Studies in theCompositaeof the Arabian Peninsula and Socotra — 7.Erythroseris, a new genus and the previously unknown sister group ofCichorium (CichorieaesubtribeCichoriinae)

Phylogenetic relationships for Hieracium subgen. Pilosella were inferred from chloroplast (trnT-trnL, matK) and nuclear (ITS) sequence data. Chloroplast markers revealed the existence of two divergent haplotype groups within the subgenus that did not correspond to presumed relationships. Furthermore, chloroplast haplotypes of the genera Hispidella and Andryala nested each within one of these groups. In contrast, ITS data were generally in accord with morphology and other evidence and were therefore assumed to reflect the true phylogeny. They revealed a sister relationship between Pilosella and Hispidella and a joint clade of Hieracium subgenera Hieracium and Chionoracium (Stenotheca) while genus Andryala represented a third major lineage of the final ingroup cluster. Detailed analysis of trnT-trnL character state evolution along the ITS tree suggested two intergeneric hybridization events between ancestral lineages that resulted in cytoplasmic transfer (from Hieracium/Chionoracium to Pilosella, and from the introgressed Pilosella lineage to Andryala). These chloroplast capture events, the first of which involved a now extinct haplotype, are the most likely explanation for the observed incongruencies between plastid and nuclear DNA markers.

Many species of the paleotropical pioneer tree genus Macaranga Thou. (Euphorbiaceae) live in association with ants. Various types of mutualistic interactions exist, ranging from the attraction of unspecific ant visitors to obligate myrmecophytism. In the latter, nesting space and food bodies are exchanged for protection by highly specific ant partners (mainly species of the myrmicine genus Crematogaster). As a first step toward elucidating the coevolution of ant-plant interactions in the Macaranga-Crematogaster system, we have initiated a molecular investigation of the plant partners' phylogeny. Nuclear ribosomal DNA internal transcribed spacer (ITS) sequences were analyzed for 73 accessions from 47 Macaranga species, representing 17 sections or informally described species groups. Three accessions from the putative sister taxon Mallotus Lour, were included as outgroups. Cladograms of the ITS data revealed Macaranga to be nested within Mallotus. ITS sequences are highly similar within section Pachystemon s.str., suggesting a relatively recent and rapid radiation of obligate myrmecophytes within this section. Forty-three accessions, mainly of ant-inhabited species, were additionally investigated by random amplified polymorphic DNA (RAPD) and microsatellite-primed PCR (MP-PCR) techniques. Phenetic analysis of RAPD and MP-PCR banding profiles generally confirmed the ITS results. Best resolutions for individual clades were obtained when ITS and RAPD/MP-PCR data were combined into a single matrix and analyzed phenetically. The combined analysis suggests multiple (four) rather than a single evolutionary origin of myrmecophytism, at least one reversal from obligate myrmecophytism to nonmyrmecophytism, and one loss of mutualistic specifity. Copyright 2001 Academic Press.