Molecular Data and Systematics of genera and species of Laeliinae
by Cassio van den Berg


In order to evaluate generic alliances in Laeliinae and relationships to select outgroups in Epidendreae, we gathered the datasets. Although relationships between Laeliinae and outgroups were well-suported, within the subtribe sequence variation was small, considering the broad taxonomic range studied. In both plastide and nuclear phylogenies many branches collpased and only a few are well-supported. The sister group of Laeliinae is shown to be Arpophyllum, Pleurothallidinae, Ponerinae. The phylogeny within the Cattleya alliance is clarified, suggesting that previous ITS data contained some paralogous sequences. DNA data allow proposing new generic alliances, and redefining species delimitation.

Cassio van den Berg is professor at the University of Feira, State of Bahia, Brazil.

Why does my orchid have more than one name?
by Gary Yong Gee & Roger Sawkins


When orchids were initially classified the morphology of the flowers, and to some extent the plant, were the main characteristics used. Recent analysis of DNA sequence data has been used to better show the relationships between genera, particularly whether common or different ancestors are involved. Nowadays taxonomists look towards classifying species in monophyletic rather than paraphyletic genera.
Large genera such as Dendrobium, Bulbophyllum, Laelia and Oncidium have had numerous species included based upon floral morphology. Analysis of DNA sequence data shows that many genera are paraphyletic, so taxonomists have been reclassifying the species. Individuals however may interpret the DNA sequence data differently. This has resulted in numerous changes to the generic names of many of the species grown in cultivation.
In recent years authors such as Mark Clements, David Jones and Dariusz Szlachetko, as well as Mark Chase and Cassio van den Berg have published changes to a large number of species. However authors such as Stephen Hopper and Andrew Brown, as well as Guy Chiron and Vitorino Castro have challenged some of these changes and published others of their own.
The speaker illustrated many of the changes with photographs and discuss the advantages and disadvantages of the new classifications. He will also discuss the issues which face growers and hybridizers when the names of some species do not remain static.

Gary Yong Gee has been a judge for many years. He has over 30.000 photographs of orchid species and has traveled to many parts of the world. He writes for the Orchid Species Bulletin each month and is co-author of the Cd rom Orchidopedia.

Unexpectedly Diverse Mycorrhizal Symbionts In European Forest Green Orchids (Neottieae) Suggests A Partial Mycoheterotrophy
by Marc-André Selosse


Achlorophyllous mycoheterotrophic orchids (MHOs) reverse the usual mycorrhizal symbiosis (where plants exchange photosynthates against mineral nutrients) by recovering carbon from the fungus. MHOs evolved at several times by shifting from usual orchid rhizoctonia partners to other basidiomycetes forming ectomycorrhizae (ECM) with trees. MHOs are specific to narrow fungal clades that are mycorrhizal with surrounding green plants, which provide carbon to both heterotrophs.
We investigated symbionts of chlorophyllous species phylogenetically related to MHOs from the forest orchid tribe Neottieae, that includes MHOs like Neottia nidus-avis or Cephalanthera austiniae, and photosynthetic species, e.g. in the genera Limodorum, Epipactis and Cephalanthera. Root symbionts were identified by ITS amplification and sequencing. Limodorum abortivum is rather specifically associated to Russulaceae, but may contain additional ascomycetes; in addition, photosynthesis experiments suggested that this orchid, although photosynthetic, needs a carbon flux from the fungus. We also studied symbiont diversity in three Epipactis and two Cephalanthera species from European populations, including several achlorophyllous and subterranean individuals. An unexpected fungal diversity was found, including various basidiomycetes such as Sebacinaceae, Thelephoraceae, Russulaceae… as well as Ascomycetes belonging to Helotiales, Pezizaceae (e.g. truffles – Tuber sp.). Ascomycetes were confirmed to form pelotons within orchid root cells by TEM analysis. These orchids are therefore low specificity associates of ECM fungi. Since green orchids have symbionts similar to the achlorophyllous and subterranean individuals, which are mycoheterotrophic, some green Neottieae could partly behave as MHOs. Isotopic data obtained on a Cephalanthera damasonium population suggests that both achlorophyllous and green individuals mainly rely on fungal carbon for their growth.
Among Neottieae, ECM symbionts perhaps replaced the Rhizoctonias as these orchid shifted to forest niches, possibly as an adaptation to low-light habitats. We speculate that this entailed a predisposition to mycoheterotrophy by exploitation of tree photosynthates.

Marc-André Selosse is Master of Conferences at Paris VI University and leading the research "Systématique, Adaptation et Evolution" (Sistematic, Adaptation and Evolution) at the Natural History Museum.

Movements of The Flowers and Sexuality in Orchids
by Albert Roguenant


The concept of respiration which supposes that the orchid flower moves on a 180° angle appears obsolete. We observed that – the lip orientates either downward or upward – the symmetry plane orientates vertical – the flower plane orientates tangential to the inflorescence envelope. We propose the following terminology : the orientating movements of the flower, as a whole, correspond to the gyration – the flower having its lip orientated upward is said epigeous– in the opposite case it is said hypothyroid. This phenomenon probably extends to other families of hygroscopic flowered flowering plants.
We observe several other types of movements not indicated by authors. We will show that the 180° angle is but a particular case.
We have recorded several movements leading to fit the flower to a given orientation :
- large range movements:
- the pedicel and/or the ovary is twisted
- bending of the pedicel and/or of the ovary;
- complementary movements, of small range
- various movements drawing the flower to fit to its optimal position related to 1) vertical and 2) the inflorescence envelope.

Albert Roguenant works with the floral biology of orchids. He is the co-author of a book on orchids pollinator, recently published.

Species and phylogeny in orchids
by Daniel PRAT


The number of described orchid species increases since several decades. Hybrids between taxa identified by morphological traits as species or even genera are observed. This means probably that systematics needs reassessment
of taxon ranks. The species concept has got several definitions in plants (Judd et al., 1999); the genetic isolation of species remains the most suitable concept. The development of genetics should help botanists in the description of taxa with a proper rank. Most recent studies dealt with phylogeny. With phylogenetic approaches, genetic relationships between taxa
are established, more or less precisely, according to the set of taxa and to the genetic markers used. As the radiation of some genera like Ophrys, Epipactis. occurred recently, few genetic changes can be found in the sequences used for phylogenetic studies (Pridgeon et al., 1997; Soliva et al., 2001; Bernadinos et al, 2004). The genetic proximity of taxa does not mean they belong or not to the same species. Genetic isolation of taxa should be considered. Gene flows are investigated to determine whether taxa exchange genes (Soliva and Wildmer, 2003). The low genetic structure observed at the species levels reveals pollination among taxa even if specific pollinators are presumed. Relationships between Ophrys gresivaudanica and the close taxon Orchis fuciflora will be presented. Conclusions on the interactions between phylogenetic and systemactics considerations will be drawn.

Professor Daniel PRAT is the director of the Higher Plant Genome and Evolution Lab, Biology Department, University Claude Bernard, Lyon (France) In charge of the Scientific Commission of the French Orchid Society (SFO)




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