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The orchid flora of Cocos Island National Park, Costa Rica is described based on field collections and herbarium sampling. Cocos Island is an oceanic island situated 550 km south-west of Puntarenas (the main Costa Rican port on the Pacific coast) and 680 km north-east of the Galápagos Islands. Five species of orchids were recorded in this small area of 24 km: Camaridium micranthum and Ornithidium adendrobium (both formerly included in Maxillaria) and three endemic species of Epidendrum ( E. cocoense, E. insulanum and E. jimenezii). The species are described and analytical illustrations are provided for each. A key to the species for field identification based on morphology is presented. Biogeography, ecology, taxonomy, evolution and conservation status of the species are also discussed. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, , 20-39. [ABSTRACT FROM AUTHOR]

Speciation on islands, and particularly the divergence of species in situ, has long been debated. Here, we present one of the first, complete assessments of the geographic modes of speciation for the flora of a small oceanic island. Cocos Island (Costa Rica) is pristine; it is located 550 km off the Pacific coast of Central America. It harbors 189 native plant species, 33 of which are endemic. Using phylogenetic data from insular and mainland congeneric species, we show that all of the endemic species are derived from independent colonization events rather than in situ speciation. This is in sharp contrast to the results of a study carried out in a comparable system, Lord Howe Island (Australia), where as much as 8.2% of the plant species were the product of sympatric speciation. Differences in physiography and age between the islands may be responsible for the contrasting patterns of speciation observed. Importantly, comparing phylogenetic assessments of the modes of speciation with taxonomy-based measures shows that widely used island biogeography approaches overestimate rates of in situ speciation., (© 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.)

DNA barcoding is a technique in which species identification is performed by using DNA sequences from a small fragment of the genome, with the aim of contributing to a wide range of ecological and conservation studies in which traditional taxonomic identification is not practical. DNA barcoding is well established in animals, but there is not yet any universally accepted barcode for plants. Here, we undertook intensive field collections in two biodiversity hotspots (Mesoamerica and southern Africa). Using >1,600 samples, we compared eight potential barcodes. Going beyond previous plant studies, we assessed to what extent a "DNA barcoding gap" is present between intra- and interspecific variations, using multiple accessions per species. Given its adequate rate of variation, easy amplification, and alignment, we identified a portion of the plastid matK gene as a universal DNA barcode for flowering plants. Critically, we further demonstrate the applicability of DNA barcoding for biodiversity inventories. In addition, analyzing >1,000 species of Mesoamerican orchids, DNA barcoding with matK alone reveals cryptic species and proves useful in identifying species listed in Convention on International Trade of Endangered Species (CITES) appendixes.