Glossary of pollen and spore terminology

The fossil record for angiosperm pollen types which are comparable to recent taxa is evaluated, following a similar survey published in 1970. Special attention is paid to the dating of the sediments. Evidence for 139 families is considered to be reliable, for others the records are cited as provisional, pending the accumulation of more evidence. Some published records are shown to be erroneous.

Fossil pollen records of extant angiosperms.

The Bases of Angiosperm Phylogeny: Palynology

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.

Malpighiales Phylogenetics: Gaining Ground on One of the Most Recalcitrant Clades in the Angiosperm Tree of Life

Parsimony and Bayesian analyses of plastid rbcL and trnL-F DNA sequence data of the pantropical family Euphorbiaceae sensu stricto (s.s.) are presented. Sampling includes representatives of all three subfamilies (Acalyphoideae, Crotonoideae, and Euphorbioideae), 35 of 37 tribes and 179 of the 247 genera of uniovulate Euphorbiaceae sensu lato (s.l.). Euphorbiaceae s.s. were recovered as a monophyletic group with no new adjustments in circumscription. Two clades containing taxa previously placed in Acalyphoideae are found to be successive sisters to all other Euphorbiaceae s.s. and are proposed here at subfamilial rank as Peroideae and Cheilosoideae. The remainder of the family fall into seven major lineages including Erismantheae and Acalyphoideae s.s. (parts of Acalyphoideae), Adenoclineae s.l., Gelonieae, articulated crotonoids and inaperturate crotonoids (parts of Crotonoideae), and Euphorbioideae. Potential synapomorphies and biogeographical trends are suggested for these clades. Acalyphoideae s.s., inaperturate crotonoids, and Euphorbioideae tribe Hippomaneae each have two major subclades that represent novel groupings without apparent morphological synapomorphies. Two subfamilies, 14 tribes, and 10 genera were found to be para- or polyphyletic. Noteworthy among these, Omphaleae are embedded in Adenoclineae, Hureae 1 Pachystromateae in Hippomaneae, Ditta in Tetrorchidium, and Sapium s.s. in Stillingia.

Molecular phylogenetic analysis of uniovulate Euphorbiaceae (Euphorbiaceae sensu stricto) using plastid RBCL and TRNL-F DNA sequences

In the present study pollen morphology of the Euphorbeaceae is treated as an additional character in taxonomy. Besides the greater part of the genera occurring in the system of PAX and K. HOFFMANN (1931), most of the genera published after 1931 are studied. The pollen grains have been described with the aid of a terminology as simple as possible. In principle the terminology of IVERSEN and TROELS-SMITH has been followed, although in addition, many improvements of ERDTMAN have been used. One of the simplifications is the rejection of POTONIE’s term sculpture. All elements occurring on the endexine are called structure elements; all structure elements together form the structure of a pollen grain. For the sake of consequence endexine apertures and extexine apertures are discussed separately. Different pollen grains are placed in different pollen types. If the differences are of minor importance, the pollen grains are placed in subtypes. Several types can have some characters in common. To express the correspondences, these types are assembled in configurations. As the pollen types in Phyllanthoideae and Crotonoideae differ distinctly, the division of the Euphorbiaceae in these subfamilies is maintained in the discussion of the results. The Phyllanthodieae can be separated in three large groups of pollen types ( Antidesma configuration, Amanoa configuration and Aristogeitonia configuration), which agrees with the grouping of PAX in 1924. The remaining small configurations belong in taxonomic respect to the genera of the Antidesma configuration. In the Crotonoideae many genera possess pollen grains with a croton-pattern. These genera should be treated as a single group. Besides this natural group, the Plukenetiinae possess pollen grains which are clearly distinguished from other genera in the Crotonoideae. Pollen grains of Omphalea are similar to those in the Plukenetia configuration. This pollen-morphological result agrees with the opinion of CROIZAT. The remaining pollen grains in the Crotonoideae are less easy to differentiate in groups. One of the largest configurations is the Mallotus configuration, which includes most genera of the Acalypheae and several genera or other tribes. The Hippomane configuration is another large one. This configuration comprises the tribes Hippomaneae and Euphorbieae. The pollen grains of both tribes are very similar. The genus Pachystroma is pollen-morphologically as well as taxonomically related to the tribe Hippomaneae. Pera, treated as a separate tribe by PAX and K. HOFFMANN, is related by its pollen grains to some genera in the Acalypheae. Dalechampia is habitually related to the genera in the Plukenetiinae. Pollenmorphological data, however, do not support this relation. The pollen grains of Dalechampia are not similar to any other pollen type. The morphology of the pollen grains of the Stenolobeae is in agreement with the opinion of PAX, that any separation of these Australian genera is an artificial one.

Willem Punt

Papers

Pollen morphology of the Euphorbiaceae with special reference to taxonomy