Labellar Micromorphology of Bifrenariinae Dressler (Orchidaceae)

Abstract

The labella of Bifrenaria spp. and Mormolyca spp. are densely pubescent but those of Xylobium, Teuscheria and Rudolfiella are generally papillose. However, whereas the trichomes of Bifrenaria and Mormolyca are unicellular, those found in the other three genera are multicellular. Hitherto, no unicellular trichomes have been described for Maxillaria, although the labella of a number of species secrete a viscid substance or bear moniliform, pseudopollen-producing hairs. Moniliform hairs and secretory material also occur in certain species of Xylobium and Teuscheria and these genera, together with Maxillaria, are thought to be pollinated by stingless bees (Meliponini). Differences in the labellar micromorphology of Bifrenaria and Mormolyca are perhaps related to Euglossine- and/ or bumble bee-mediated pollination and pseudocopulation, respectively. Although Xylobium and Teuscheria share a number of labellar features with Maxillaria sensu stricto, this does not necessarily reflect taxonomic relationships but may be indicative of convergence in response to similar pollinator pressures.

Osmophore structure and phylogeny ofCirrhaea(Orchidaceae, Stanhopeinae)

“…(Pansarin et al ., ), C. dependens (Pansarin et al ., ) and Vanilla edwallii Hoehne (Pansarin, Aguiar & Pansarin, ). Davies & Stpiczyńska (, , , and ) also studied the anatomy of the secretory structures of Brazilian orchids, but with a greater focus on Oncidiinae and Maxillarinae.…”

Structure and distribution of floral trichomes in Lycaste and Sudamerlycaste (Orchidaceae: Maxillariinae s.l.)

“…The uniseriate, multicellular, unbranched trichomes with pointed, rounded or clavate tips closely resemble those of other members of Maxillariinae s.l. (Davies & Winters, 1998; Davies et al ., 2003b; Davies & Turner, 2004; Davies & Stpiczyńska, 2006, 2008b). Of the other taxa currently assigned to this subtribe, hairs with unequal Y‐type branching are hitherto known only to occur in Scuticaria , in particular, euglossine‐pollinated S. steelii (Lindl.)…”

“…The labellar micromorphology of Maxillariinae s.l. (excluding Lycastinae, but including former Bifrenariinae Dressler, Xylobium and Scuticaria Lindl) has been studied extensively in recent years (Davies & Winters, 1998; Davies, Winters & Turner, 2000; Davies, Turner & Gregg, 2003a, b; Davies & Turner, 2004; Matusiewicz, Stpiczyńska & Davies, 2004; Davies & Stpiczyńska, 2006, 2007, 2008a, b; Davies, 2009). In this article, we extend our studies to Lycastinae and compare the trichome distribution and micromorphology of Lycaste and Sudamerlycaste flowers to further distinguish taxonomic characters.…”

Anatomy of the floral nectary of ornithophilousElleanthus brasiliensis(Orchidaceae: Sobralieae)

“…Over the last 20 years, a series of studies has investigated the anatomy of floral glands in orchids and their relevance to pollination. Among the glands described to date are: elaiophores and osmophores (Stpiczyńska, Davies & Gregg, ; Aliscioni et al ., ; Davies & Stpiczyńska, ; Pansarin, Castro & Sazima, ), secretory trichomes (Davies & Stpiczyńska, ), spur‐shaped nectaries (Figueiredo & Pais, ; Galetto, Bernardello & Rivera, ; Stpiczyńska, Davies & Gregg, ), nectariferous flower surfaces (Stpiczyńska, Davies & Gregg, ) and other lip structures (Galetto et al ., ; Davies, Stpiczyńska & Gregg, ). Studies describing nectariferous glands in ornithophilous orchids are rare and the diversity of these nectaries indicates that they may have originated from a number of floral structures.…”