Vol. 36: Panero, Jose L.: Systematics of Pappobolus (Asteraceae-Heliantheae). 1992. 64 figs. 195 p. gr8vo. Paper bd.

Pappobolus as circumscribed here includes the taxa previously placedin Pappobolus (sensu Blake 1916), the South American species ofHelianthus (recently known as Helianthopsis), and one speciestransferred from Viguiera, V. acutifolia. It consists of 47 taxa (38species), 20 of which are newly described. The genus is distinguished from closely related genera such as Simsia, Tithonia, and Viguiera bythe caducous pappus of the disk achenes and a shrubby to arborescenthabit. Pappobolus is endemic to the Andes of Colombia, Ecuador, andPeru. It occupies habits ranging from xerophytic and tropical deciduousforests to montane moist forest: some species also occur in the jalcaof northern Peru. The greatest concentration of species is in northernPeru in the basin of the Maranon River. Leaf venation patterns andfloral microcharacters, such as endothecial cell morphology and styleshape, are essentially identical among the species of the genus.Chromosome numbers obtained from a majority of the species support abase chromosome number of x=17 for the genus and indicate a lack ofpolyploidy. Morphological data supports the recognition of two subgenera. Pappobolus subg. Apricola with nine species is distinguished by yellowanther thecae and disk flower lobes, large determinate, monochasial,thyrsoid capitulescences and small heads. Pappobolus subg. Pappoboluswith 29 species is distinguished by black anther thecae and disk flowerlobes, determinate monochasial and dichasial, thyrsoid capitulescences(some associated with few, large heads), densely lanate herbage, andsclerified leaves. Keys and distribution maps are provided for all thespecies. Most species are illustrated.