ABSTRACT
Coprosma kawaikiniensis K.R. Wood, Lorence & Kiehn (Rubiaceae), a rare endemic tree from Kaua'i, Hawaiian Islands, is described and illustrated along with a previously undescribed endemic plant community, the Dubautia-Sadleria shrubland-fernland (DSSF). The new species differs from Hawai'i congeners by its combination of opposite, long, elliptic to narrowly elliptic or ovate-elliptic leaves with revolute margins; caducous stipules 7-10 mm long, externally glabrous, densely hirtellous-pilose near the margins of the inner surface; unbranched inflorescences with peduncles 20-28 mm long; flowers 6-8 per cluster; and persistent calyx tube with 4-8 irregular dentate lobes. Known only from the windward slopes and ridges of southeastern Kaua'i below the Kawaikini summit, Coprosma kawaikiniensis falls into the IUCN Critically Endangered (CR) Red List category.
ABSTRACT
The 'didymocarpoid Gesneriaceae' (traditional subfam. Cyrtandroideae excluding Epithemateae) are the largest group of Old World Gesneriaceae, comprising 85 genera and 1800 species. We attempt to resolve their hitherto poorly understood generic relationships using three molecular markers on 145 species, of which 128 belong to didymocarpoid Gesneriaceae. Our analyses demonstrate that consistent topological relationships can be retrieved from data sets with missing data using subsamples and different combinations of gene sequences. We show that all available classifications in Old World Gesneriaceae are artificial and do not reflect natural relationships. At the base of the didymocarpoids are grades of clades comprising isolated genera and small groups from Asia and Europe. These are followed by a clade comprising the African and Madagascan genera. The remaining clades represent the advanced Asiatic and Malesian genera. They include a major group with mostly twisted capsules. The much larger group of remaining genera comprises exclusively genera with straight capsules and the huge genus Cyrtandra with indehiscent fruits. Several genera such as Briggsia, Henckelia, and Chirita are not monophyletic; Chirita is even distributed throughout five clades. This degree of incongruence between molecular phylogenies, traditional classifications, and generic delimitations indicates the problems with classifications based on, sometimes a single, morphological characters.
ABSTRACT
Resupination is the orientation of zygomorphic flowers during development so that the median petal obtains the lowermost position in the mature flower. Despite its evolutionary and ecological significance, resupination has rarely been studied in a phylogenetic context. Ten types of resupination occur among the 210 species of the orchid genus Bulbophyllum on Madagascar. We investigated the evolution of resupination in a representative sample of these species by first reconstructing a combined nrITS and cpDNA phylogeny for a sectional reclassification and then plotting the different types of inflorescence development, which correlated well with main clades. Resupination by apical drooping of the rachis appears to have evolved from apical drooping of the peduncle. Erect inflorescences with resupinate flowers seem to have evolved several times into either erect inflorescences with (partly) non-resupinate flowers or pendulous inflorescences with resupinate flowers.
Subject(s)
Evolution, Molecular , Flowering Tops/genetics , Orchidaceae/anatomy & histology , Orchidaceae/growth & development , Orchidaceae/genetics , Cell Nucleus/genetics , DNA, Chloroplast/analysis , Flowering Tops/growth & development , Flowering Tops/physiology , Madagascar , PhylogenyABSTRACT
Cyrtandra comprises at least 600 species distributed throughout Malesia, where it is known for many local endemics and in Polynesia and Micronesia, where it is present on most island groups, and is among the most successfully dispersing genera of the Pacific. To ascertain the origin of the oceanic Pacific island species of Cyrtandra, we sequenced the internal transcribed spacers of nuclear ribosomal DNA of samples from throughout its geographical range. Because all oceanic Pacific island species form a well-supported clade, these species apparently result from a single initial colonization into the Pacific, possibly by a species from the eastern rim of SE Asia via a NW-to-SE stepping stone migration. Hawaiian species form a monophyletic group, probably as a result of a single colonization. The Pacific island clade of Cyrtandra dispersed across huge distances, in contrast to the apparent localization of the SE Asian clades. Although highly vagile, the Pacific clade is restricted to oceanic islands. Individual species are often endemic to a single island, characteristic of the "supertramp" life form sensu Diamond (1974, Science 184: 803-806). The evolution of fleshy fruit within Cyrtandra provided an adaptation for colonization throughout the oceanic Pacific via bird dispersal from a single common ancestor.