INTRODUCTION TO GEONOMA

Andrew Henderson

New York Botanical Garden, Bronx, NY 10458

ahenderson@nybg.org

Geonoma is one of the largest three palm genera in the Neotropics, approximately equal in size to Bactris and Chamaedorea. Species of Geonoma are common in lowland and montane tropical moist forests in Central and South America, and just reach the Caribbean, occurring from sea level to just over 3000 m elevation. Geonoma are usually rather small, understory palms, although some reach the canopy of montane forests.

The genus was described 200 years ago by Willdenow (1805). The first revision of the whole genus was that of Burret (1930), published as Geonomeae americanae, where 172 species were recognized. The second and most recent revision of Geonoma was that of Wessels Boer (1968), where 75 species were recognized. Since 1968, 11 new species have been described.

Geonoma is difficult taxonomically. Henderson et al. (1995) stressed that this taxonomic complexity was a result of the occurrence of several widespread and variable species. These species may contain several distinct forms at one locality, but these are linked by intermediates at other localities.

In January 2003 I began a taxonomic revision of Geonoma. Because it is likely to take several years to complete the revision, I am making preliminary results available on this web site. I have begun by studying several of the variable and widespread species of Geonoma. In order to understand these, I am using morphometric methods based on study of morphological variables taken from herbarium specimens. The philosophy behind this approach is outlined in Henderson (2005).

This taxonomic revision, and this web site, is organized by species groups, 17 of which were recognized by Wessels Boer (1968). I follow this here, with some modifications as discussed under each group. These groups are used merely as a convenience. I do not intend to imply that they consist of related species, nor have I studied them in any particular order. The composition of the groups may change as the study proceeds. So far, I have revised the following species groups (named for the first species described in the group): G. triandra (group 1), G. stricta (group 8), G. deversa (group 9), G. interrupta (group 11), G. baculifera (group 12), G. undata (groups 5, 14, 15), G. maxima (groups 16, 17), and G. aspidiifolia. The site will be updated as more groups are revised.