Bente B. Klitgaard

Phylogenetic Relationships in the Caesalpinioideae (Leguminosae) as Inferred from Chloroplast trnL Intron Sequences

Abstract The basal subfamily Caesalpinioideae of the Leguminosae generally is subdivided into four or five tribes, but their monophyly remains questionable. Recent cladistic analyses based on morphological characters and chloroplast rbcL sequences suggest conflicting hypotheses of relationships among tribes and subtribal groupings and of the identification of the basal Caesalpinioideae. Our phylogenetic analysis of the chloroplast trnL intron for 223 Caesalpinioideae, representing 112 genera, plus four Papilionoideae, 12 Mimosoideae and three outgroup taxa, provides some well-supported hypotheses of relationships for the subfamily. Our analysis concurs with the rbcL studies in suggesting that a monophyletic Cercideae is sister to the remainder of the Leguminosae. Among the other tribes of Caesalpinioideae, only the broadly circumscribed Detarieae (including Amherstieae or Macrolobieae) is also supported as monophyletic. The Detarieae s.l. occurs as sister to all Leguminosae, excluding Cercideae. Cassieae subtribes Dialiinae and Labicheinae together are sister to the remaining Leguminosae, which includes a monophyletic Papilionoideae, a paraphyletic Mimosoideae, and several monophyletic groups that correspond to previously defined generic groups or subtribes in the Caesalpinioideae. The trnL intron analysis suggests that basal legumes are extremely diverse in their floral morphology, and that presence of simple, actinomorphic flowers may be a derived feature in a number of lineages in the family. Communicating Editor: Matt Lavin

Contrasting plant diversification histories within the Andean biodiversity hotspot

The Andes are the most species-rich global biodiversity hotspot. Most research and conservation attention in the Andes has focused on biomes such as rain forest, cloud forest, and páramo, where much plant species diversity is the hypothesized result of rapid speciation associated with the recent Andean orogeny. In contrast to these mesic biomes, we present evidence for a different, older diversification history in seasonally dry tropical forests (SDTF) occupying rain-shadowed inter-Andean valleys. High DNA sequence divergence in Cyathostegia mathewsii, a shrub endemic to inter-Andean SDTF, indicates isolation for at least 5 million years of populations separated by only ca. 600 km of high cordillera in Peru. In conjunction with fossil evidence indicating the presence of SDTF in the Andes in the late Miocene, our data suggest that the disjunct small valley pockets of inter-Andean SDTF have persisted over millions of years. These forests are rich in endemic species but massively impacted, and merit better representation in future plans for science and conservation in Andean countries.

Phylogenetic Relationships of Basal Papilionoid Legumes Based Upon Sequences of the Chloroplast trnL Intron

Abstract The Swartzieae, Sophoreae, Dipterygeae, and Dalbergieae are considered the most basal tribes of the subfamily Papilionoideae (Leguminosae). Nucleotide sequences from the chloroplast trnL intron for the majority of genera of these tribes were analyzed cladistically together with placeholder representatives of more derived tribes. Preliminary results indicate radical changes are necessary for papilionoid classification because Swartzieae, Sophoreae, and Dalbergieae are polyphyletic. Their constituent genera are mixed in a series of monophyletic groups, many of which have never been proposed previously, and the relationships amongst which are poorly resolved. Some of these groups, such as the genistoid and dalbergioid clades, are species-rich because they contain major papilionoid radiations. In other cases, putatively basal genera form small clades with no derived taxa included. There is weak evidence that Bobgunnia, Swartzia, Cyathostegia, Bocoa, and Ateleia (all Swartzieae) may be the sister group to all other papilionoids, and that a large clade is congruent with a 50kb inversion in the chloroplast large single copy (LSC) region. Communicating Editor: Kathleen A. Kron

Acacia: The case against moving the type to Australia

Recent studies have shown that Acacia is polyphyletic and must be split into five genera. Proposal 1584 would retypify Acacia : the type of the Australian taxon A. penninervis would be conserved over the current lectotype ( A. scorpioides ) of an African taxon. We disagree with the recommendation of the Spermatophyte Committee to endorse this proposal. Contrary to Article 14.12 of the ICBN, no detailed case against conservation was presented in Proposal 1584. We maintain that there are strong arguments against conservation, such as the large number of countries that would be affected, the economic importance of the extra-Australian species, and the economic burden placed on developing countries. Acceptance of this proposal would also violate the guidelines for conservation which clearly state that the principle of priority should prevail when conservation for one part of the world would create disadvantageous change in another part of the world.

Revision and Biogeography of Centrolobium (Leguminosae - Papilionoideae)

Abstract A taxonomic revision and biogeographic study of the genus Centrolobium (Leguminosae - Papilionoideae) is presented. Centrolobium includes important timber trees distributed disjunctly in seasonally dry tropical forests and rain forests in Central and South America, from Panama to south-eastern Brazil. It is characterized by large samaroid pods with a spiny seed case and an abundance of orange peltate glands covering the leaves and inflorescences. Taxonomic distinctions between some species of Centrolobium have been a source of confusion. Here, seven species are recognized: C. robustum, C. microchaete, C. tomentosum, C. ochroxylum, C. sclerophyllum, C. paraense, and C. yavizanum. Previously recognized varieties of C. paraense, C. paraense var. paraense and C. paraense var. orinocense, are not maintained. Phylogenetic analysis of DNA sequence data from the internal transcribed spacer region of nuclear ribosomal DNA and the plastid matK gene and trnL-trnF intron and spacer support the monophyly of the genus. Different molecular dating methods indicate that the Centrolobium crown group and lineages found to the west and east of the Andes diverged before the Pleistocene. Divergences between species occurring east of the Andes, particularly in Bolivia and south-eastern Brazil are more recent, but nevertheless unlikely to be explained by Pleistocene climatic changes.

FLORAL EVOLUTION IN THE DETARIEAE (LEGUMINOSAE): PHYLOGENETIC EVIDENCE FOR LABILE FLORAL DEVELOPMENT IN AN EARLY-DIVERGING LEGUME LINEAGE

Premise of research. We examine floral evolution and phylogenetic relationships in the monophyletic Detarieae and related lineages of Caesalpinioideae. Tribe Detarieae (82 genera) includes nearly half of the genera in subfamily Caesalpinioideae and represents some of the most diverse legumes with respect to floral morphology. Methodology. A total of 67 floral ontogenetic and morphological characters were combined with DNA sequences from the plastid trnL-F and matK regions of 34 Detarieae species and representatives of Cassieae, Cercideae, Caesalpinieae, Papilionoideae, and Mimosoideae, for which we have near-complete ontogenetic series. The morphological and ontogenetic characters were optimized onto the resulting most parsimonious phylogenetic trees and Bayesian topology to study character evolution. Pivotal results. Our study supports previously proposed relationships within the tribe Detarieae and among caesalpinioid lineages and indicates that certain features (bracteole and hypanthium characters, sepal initiation, anther position in bud, overlap in timing of initiation of organ whorls) are phylogenetically informative for particular clades whereas others (reductions in petal and stamen number, sepal and petal initiation patterns) have evolved multiple times in parallel in the Detarieae and other Caesalpinioideae. These analyses suggest that modifications that occur early in ontogeny can be good phylogenetic characters for distinguishing both major taxonomic groups and more closely related taxa and that morphological differences that differentiate species within genera can be caused by changes that occur at all stages of ontogeny. Phylogenetic distribution of character states and ontogenetic evidence suggest that in the Caesalpinioideae, loss or suppression of organs within a whorl, both of which are very common, usually does not affect development in subsequent whorls. Conclusions. Our analyses reveal several switches from zygomorphy to actinomorphy (and vice versa), but in Caesalpinioideae (contrary to Papilionoideae), zygomorphy is likely not clearly associated with higher diversification rates. This study suggests that floral initiation patterns are much more variable in Caesalpinioideae than in the other two subfamilies. Although particular patterns may be canalized in certain lineages of the subfamily (Cercideae, Caesalpinieae), in other clades (Detarieae, Dialiinae) floral development is more labile, explaining the high diversity in floral morphology encountered overall in the paraphyletic Caesalpinioideae.

The genus Machaerium (Leguminosae: Papilionoideae: Dalbergieae) in Ecuador

The Amphiatlantic genusMachaerium consists of shrubs, trees, and lianas occurring from sea level to 500–900 m (rarely 1700 m). The genus is known from Mexico southward to Brazil and Argentina, with one species (M. isadelphum) extending to Trinidad and Tobago, and another species (M. lunatum) to the west coast of Africa. Of the estimated 130Machaerium species, eleven species and three varieties are known from Ecuador. Four of these thirteen taxa are widely distributed in Central and South America. The remaining nine taxa are distributed from Venezuela to Brazil, with one species,M. quinatum, reaching Argentina. Three species and three varieties are here presented as new records for Ecuador. General morphology, taxonomic treatments with keys to species, descriptions, illustrations, and maps of all Ecuadorian species are provided.ResumenEl género amfiatlánticoMachaerium (Papilionoideae-Dalbergieae) consiste de lianas, arbustos o árboles en tierras bajas desde el nivel del mar hasta los 500–900 m (rara vez 1700 m). El género está distribuido desde México hasta Brasil y Argentina, con una especie,M. isadelphum que crece en las islas de Trinidad y Tobago, y otra en la costa oeste de África (M. lunatum). De las estimadas 130 especies, once especies y tres variedades se encuentran en Ecuador. Cuatro de estas trece taxa tienen una amplia distribución, desde Meso-América hasta Sur América, mientras que las nueve restantes están distribuidas desde Venezuela hasta Brasil con una especie que llega hasta Argentina,M. quinatum. De las especies y variedades ecuatorianas, tres especies y tres variedades se consideran nuevos registros para el país. Se discute la morfología general, además se incluye el tratamiento taxonómico con claves, descripciones, ilustraciones y mapas de distribución de todas las especies del Ecuador. Palabras clave: Amfiatlántica, claves, Ecuador, ilustraciones,Machaerium, taxonomía.

Drimia cochlearis (Hyacinthaceae), a New Species from South Africa

Abstract A new species of Drimia is here described from South Africa. Drimia cochlearis sp. nov. is at first sight closely related to both Drimia ciliata and D. sclerophylla, but it differs in a number of floral and vegetative characters that clearly support its recognition as a distinct species. Here we provide a detailed morphological description for this species, including ecological and chorological data. Affinities and divergences with close allies are also discussed.