73 research outputs found
Pollen structure, tetrad cohesion and pollen-connecting threads in Pseuduvaria (Annonaceae)
No full textThe structure of the pollen of 42 species of Pseuduvaria (Annonaceae) is described. The pollen is consistently inaperturate, isopolar and radially symmetrical. Four basic patterns of exine sculpturing are identified: rugulate, verrucate, scabrate and psilate. The exine stratification of one representative species, P. macrocarpa, is shown to be entirely ectexinal. The ectexine consists of a discontinuous outer tectal layer, a columellar infratectal layer, and an inner lamellar foliated foot layer; the intine is very thin and fibrillar. The pollen is invariably released as acalymmate tetrads, in which the tectum is absent from the proximal walls. The individual pollen grains within the tetrads are connected by crosswall cohesion, involving both exine and intine; this form of cohesion has not hitherto been reported in the Annonaceae. In addition, pollen grains of neighbouring tetrads are connected in two different ways, viz. short exine connections and non-sporopollenin pollen-connecting threads. Neither of these cohesion mechanisms has previously been reported for the genus. The function of the various forms of cohesion between pollen grains and tetrads in Pseuduvaria is discussed as a mechanism to enhance the efficiency of pollination by enabling the fertilization of multiple ovules following a single pollinator visit. © 2003 The Linnean Society of London.link_to_subscribed_fulltex
A Late Miocene origin of the basal angiosperm genus Pseuduvaria (Annonaceae) in Sundaland, with subsequent diversification in New Guinea
No full textA late Miocene origin of the basal angiosperm genus Pseuduvaria (Annonaceae) in Sundaland, with subsequent dispersal in New Guinea
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(1519-1520) Proposals to reject the names Meiogyne macrocarpa and Mitrephora trimera (Annonaceae)
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Phylogenetic relationships of Dasymaschalon, Desmos and related genera (Annonaceae) based on molecular data
No full textEvolutionary loss of inner petals in Dasymaschalon (Annonaceae): morphological character evolution and implications for generic delimitation
No full textThe 8th Flora Malesiana Symposium, Singapore, 23-27 August 2010
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