| Abstract Detail
Systematics/Phytogeography / Taxonomie/ Section Tate, Anthony [1], Carlsward, Barbara S. [1], Whitten, W. M. [2]. Perianth anatomy of Maxillaria and related genera (Orchidaceae). As traditionally circumscribed, Maxillaria is a large orchid genus found throughout the American tropics and subtropics. Â Recent molecular phylogenetic analyses show that Maxillaria sensu lato is polyphyletic, and core Maxillariinae have been redefined to include 17 monophyletic genera. Â The focus of our study was to find anatomical features within the perianth that could be used to diagnose the newly defined clades of Maxillariinae currently based on molecular data. Â Transverse sections of petals were made at 90 μm using a sliding microtome, stained with iron-alum haematoxylin and safranin, and mounted on microscope slides. Â In transverse section, all petals of Maxillaria sensu stricto contain at least some scattered, homogeneous fiber bundles, making their presence a potential diagnosable feature of the clade. Â Fiber bundles are absent in most other genera, except Rhetinantha. Â However, fiber bundles of Rhetinantha are heterogeneous and restricted to the ad- and abaxial surfaces. Â Other distinct anatomical features found in Maxillariinae are scattered, sclerified idioblasts and mucilage-containing ground tissue. Â Sclerified idioblasts are abundant in Heterotaxis, Rhetinantha, and Maxillaria. Â Camaridium, Trigonidium, and some species of Maxillaria possess ground tissue with large amounts of mucilage. Â In Maxillaria, these mucilage-containing cells are restricted to a few adaxial layers just below the epidermis. Â From the anatomical features examined in our study, fiber bundles seem to be the most useful in diagnosing the genera of Maxillariinae. Log in to add this item to your schedule
Related Links: Phylogenetics of Maxillariinae (Orchidaceae)
1 - Eastern Illinois University, Department of Biological Sciences, 600 Lincoln Avenue, Charleston, IL, 61920, USA 2 - University of Florida, Florida Museum of Natural History, Gainesville, Florida, 32611-7800, USA
Keywords: petals anatomy Maxillaria fiber bundles sclerified idioblasts mucilage phylogenetics.
Presentation Type: Poster:Posters for Sections Session: P Location: Ball Room & Party Room/SUB Date: Monday, July 28th, 2008 Time: 12:30 PM Number: PSP061 Abstract ID:743 |