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Systematics Section / ASPT

Kiel, Carrie A. [1], Daniel, Thomas F. [2], McDade, Lucinda A. [1].

Phylogenetic Relationships within the Subtribe Isoglossinae (Acanthaceae).

Isoglossinae are a subtribe of the wide ranging and taxonomically difficult tribe Justicieae (Acanthaceae).  With an estimated 200 species, in about 14 genera and a distribution that includes tropical and subtropical parts of the Americas, Africa and SE Asia, Isoglossinae are characterized as having 2 stamens with mono or dithecous anthers and "Gurtelpollen" (i.e. girdled pollen) as morphological synapomorphies.  Interestingly, Ptyssiglottis, which is placed basally in the group by our earlier analysis, is the exception in having 4 stamens and a diversity of pollen types.  Presumably associated with pollinator relationships, the plants have diverse floral morphological characters including several groups with remarkably showy hummingbird flowers in the New World.  Old World genera of Isoglossinae include African Brachystephanus, Isoglossa, Oreacanthus; Malagasy Conocalyx, Populina, and Sphacanthus; and SE Asian Ptyssiglottis. New World Isoglossinae have been treated as belonging to a number of poorly-delimited genera, including Cylindrosolenium, Habracanthus, Hansteinia, Kalbreyeiella, Razisea, and  Stenostephanus.  With a nearly complete sample at the genus level and multiple species to represent the larger genera, we have examined this group using data from DNA sequences and morphology to address the following questions:  (1) Is Ptyssiglottis supported as the basal member of Isoglossinae with the addition of data from the rps16 and trnG,S spacers? (2) Can morphological evidence be found to support the placement of Ptyssiglottis with the crown group of Isoglossinae? (3) Are the Old World and New World groups reciprocally monophyletic?  Evidence shows that the NW lineage is monophyletic whereas OW Isoglossinae are paraphyletic. (4) Are the NW genera monophyletic as traditionally delimited?  Our results show that several of the smaller genera (e.g., Razisea, Kalbreyeriella) were likely derived from within the larger genera such that generic limits require extensive revision.

1 - Academy of Natural Sciences, Botany, 1900 Ben Franklin Parkway, Philadelphia, Pennsylvania, 19103, USA
2 - California Academy of Sciences, Botany, Golden Gate Park, San Francisco, California, 94118, USA

rps16 intron
trnS-G intergenic spacer
molecular sequences.

Presentation Type: Poster
Session: 32-113
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM
Abstract ID:303

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