The diverse flowers of Orchidaceae are the result of several major morphological transitions, among them the most studied is the differentiation of the inner median tepal into the labellum, a perianth organ key in pollinator attraction. Type A peloria lacking stamens and with ectopic labella in place of inner lateral tepals are useful for testing models on the genes specifying these organs by c...

Nonphotosynthetic cells of higher plants depend on the supply of a carbon substrate, usually sucrose, for cellular metabolism. Typically this sucrose is synthesized in leaves from the products of photosynthesis. Because of the lack of light below ground, roots do not generally photosynthesize (we note the exception of certain mangrove species and members of the Orchidaceae), although many roots...

Molecular systematic research, using DNA sequences of the internal transcribed spacer (ITS) region of the 18-26S nuclear ribosomal repeat unit, was conducted on a broadly representative sample of the tribe Dendrobieae. The results provide independent support, in addition to evidence from plastid DNA analysis and morphology, for the phylogenetic reassessment of the taxon. At a broad level, Dendr...

Original Article Genetic Diversity in Cypripedium calceolus (Orchidaceae) with a Focus on Northwestern Europe, as Revealed by Plastid DNA Length Polymorphisms MICHAEL F. FAY, RUTH BONE, PETER COOK, IMALKA KAHANDAWALA , JENNIFER GREENSMITH, STACEY HARRIS, HENRIK Æ. PEDERSEN, MARTIN J. INGROUILLE and CHRISTIAN LEXER 4 Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3DS, UK, Birkbeck, University ...

The center of diversity of Argentinean orchids is in the northeast region of the country. Chromosome numbers and karyotype features of 43 species belonging to 28 genera are presented here. Five chromosome records are the first ones at the genus level; these taxa are Aspidogyne kuckzinskii (2n = 42), Eurystyles actinosophila (2n = 56), Skeptrostachys paraguayensis (2n = 46), Stigmatosema polyade...

BACKGROUND AND AIMS The two closely related subtribes Bifrenariinae Dressler and Maxillariinae Benth. are easily distinguished on morphological grounds. Recently, however, molecular techniques have supported the inclusion of Bifrenariinae within a more broadly defined Maxillariinae. The present paper describes the diverse labellar micromorphology found amongst representatives of Bifrenariinae (...