Browsing by Author "Schrire, Brian David."

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Systematic studies in African Indigofereae (Leguminosae, Papilionoideae)
(1991) Schrire, Brian David.
A cladistic analysis of 51 generic and infrageneric taxa in the tribe Indiqofereae (Papilionoideae) is presented, comprising q 570 species in Africa and Madagascar. Traditionally, 4 genera have been recognized: Phylloxylon (q 5 species), Rhynchotropis (2 species), Cyamopsis (q 4 species) and Indigofera (510-520 species in Africa). 3 genera have been reinstated, i.e. Vaughania (11 species), Indigastrum (11 species) and Microcharis (q 26 species). Vaughania was previously considered to be a monotypic genus (later placed in synonomy under Indigofera); the others have recently been treated as subgenera of Indigofera. A new subgenus is described in Indigostrum. (subgenus Argyraeae Schrire) as well as 17 new sections and one subsection in Indigofera. 18 infrageneric taxa in Indigofera are specified at a new rank. Taxonomic affinities with neighbouring tribes are discussed. A historical review is given of infrageneric subdivision. in Indigofera along with a newly proposed classification of infrageneric taxa in Africa. The cladogram is used to study character evolution in the tribe; from a) an ecological perspective (by identifying aptations) and b) a phylogenetic perspective (by identifying constraining interactions between morphologies). Aptations and critical morphologies are mapped on the cladogram to interpret developmental constraints, and the order and direction of character transformations. Key morphologies are a class of developmental constraints defined here for the first time. The cladogram and character analyses are used to interpret a phylogenetic tree of the tribe in Africa. Major phase. in the evolution of Indigofereae are hypothesized on the basis of developmental constraints, phytogeography and ecology. A taxonomic revision above the species level in Africa is presented, including keys and descriptions of genera and infrageneric taxa in Indigofera. Species of Indigofereae occurring in tropical Africa are listed, while a synopsis is given of southern African species with literature citations, synonymy and typification. 29 new combinations are made in Microcharis and Indigastrum.
A taxonomic revision of the tribe Desmodieae (Leguminosae - Papilionoideae)
(1984) Schrire, Brian David.; Hennessy, Esme F.
The tribe Desmodieae has a pantropical distribution and is one of the most advanced tribes in the subfamily Papilionoideae. Despite this fact, the tribe was already present in the fossil record of the early Tertiary and so the Papilionoideae appear to be much older than is currently accepted. With its greatest centres of development in tropical Asia and America, Africa is relatively poorly endowed and only four genera comprising sixteen species occur in the Flora of southern Africa. Many of these species are widespread in the old World tropics and the few African endemics appear to be closely related to them. Desmodium is the largest genus with the bulk of species belonging to the Asian subgenus Sagotia. Of the two sections of Sagotia represented in Africa, section Nicolsonia is clearly more derived than section Heteroloma, showing many characters intermediate between Heteroloma and the considerably more derived genera Alysicarpus and Lespedeza. Other Desmodium species either of the Old or New World have often become naturalised as weeds in Africa. Pseudarthria is a genus derived by an aneuploid increase of the basic x = 11 for the tribe rather than an aneuploid decrease as in the case of Alysicarpus and Lespedeza. A re-count of the chromosome number of P. hookeri (2n = 26) matches the count obtained in another species of Pseudarthria for the first time. Flowering strategy and flower structure in the tribe are the result of intense coevolution with the ecological requirements of skilled bee pollinators and although many bees can trip Desmodieae flowers, only a relatively few high energy demanding, traplining bees are able to bring about effective pollination. The overall breeding system represents a fine balance between the need for selfing and the need for outcrossing in order to produce enough seed of sufficient quality to survive in unstable environments.