Jürgen Kellermann

Phylogeny of the tribe Colletieae (Rhamnaceae) – a sensitivity analysis of the plastid region trnL-trnF combined with morphology

Abstract.The phylogenetic relationships within the tribe Colletieae (Rhamnaceae) were examined combining data from a previous morphological analysis with data from the trnL intron and trnL-F spacer. Previous studies have failed to confirm monophyly of the genus Discaria, the only genus of the tribe with an amphiantarctic distribution. The data set was analyzed using direct optimization as implemented in the computer program POY. Direct optimization searches for multiple optimal sequence alignments and is therefore well suited for analyzing DNA sequences including ambiguous alignable regions as found in the present study. Eight different costs were used for treating the indel information. Indels were treated as single events, equal to a fifth character state, or strings of gaps were treated as single events using different costs for opening a gap and extending the gap. The optimal cost set was selected by use of both character-based and topological congruence measures. Both congruence measures agreed upon a single optimal cost set. The resulting tree generally agrees with the current taxonomic treatment of the tribe Colletieae that recognizes six genera out of which three are monotypic. However, monophyly of Discaria was not supported and the results strongly suggest segregating D. nana and D. trinervis, and re-establishing the genus Ochetophila.

Diversification of Ceanothus (Rhamnaceae) in the California Floristic Province

High diversity and endemism in the California Floristic Province (CFP) are an alleged response to the late Cenozoic advent of Mediterranean-type climate in this region. Ceanothus comprises two divergent subgenera with centers of diversity in the CFP. We reconstruct the evolution of Ceanothus by using DNA sequence data from the nuclear gene nitrate reductase. We find that the timing of diversification events is related to geological and climatic history. In both subgenera, diversification is characterized by recent divergence of extant taxa and geographically structured phylogenetic relationships. A strong north-south divergence of subgenus Cerastes across the Transverse Ranges indicates that phylogenetic relationships may be structured by climatically divergent regions of the CFP. Divergence-time estimation suggests that the age of extant diversification in both subgenera is ∼6 Ma. This agrees with the fossil record but predates the hypothesized Quaternary (2-Ma) origin of Mediterranean-type climate in the region.

Phylogenetic analysis and generic limits of the tribe Pomaderreae (Rhamnaceae) using internal transcribed spacer DNA sequences

The tribe Pomaderreae (Rhamnaceae) currently consists of approximately 180 species in seven genera, endemic to Australia and New Zealand. It is the second largest tribe of Rhamnaceae. We undertook a phylogenetic analysis using internal transcribed spacer (ITS) sequence data from 69 representative species of Pomaderreae and five outgroup taxa. The monophyly of Pomaderreae was confirmed. The clades found in the strict consensus tree are mostly consistent with the currently accepted genera of the tribe. All major clades, except Stenanthemum, received moderate to strong bootstrap and jackknife support. Only the relationship between Siegfriedia and Pomaderris received strong support; relationships between other genera did not receive support above 50%. Taxonomic changes are suggested and a preliminary classification of Pomaderreae is proposed, including the monophyletic genera Cryptandra, Pomaderris, Spyridium and Trymalium. Blackallia and Siegfriedia are monotypic. Two new genera are required: one containing two atypical species of Stenanthemum and the second genus consisting of previously unrelated species from three genera that share a 2-carpellate ovary and a characteristic indumentum. The taxonomic status of Stenanthemum requires further examination. A split of Cryplandra into smaller genera is not supported.

Rehabilitation of the South American genus Ochetophila Poepp. ex Endl. (Rhamnaceae: Colletieae)

Abstract Recent molecular and morphological analyses show that Discaria is polyphyletic and consists of two separate clades, Discaria sens. str. and a clade of two species from Chile and Argentina: D. trinervis and D. nana. The genus Ochetophila is here reinstated to accommodate these two species. A revised synonymy is presented, and a new combination is provided for O. nana.

Polianthion, a new genus of Rhamnaceae (Pomaderreae) from Western Australia and Queensland

Recent phylogenetic studies have revealed that four species of Australian Rhamnaceae, tribe Pomaderreae Reissek ex Endl., should be assigned to a new genus. This paper describes Polianthion K.R.Thiele, including one new species, P. collinum Rye, and makes the relevant combinations for P. bilocularis (A.S.George) Kellermann, P. wichurae (Nees ex Reissek) K.R.Thiele and P. minutiflorum (E.M.Ross) K.R.Thiele. The genus is defined by having two carpels, a characteristic dense stellate indumentum on both vegetative and floral parts of the plant, free stipules, long-pedicellate flowers and fruitlets dehiscent for their full length. Three species are found in the south-west of Western Australia and one in eastern Queensland.

Nomenclatural Notes, Typificationsand Name Changes in Trymalium (Rhamnaceae: Pomaderreae)

Abstract The nomenclature and typification of several species of Trymalium Fenzl is reviewed and a revised key to species and infraspecific taxa of the genus is presented. The name T. odoratissimum Lindl. is re-instated for T. floribundum Reissek and the new combination T. odoratissimum subsp. trifidum (Rye) Kellermann, Rye & K.R.Thiele is made. Lectotypes are nominated for T. billardierei Fenzl var. tomentosum Reissek (= T. odoratissimum Lindl. subsp. odoratissimum) and T. urceolare (F.Muell.) Diels. A neotype is designated for T. litorale (Diels) Domin.