Malpighiales phylogenetics: Gaining ground on one of the most recalcitrant clades in the angiosperm tree of life.

Department of Botany, Smithsonian Institution, P.O. Box 37012 NMNH MRC-166, Washington, District of Columbia 20013-7012 USA.
American Journal of Botany (Impact Factor: 2.46). 08/2009; 96(8):1551-70. DOI: 10.3732/ajb.0800207
Source: PubMed

ABSTRACT The eudicot order Malpighiales contains ∼16000 species and is the most poorly resolved large rosid clade. To clarify phylogenetic relationships in the order, we used maximum likelihood, Bayesian, and parsimony analyses of DNA sequence data from 13 gene regions, totaling 15604 bp, and representing all three genomic compartments (i.e., plastid: atpB, matK, ndhF, and rbcL; mitochondrial: ccmB, cob, matR, nad1B-C, nad6, and rps3; and nuclear: 18S rDNA, PHYC, and newly developed low-copy EMB2765). Our sampling of 190 taxa includes representatives from all families of Malpighiales. These data provide greatly increased support for the recent additions of Aneulophus, Bhesa, Centroplacus, Ploiarium, and Rafflesiaceae to Malpighiales; sister relations of Phyllanthaceae + Picrodendraceae, monophyly of Hypericaceae, and polyphyly of Clusiaceae. Oxalidales + Huaceae, followed by Celastrales are successive sisters to Malpighiales. Parasitic Rafflesiaceae, which produce the world's largest flowers, are confirmed as embedded within a paraphyletic Euphorbiaceae. Novel findings show a well-supported placement of Ctenolophonaceae with Erythroxylaceae + Rhizophoraceae, sister-group relationships of Bhesa + Centroplacus, and the exclusion of Medusandra from Malpighiales. New taxonomic circumscriptions include the addition of Bhesa to Centroplacaceae, Medusandra to Peridiscaceae (Saxifragales), Calophyllaceae applied to Clusiaceae subfamily Kielmeyeroideae, Peraceae applied to Euphorbiaceae subfamily Peroideae, and Huaceae included in Oxalidales.

1 Follower
  • [Show abstract] [Hide abstract]
    ABSTRACT: Rinorea is a pantropical genus of shrubs and small trees within the family Violaceae. The genus is particularly diverse in Africa where species are ecologically important as they are often abundant or even dominant in particular forest types and act as larval host plants for highly specialized Cymothoe butterflies. Despite their importance, species identification of African Rinorea is difficult and a taxonomic revision is needed. Previous phylogenetic studies have suggested that neotropical taxa are sister to a palaeotropical clade, with multiple independent dispersals to Madagascar, but these were based on plastid data only. We therefore present an updated phylogeny of Rinorea with increased sampling of African taxa, using plastid as well as nuclear DNA sequences. Phylogenetic relationships inferred from nuclear DNA data were generally congruent with those based on evidence from plastid haplotypes from earlier studies. Our increased taxonomic sampling also revealed previously undiscovered African Rinorea clades, some of which warrant further taxonomic study. Ancestral state reconstructions refute previous hypotheses about the evolution of morphological characters traditionally used for Rinorea infrageneric classification. In addition, some widespread species may comprise species complexes. It is clear that African Rinorea require comprehensive taxonomic revision; our contribution to understanding Rinorea infrageneric relationships will facilitate this task.
    Systematic Botany 02/2015; 40(1):174-184. DOI:10.1600/036364415X686486 · 1.11 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Euphorbiaceae s. str. and Phyllanthaceae were earlier components of Euphorbiaceae. This separation was mainly based on molecular data and also on morphological characteristics. Nevertheless, the structure and development of fruits are poorly investigated in these families and considering this, fruits (pericarp and seed) of Euphorbia hyssopifolia L., Croton glandulosus L. (Euphorbiaceae), Phyllanthus niruri L. and Phyllanthus tenellus Roxb. (Phyllanthaceae) were structurally studied to see in what respects they are similar or different. The Euphorbiaceae schizocarps present two meristems (adaxial and subadaxial) in the ovary wall, but the adaxial meristem is entirely lacking in Phyllanthus fruits. The seeds have an exotegmen with Malpighian palisade cells in Euphorbiaceae species and a short palisade in Phyllanthus. Some special structural features, such as nucellar beak, anatropous ovules and schizocarp fruits were found in all the species and constitute a unique combination. From the present results, it appears that there is no significant difference in fruit and seed development between the studied Euphorbiaceae and Phyllanthaceae.
    Plant Systematics and Evolution 05/2013; 300(5):775-782. DOI:10.1007/s00606-013-0918-3 · 1.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pollen development is examined in Medusagyne oppositifolia, a critically endangered tree endemic to the Seychelles. Formerly placed in its own family, M. oppositifolia is now assigned to Ochnaceae in Malpighiales. Pollen and tapetal characters have previously been shown to be of systematic importance in Malpighiales. The pollen of M. oppositifolia has remarkable projecting porate apertures, but their development was previously unknown. Pollen development was studied using transmission electron microscopy (TEM) of sections of anthers obtained from buds of cultivated M. oppositifolia. Amorphous endexine is deposited without the involvement of lamellae, a rare form of endexine deposition in flowering plants. This flexible endexine is pushed into position inside the atria (apertural cavities) by the expanding intine. Foot layer, not endexine, is deposited on lamellations with white lines, which is highly unusual. Extremely large onci, consisting of fibrillar spacer material, begin development during the tetrad stage and are located between the extexine and developing endexine in immature microspores, forming the atria. The secretory tapetum produces many orbicules (sporopollenin bodies). Pollen development in M. oppositifolia shows some highly unusual features. Despite this, it does share some characters with other Malpighiales. Similar endexine occurs in Passiflora (Passifloraceae) and similar orbicules in Populus (Salicaceae). A lamellated foot layer may also occur in Ochna (Ochnaceae), though this requires further study.
    International Journal of Plant Sciences 09/2014; 175(7):803-813. DOI:10.1086/676984 · 1.69 Impact Factor


Available from