Análisis cladístico de la familia Agavaceae

A morphological based cladistical analysis was undertaken, using 20 taxa from or associated to the family Agavaceae. To assess homologous and independent characters, the morphology of each taxa was analyzed under the next criteria: a. plants have modular construction; b. plant morphology evolves through ontogenetic changes; c. morphological characters evolve through sequential modifications. Hypotheses on character evolution were proposed and tested with comparative and cladistical methods. The morphological characters were optimized with the Wagner parsimony method using PAUP 3.1.1 , considering the genera Chlorogalum and Camassia (Hyacinthaceae), and Chlorophytum and Eremocrinum (Anthericaceae) as multiple outgroups. Two equal most parsimony trees were obtained, 163 steps long with a Consistency Index of 0.509. From the strict consensus tree, genera of Funkiaceae (Hesperocallis, Hosta) resulted as sister taxa of Agavaceae. Chlorophytum and Camassia, considered in molecular biology studies as closely related to Agavaceae, resulted further down. Within the Agavaceae sensu stricto, the previously recognized groups Yuccoideae and Agavoideae as subfamilies, appeared well delimited. The first group is associated with the South American genus Excremis (Funkiaceae) The morphological data from Excremis is not enough as to consider it within Agavaceae. At the base oftheAgaveae ciad e, Hesperaloii resulted as the sister taxon of the group, followed by the sister taxa Beschorneria and Furcraea. Finally, the group considered by authors as the tribe Agaveae formed a monophyletic clade with Agave at the base associated to Manfreda and relatives, and the sister group Polianthes and Pseudobravoa as the most derived taxa.