DAVIS, J.I.1*, D.WM. STEVENSON1,2, L. CAMPBELL2, D. GOLDMAN1, C. HARDY1,2, F. MICHELANGELI1,2, M. SIMMONS1, and C. SPECHT2. 1L.H. Bailey Hortorium, Cornell University, Ithaca, NY; 2New York Botanical Garden, Bronx, NY. - Phylogenetic relationships among the monocots, as inferred from morphology and nucleotide sequence variation in three genes.
A phylogenetic analysis of the monocotyledons was conducted, using
four character sets (morphology plus nucleotide sequences of the
plastid-encoded gene rbcL and the mitochondrion-encoded genes atpA and
cob). The taxon set comprises 58 dicot and gymnosperm outgroups, and
155 exemplar monocots, representing all major lineages of the
monocots. The deepest branch within the monocots is between a clade
that includes Acorus and all sampled elements of Alismatanae
and Aranae, and a second clade that includes all other monocots.
Within the latter group there are four lineages of Lilioids, plus a
Commelinid lineage that includes all remaining monocots. Within the
Commelinids, Arecales are sister of a clade that includes all other
members of the group. Morphological characters that contribute
substantially to the overall phylogenetic structure include
presence/absence of oxalate raphides, vessel elements in leaves, and
cell wall ferulates, plus variation in phyllotaxis, leaf venation,
stomatal type, microsporogenesis, placentation, endosperm storage
constituents, embryo form, and modification of the first tepal as a
bracteole.
Key words: atpA, cob, monocots, morphology, phylogenetics, rbcL