(Vol.10, 2007-12) The Asteraceae of Northwestern Pico Zunil, a Cloud Forest in Western Guatemala

From 2003 to 2005, 46 genera and 96 species of native Asteraceae were collected on the northwestern slopes of Pico Zunil, a montane cloud forest habitat in southwestern Guatemala. Combining the present survey with past collections, a total of 56 genera and 126 species of Asteraceae have been reported from Pico Zunil, five of which are naturalized Old World species. In the present study, the Heliantheae contains the greatest number of native species (29). The most diverse genus is Ageratina (Eupatorieae, 9 species). Species richness of native Asteraceae measured along an elevational gradient ranged from a low of 16 species at 3400–3542 m to a high of 68 species at 2300–2699 m, where human land use most actively affects cloud forest habitat. Of the plants collected, Ageratina rivalis and Verbesina sousae were new species records for Guatemala. Six more species were new records for the Department of Quetzaltenango: Ageratina pichinchensis, A. prunellaefolia, A. saxorum, Koanophyllon coulteri, Stevia triflora, and Telanthophora cobanensis. In addition, 16 of the 96 native species collected are known only from to the western montane departments of Guatemala and the montane regions of southern Chiapas, Mexico. We provide a base of information against which future studies can measure temporal changes in presence of species such as may accompany environmental changes resulting from human activities and/or climate change.