanolides (Bohlman and Jakupoic 1990, as Vernonia glabra Vatke & Vernonia melleri Oliv. & Hiern).