Showing papers by "Michael F. Fay published in 2003"

A revised generic synopsis of hyacinthaceae in sub-saharan africa, based on molecular evidence, including new combinations and the new tribe pseudoprospereae

Abstract: A revised generic synopsis of sub-Saharan Hyacinthaceae is presented, based on a molecular phylogenetic analysis of the family. Generic rank is accorded only to reciprocally monophyletic clades that can be distinguished by recognizable morphological discontinuities, thereby permitting an appropriate generic assignment of species not included in the analysis. Three subfamilies are recognized within the region. Subfamily Ornithogaloideae, characterized by flattened or angular seeds with tightly adhering testa, is considered to include the single genus Ornithogalum, which is expanded to include the genera Albuca, Dipcadi, Galtonia, Neopatersonia and Pseudogaltonia. Recognizing any of these segregates at generic level renders the genus Ornithogalum polyphyletic, while subdivision of Ornithogalum into smaller, morphologically distinguishable segregates in order to preserve the monophyly of each is not possible. Subfamily Urgineoideae, characterized by flattened or winged seeds with brittle, loosely adhering testa, comprises the two mainland African genera Bowiea and Drimia. The latter is well circumscribed by its deciduous, short-lived perianth and includes the previously recognized genera Litanthus, Rhadamanthus, Schizobasis and Tenicroa. The monotypic Madagascan Igidia is provisionally included in the subfamily as a third genus on the basis of its seeds, pending molecular confirmation of its relationships. Subfamily Hyacinthoideae resolves into three clades, distinguished as tribes Hyacintheae (strictly northern hemisphere and not treated further), Massonieae and Pseudoprospereae tribus nov. Full descriptions and a key to their identification are provided for all genera. New combinations reflecting the generic circumscriptions adopted here are made for most African and all Indian and Madagascan species.

Temperature-based population segregation in birch

Abstract: Mean temperature of establishment years for warm- and cold-year subpopulations of a naturally occurring stand of Betula pendula (birch) shows a difference equivalent to that between current temperatures and temperatures projected for 35-55 years hence, given 'business as usual.' The existence of 'pre-adapted' individuals in standing tree populations would reduce temperature-based advantages for invading species and, if general, bring into question assumptions currently used in models of global climate change. Our results demonstrate a methodology useful for investigating the important ecological issue of adaptation vs. range shifts as a means of response to climate change.

Species delimitation and the origin of populations in island representatives of Phylica (Rhamnaceae).

Abstract: Relationships between the closely related island species of Phylica (Rhamnaceae) and a mainland species, P. paniculata, were elucidated using amplified fragment length polymorphisms (AFLPs). Parsimony, neighbor joining, and principal coordinate (PCO) analyses indicated that each of the species studied is distinct. AFLPs were also useful in elucidating the genetic relationships and possible infraspecific origins of different island populations in the Atlantic and Indian Oceans. Phylica nitida on Reunion is likely to have been derived from P. nitida on Mauritius. Although the sampling on New Amsterdam is not extensive, the data are also consistent with the hypothesis that P. arborea on New Amsterdam was derived from a single colonization of P. arborea from Gough Island. Similarly, the Gough Island population appears to have been derived from a single colonization event, but it is so distinct from those on Tristan da Cunha, that there may have been two separate dispersals to Gough and Tristan/Nightingale from different lines of the mainland progenitor. There is also evidence of a recolonization from Gough to Tristan da Cunha. Thus, Phylica arborea is capable of repeated long distance dispersal, up to 8000 km, even though the fruits and seeds are not of a type normally associated with this phenomenon.

Genetics of colonization in Hypochaeris tenuifolia (Asteraceae, Lactuceae) on Volcán Lonquimay, Chile.

Abstract: Understanding the genetics of colonizing populations has been, and continues to remain, an important focus in evolutionary biology. Different theoretical models predict varying levels of genetic variation in colonizing populations depending upon strength of founder effect, gene flow and rate of population growth and immigration following colonization. We analyse overall genetic variation using amplified fragment length polymorphism markers in colonizing populations of Hypochaeris tenuifolia (Asteraceae) in the southern Andes. Volcan Lonquimay newly erupted on 25 December 1988, producing a side cone, La Navidad, and sent lava and ash into surrounding areas. Many domesticated animals (estimated at 10 000) and many natural plant populations were destroyed. Into this new open habitat have come immigrant populations of several angiosperm species, most conspicuously H. tenuifolia that forms leaf rosettes with flowering scapes to 15 cm and orange-yellow heads 1-2 cm in diameter. Genetic diversity in five founder populations in the eruption zone is compared with that from five nearby survivor populations, as well as with eight isolated northern and four southern populations from throughout the entire range of the species in Chile. Results from 477 individuals representing 447 different multilocus phenotypes, yielded 170 DNA fragments of which 144 (85%) were polymorphic. Genetic diversity within founder populations is neither lower than in survivor populations nor in isolated populations throughout the range of the species, but it is lower among founder populations than among other populations immediately and distantly outside the zone of disturbance. Closest genetic similarity occurs between founders and nearby survivor populations as well as those in adjacent southern regions.

Hybridisation between Schoenoplectus tabernaemontani and S. triqueter (Cyperaceae) in the British Isles

Abstract: Schoenoplectus samples from the Rivers Arun, Medway, Tamar and Thames were studied using AFLP genetic fingerprinting to test hypotheses concerning the origin of hybrids of S. triqueter with S. lacustris and S. tabernaemontani. Schoenoplectus lacustris and S. tabernaemontani were shown to be only distantly related, and therefore it is appropriate that they be treated as two distinct species rather than as two subspecies of S. lacustris, as recommended by some authorities. S. lacustris was excluded as a possible parent in all potential hybrids studied from all rivers, and evidence of additivity was found between the fingerprints of S. tabernaemontani and S. triqueter in all cases. Material collected as pure species turned out to be of hybrid origin in two cases, and identification of the hybrids and S. tabernaemontani appears to be difficult as a result of phenotypic plasticity. Conservation implications of the results and areas of possible future work are discussed.

Plate 461. Cosmos Atrosanguineus Compositae

Abstract: The taxonomic history, cultivation requirements, and restricted natural distribution of Cosmos atrosanguineus are discussed. A full synonymy, description, colour plate, and line drawings of the dissections of this species are given. This species is a plant in peril, believed to be extinct in the wild.