Abstract Detail

Systematics Section / ASPT

Alford, Mac H. [1].

Phylogeny and Classification of the Flacourtiaceae/Salicaceae Complex.

Until recently, the family Flacourtiaceae consisted of 79-95 genera and about 800-1200 species. The family was morphologically diverse and hard to characterize, in part because it served as a depository for taxa with unknown affinities. Recent phylogenies drawn from DNA sequence data have affirmed the polyphyletic nature of the family, and a taxonomic rearrangement has been proposed which splits Flacourtiaceae into two major families, Achariaceae and Salicaceae, and excludes a small number of unrelated taxa. Presented here is a more robust phylogeny of one of these families, the Salicaceae sensu lato, which includes Salicaceae sensu stricto (willows, poplars, and cottonwoods), Scyphostegiaceae, and the majority of the former Flacourtiaceae (>80% of the species). Phylogenetic relationships were inferred from morphological data gathered for all genera and chloroplast DNA sequence data (trnL-F, 3' end of ndhF) gathered for 86% of the genera. This represents a significant increase in the numbers of taxa and characters sampled. A new classification is proposed based on this phylogeny that optimizes morphologically homogeneous groups. Samydaceae are resurrected as a family, Scyphostegiaceae are maintained as traditionally circumscribed, and a modified but more homogeneous Salicaceae, including only the "salicoid" Flacourtiaceae, are introduced. The distribution of character states for seed appendages, leaf teeth types, anther dehiscence, and pellucid-punctations corresponds well with this system. The phylogeny also provides insights into the evolution of the reduced flowers and inflorescences of Salix and Populus. It suggests that flowers lacking perianth first lost petals and then sepals and that the catkins evolved by reduction and congestion of racemes or panicles of cymes. This scenario is further supported by recent fossil discoveries. Presence of disc glands in the sister genera also indicates that the nectaries of Salix are probably homologous to disc glands instead of perianth or de novo emergences.

1 - Cornell University, L.H. Bailey Hortorium, Department of Plant Biology, Ithaca, New York, 14853, U.S.A.

Keywords:
Flacourtiaceae
Salicaceae
Scyphostegiaceae
Samydaceae
Classification
amentifery
nectaries
trnL-F
ndhF.

Presentation Type: Paper
Session: 30-8
Location: Cottonwood B (Snowbird Center)
Date: Tuesday, August 3rd, 2004
Time: 10:00 AM
Abstract ID:599