I studied evolutionary history in the angiosperm order Apiales, with a special emphasis on interactions between form, time, and space. Four broad categories of problems were addressed: interfamilial relationships in Apiales, the assignment of genera traditionally assigned to the Apiaceae subfamily Hydrocotyloideae, the estimation of divergence times of the major clades, and the reconstruction of the biogeographic history of Apiales. We used molecular markers with different evolutionary properties and rates derived from the plastid (trnD-trnT and rpl16), nuclear (RPB2), and mitochondrial (nad1 intron 2) genomes, from more than 250 species representing all major clades in the order. The nuclear RPB2 region exhibited evidence of at least six duplication events in Apiales and provided a rich source of information for understanding the origins of polyploid lineages, especially in Araliaceae. Sequence comparisons among the copies show that exon regions are highly conserved. All copies appear to be functional but may have undergone subfunctionalization. Phylogenetic analyses of the three genomes suggest that Hydrocotyloideae should be divided into as many as six evolutionary lineages, but that most taxa should be included in subfamilies Azorelloideae and Mackinlayoideae. Relationships among and within the major clades of Azorelloideae need further analyses since many genera appeared non-monophyletic (e.g., Azorella, Schizeilema, and Eremocharis). Mackinlayoideae appeared as the earliest diverging lineage of Apiaceae, but the plastid and nuclear trees were incongruent in the placement of the Platysace clade relative to Mackinlayoideae and the rest of Apiaceae. Among the remaining clades of suborder Apiineae, Myodocapaceae appeared sister to Apiaceae in both plastid and nuclear trees, preceded by the divergence of Araliaceae and then Pittosporaceae. At the base of the gene trees in Apiales, Griseliniaceae and Torricelliaceae formed successive sisters to Apiineae. The placement of Pennantiaceae as sister to the rest of Apiales was confirmed by plastid data, but was not found in the nuclear trees. The order appears to have originated in the Cretaceous, with Apiineae having an age of c. 100 Mya. Australasia appears to be the most likely center of origin for Apiineae and most of its major clades, except Azorelloideae (South America) and Apioideae-Saniculoideae (sub-Saharan Africa).

<p>Vanguerieae is a tribe in the mainly tropical angiosperm family Rubiaceae. The tribe currently comprises around 600 species in 27 genera, with the major part of the species distributed in Africa south of the Sahara. </p><p>The phylogeny of the tribe was investigated using both molecular and morphological data. ITS sequences of the nuclear ribosomal DNA are used in all of the included papers, and in three papers also in combination with sequences from the plastid <i>trnT-F</i> region and/or the <i>rpl16</i> intron. Thirty morphological characters were also investigated and used in combination with molecular data. Several strongly supported groups are found, but eight of the currently recognized genera are also revealed as para- or polyphyletic, i.e., <i>Canthium</i>, <i>Fadogia</i>, <i>Lagynias</i>, <i>Pachystigma</i>, <i>Pyrostria</i>, <i>Rytigynia</i>, <i>Tapiphyllum</i>, and <i>Vangueria</i>. A new classification based on the phylogenetic analyses is suggested and a review of the morphology of Vanguerieae with a focus on taxonomically informative characters is also included. </p><p>The morphologically similar <i>Ancylanthos</i>, <i>Lagynias</i>, <i>Pachystigma</i>, and <i>Tapiphyllum</i> together with a species of <i>Rytigynia</i>, <i>R</i>. <i>fuscosetulosa</i>, are suggested for transfer to <i>Vangueria</i>. All dioecious species of Vanguerieae are found to form a strongly supported group. A study of the group is performed in which all dioecious genera and also twelve undescribed species from Madagascar are included. It is concluded that the whole group should be included in <i>Pyrostria</i>, which necessitates transfers of <i>Canthium</i> subgenus <i>Bullockia</i> and <i>Scyphochlamys</i>. <i>Canthium</i> subgenus <i>Afrocanthium</i> is found to have a position isolated from the type species of the genus and it is suggested that the subgenus is given generic rank as <i>Afrocanthium</i>. A comparison of nuclear and chloroplast phylogenies shows that several species in a subgroup of the tribe have incongruent positions, and possible explanations for the incongruencies are discussed. </p>

Vanguerieae is a tribe in the mainly tropical angiosperm family Rubiaceae. The tribe currently comprises around 600 species in 27 genera, with the major part of the species distributed in Africa south of the Sahara. The phylogeny of the tribe was investigated using both molecular and morphological data. ITS sequences of the nuclear ribosomal DNA are used in all of the included papers, and in three papers also in combination with sequences from the plastid trnT-F region and/or the rpl16 intron. Thirty morphological characters were also investigated and used in combination with molecular data. Several strongly supported groups are found, but eight of the currently recognized genera are also revealed as para- or polyphyletic, i.e., Canthium, Fadogia, Lagynias, Pachystigma, Pyrostria, Rytigynia, Tapiphyllum, and Vangueria. A new classification based on the phylogenetic analyses is suggested and a review of the morphology of Vanguerieae with a focus on taxonomically informative characters is also included. The morphologically similar Ancylanthos, Lagynias, Pachystigma, and Tapiphyllum together with a species of Rytigynia, R. fuscosetulosa, are suggested for transfer to Vangueria. All dioecious species of Vanguerieae are found to form a strongly supported group. A study of the group is performed in which all dioecious genera and also twelve undescribed species from Madagascar are included. It is concluded that the whole group should be included in Pyrostria, which necessitates transfers of Canthium subgenus Bullockia and Scyphochlamys. Canthium subgenus Afrocanthium is found to have a position isolated from the type species of the genus and it is suggested that the subgenus is given generic rank as Afrocanthium. A comparison of nuclear and chloroplast phylogenies shows that several species in a subgroup of the tribe have incongruent positions, and possible explanations for the incongruencies are discussed.

The Malacothamnus alliance consists of three genera, Iliamna, Malacothamnus, and Phymosia. The genera are considered taxonomically complex since hybridization freely occurs, polyploidy levels vary, and there is a lack of distinct morphological characters to delineate taxa. Several taxonomic treatments have been prepared for each genus, but relationships within the genera and the relationship of the Malacothamnus alliance to others in the Malvaceae remains unknown. This multifaceted study aimed to (a) examine the monophyly of the Malacothamnus alliance and its position in the Malvaceae, (b) determine the relationships between genera in the alliance, (c) compare variation of nuclear and chloroplast genes in the alliance, (d) prepare revised taxonomic treatments for Iliamna and Malacothamnus, and (e) examine the probability of successful hybridization in Iliamna. The monophyly of the Malacothamnus alliance was not confirmed using DNA sequences of both nuclear and chloroplast regions. In Iliamna, little sequence variation was detected among taxa in the Rocky Mountains; however, the nuclear and chloroplast regions conflicted with regard to the relationships of the western and eastern taxa. An ancestral copy of the chloroplast genome is shared between the two eastern U.S. Iliamna species and Phymosia (Bahamas and Mexico). The nuclear ITS sequences indicated the western U.S. Iliamna species were more closely related to Phymosia and Malacothamnus than to other species in Iliamna. Neither data set provided sufficient variation to resolve relationships of species in Malacothamnus. Genetic variation and the feasibility of hybridization in Iliamna supported the results of the broader phylogenetic studies. Iliamna corei and I. remota are recently derived from I. rivularis. Hybrid offspring of I. corei and I. remota had higher viability and fecundity than did hybrids between crosses of either species and I. rivularis. The Virginia populations of I. corei and I. remota are more genetically similar than either is to Illinois populations of I. remota. However, the species are morphologically distinct and can easily be distinguished from others in the genus. Revised taxonomic treatments for Iliamna and Malacothamnus based on surveys of herbarium material are presented. Taxonomic revisions include the new combinations of Iliamna grandiflora subsp. grandiflora and I. grandiflora supsp. crandallii and the resurrection of Malacothamnus hallii and M. orbiculatus. / Ph. D.

No description available.