Gochnatia (Asteraceae, Mutisieae) and the Gochnatia-Complex: Taxonomic implications from morphology

FREIRE, S.E., KATINAS, L. & SANCHO, G.

ANNALS OF THE MISSOURI BOTANICAL GARDEN

MISSOURI BOTANICAL GARDEN

Lugar: Saint Louis, Estados Unidos de América; Año: 2002 vol. 89 p. 524 - 550

0026-6493

Gochnatia is one of the largest genera of the tribe Mutisieae(Asteraceae) and has been traditionally characterized by its homogamous capitula with isomorphic corollas. A morphological study of Gochnatia and associated genera, i.e., Actinoseris, Chucoa, Cnicothamnus, Cyclolepis, Hyalis, Ianthopappus, Nouelia, Pleiotaxis, and Wunderlichia, was carried out to evaluate the circumscription of Gochnatia and its sections, and the affinities of this complex of genera. The characters studied involve habit, leaf features (consistency, pubescence type, shape, margin, and venation), types of capitulescence, involucre features (shape, size, phyllary series, pubescence, and shape), paleae, floret features morphology,sex, number, color of corolla, anthers, style shapes, achenial pubescence, and pappus). Analysis of these features revealed: (1)although Gochnatia is highly variable in most of the characters studied, it can be defined by this suite of features: isomorphic to subdimorphic corollas, apiculate anther appendages, and smooth style branches; (2)sections of Gochnatia needed to be re-evaluated. As result of this, two sections, i.e., sect. Discoseris and sect. Pentaphorus,are confirmed; two sections are proposed, i.e., sect. Glomerata sect. nov. and sect. Rotundifolia sect. nov.; three sections are redefined, i.e., sect. Hedraiophyllum, sect. Leucomeris, and sect. Gochnatia, while sect. Anastraphioides is formally published; and (3) the combination of apiculate anther appendages and smooth style branches is unique to Actinoseris, Cnicothamnus, Cyclolepis, Gochnatia, Hyalis, Ianthopappus, and Nouelia within the Mutisieae. This group of genera is recognized here as the Gochnatia complex, with Gochnatia as the basal genus of this complex. Chucoa,Pleiotaxis, and Wunderlichia do not belong to the Gochnatia complex.