María Mercedes Arbo

Phylogenetic relationships, chromosome and breeding system evolution in Turnera (Turneraceae): inferences from its sequence data

Turnera provides a useful system for exploring two significant evolutionary phenomena-shifts in breeding system (distyly vs. homostyly) and the evolution of polyploids. To explore these, the first molecular phylogeny of Turnera was constructed using sequences of the internal transcribed spacer region (ITS) of nuclear ribosomal DNA for 37 taxa. We attempted to resolve the origins of allopolyploid species using single-strand conformation polymorphism and sequencing of homeologous copies of ITS. Two allohexaploid species possessed putative ITS homeologues (T. velutina and T. orientalis). A phylogenetic analysis to identify progenitors contributing to the origins of these polyploids was unsuccessful, possibly as a result of concerted evolution of ITS. Breeding system evolution was mapped onto the phylogeny assuming distyly to be ancestral in Turnera. Self-compatible homostyly appears to have arisen independently at least three times in Turnera; however, we were not able to determine whether there have been independent origins of homostyly among hexaploid species in series Turnera. Our phylogenetic analyses suggest that series Turnera is monophyletic. Neither series Microphyllae nor Anomalae, however, appear to be monophyletic. Future taxonomic revisions may require new circumscriptions of these latter series.

Cyanohydrin glucosides of turneraceae

Abstract Cyanohydrin glucosides from Piriqueta taubatensis, P viscosa ssp. australis, Turnera angustifolia, T. caerulea, T. chamaedryfolia, T. hassleriana and Wormskioldia longipedunculata were isolated and identified. Members of the Turneraceae produce cyclopentanoid cyanohydrin glucosides as weil as linamarin. This is the first report of linamarin from the Turneraceae. Both types of 1,4-dioxygenated cyclopentanes ( cis and trans ) were represented. The relationship of the Turneraceae to the Passifloraceae and Flacourtiaceae is discussed briefly.

The major diversity centre for Neotropical Turneraceae

The Neotropical country where the Turneraceae are best represented is Brazil; 82% of the American species are native, and 73% of them are endemic to this country. The most diverse states are Bahia, Minas Gerais and Goiás. Within this area the diversity – in terms of number of species – was analysed at a level of one degree square, taking into account the phytogeographic domains (biomes) recognized in Brazil. The distribution of endemic and rare species was also explored. The major centre of diversity is located in the Chapada Diamantina, Bahia, inside the biome ‘Caatinga’, but there are hotspots in Minas Gerais and Goiás, within the biome ‘Cerrado’. The biome with highest number of endemic species is the ‘Cerrado’, followed by the ‘Caatinga’.

Identity of Schizachyrium sulcatum and S. brevifolium (Poaceae: Andropogoneae)

Schizachyrium sulcatum, distributed in Brazil, Bolivia and Colombia, is described, illustrated, and reported for the first time from Peru and Venezuela. Synonymy, geographical distribution, ecology, and a list of representative specimens examined are provided. Characters of taxonomic value are established in order to differentiate this species fromS. brevifolium. A comparative study based on morphology, leaf anatomy, and micromorphological features of the spikelets and leaf blade are included. The multivariate analysis based on morphological variables allowsS. sulcatum to be distinguished clearly fromS. brevifolium.

Anatomy, pollen, and chromosomes of Adenoa (Turneraceae), a monotypic genus endemic to Cuba

The monotypic genus Adenoa is endemic to Cuba. Its name alludes to the presence of minute glands on the petal margin, identified in the present study as lachrymiform colleters. Here we describe the morphological, anatomical, palynological, and chromosome features that characterize Adenoa cubensis. The indumentum of Adenoa consists only of stellate trichomes. Unlike many species of the new world genera Piriqueta and Turnera, Adenoa lacks glandular hairs and extrafloral nectaries. Adenoa, Piriqueta, and Turnera share the presence of standard, sessile, and lachrymiform colleters. The leaves of Adenoa have xeromorphic features, which include entire, revolute blade margins, an adaxial hypodermis, and stomata restricted to the abaxial surface. The chromosome number is 2n = 14, which is probably the ancestral number of the family. Adenoa chromosomes are similar in size to those of Turnera, and are larger than those of Piriqueta. Using the available data, we discuss relationships among the new world genera of Turneraceae.