El estudio sistemático de Agavaceae y Nolinaceae, y Asparagales relacionados en las Monocotiledóneas: un análisis basado en la secuencia del gen rbcL

The nature and limits of the Agavaceae have been controversial since its proposition in the last century. Here we analyze the sequences of the chloroplast gene rbcL of 9 species from the Agavaceae sensu Hutchinson (1934, 1959) along with 44 additional sequences, including 36 sequences from the Lilianae, and as outgroups 8 sequences of the Alismatanae and Arecanae. We present parsirmony, neighbor-joining and maximum likelihood analysis We identified three main evolutionary lines related to the Agavaceae as defined by Hutchinson. These lines encompass most of the Asparagales order as defined by Dahlgren et al. (1985): (i)Asparagus (Asparagaceae), Dianella (Phormiaceae), Hemerocallis (Hemerocallidaceae) and the Asphodelacea (Aloe, Haworthia and Kniphofia); (ii) Agavaceae sensu stricto, including Agave, Manfreda, Beschorneria, Hesperaloe and Yucca, the Asiatic genus Hasta (Funkiaceae) and the pantropical herb Chlorophytum (Anthericaceae); (iii) Sansevieria (Dracaenaceae), Danae (Ruscaceae) and the Nolinaceae (Nolina, Beaucamea and Dasylirion). According to our analysis other groups of species related to the Agavaceae sensu Hutchinson are: Bowiea (Hyacinthaceae), ledebouria (= Sci/la, Hyacinthaceae), Clivia (Amaryllidaceae), Lomandra (Dasypogonaceae), Xanthorrhoea (Xanthorrhoeaceae), Cyanastrum (Cyanastraceae) and the lridaceae (Iris, Orthosanthus and Anomatheca). We conclude that the Agavaceae, as proposed by Hutchinson (1934, 1959) is not a monophyletic group, although most of its species form the core of a larger clade that approximately corresponds (with the addition of the Iridaceae) lo the Asparagales as proposed by Dahlgren et al. ( 1985).