Introduction

Communities of Espeletia, known locally as ‘frailejones’, constitute the dominant and most striking physiognomic elements of the high montane páramo vegetation of the northern Andes (Figure 13.1). Different species occupy a variety of habitats, ranging from cloud forest, as low as 1500 m in elevation, to close to the upper limit of plant growth, at 4700 m. With over 130 currently recognized species and a wide diversity of life forms and other morphological features, Espeletia has been noted as one of the foremost examples of adaptive radiation in plants (Carlquist 1974).

One of the keys to understanding the ways that groups such as Espeletia have successfully colonized different habitats in high, tropical mountains lies in a study of their reproductive systems. Vegetative reproduction in Espeletia is rare and occurs to a limited extent in just a few species that produce axillary rosettes close to the ground (Cuatrecasas 1979). Seed dispersal is also very restricted, due to the absence of a pappus or other specialized dispersal structure (Cuatrecasas 1976; Smith 1981; Guariguata 1985). Thus, the breeding and pollination systems are the major determinants of gene flow in Espeletia and constitute an important factor affecting the genetic structure of populations.

The little previous information on the reproductive biology of Espeletia was obtained from studies undertaken in the páramos of Edo. Mérida, Venezuela.