Thesis (Ph. M.)--University of Wisconsin--Madison, 1943. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--Ohio State University. / Bibliography: leaves 28-29.

Photocopy of typescript. / Digitized by Kansas Correctional Industries

Homeosis, the expression of features characteristic of one structure in the position of a different structure, and its role in floral development and evolution is explored in several different species of angiosperms. The expression of perianth features in stamen positions, and of inflorescence features within the flower is demonstrated in a comparative study of single- and double-flowering begonias. Floral development in three native plant species is then described, and compared to published accounts of development and phylogeny in related species to show: the expression of petal features in stamen positions in Sanguinaria canadensis; the replacement of petals with stamens and vice versa within and among plants of Actaea rubra; and the replacement of stamens with tepals in Calla palustris. These three species are all examples of naturally occurring homeosis, suggesting an important role for homeosis as an evolutionary process.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1942. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 23-24).

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Orientador: Marlies Sazima / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-15T04:48:07Z (GMT). No. of bitstreams: 1 Wyatt_GrahamEdward_M.pdf: 9293107 bytes, checksum: b33c1975f0e55d35f2d12ecf77d49b40 (MD5) Previous issue date: 2009 / Resumo: Neste estudo, são apresentadas informações sobre a biologia floral, polinização e reprodução de 13 espécies monóicas de Begônia (Begoniaceae) ocorrentes no Parque Estadual da Serra do Mar, São Paulo. A fenologia da reprodução destas espécies é anual e as flores apresentam tépalas brancas com algumas variações, odor leve e agradável, não há néctar sendo pólen o único recurso, os elementos reprodutivos são de cor amarela, sendo os estigmas amplos e os estames numerosos. A antese é diurna e a duração das flores é longa (seis a 15 dias). A presença de numerosas semelhanças morfológicas entre flores estaminadas e pistiladas das espécies apóia a hipótese de mimetizmo intersexual. Não ocorre apomixia, as autopolinizações em B. integerrima e B. itatinensis não desenvolveram frutos e sementes, mas a formação de frutos em condições naturais é alta para várias espécies (77 - 88%). Não houve o desenvolvimento de tubos polínicos em flores autopolinizadas de B. integerrima, indicando a possível ocorrência de autoincompatibilidade esporofitica. A presença de grande quantidade de tubos polínicos atingindo os óvulos em flores de condições naturais indica que as flores receberam altas cargas de pólen. Os polinizadores principais foram abelhas de pequeno porte pertencentes a diversas tribos de duas famílias. Dez espécies de abelhas foram registradas em oito espécies de Begônia e o modo de obtenção de recursos é por vibração, com exceção de Trigona spinipes. As visitas às flores estaminadas foram mais freqüentes que às para flores pistiladas, cujas visitas são por engano, uma vez que não oferecem recurso. Assim também, a duração das visitas às flores pistiladas foi significativamente mais curta do que a duração em flores estaminadas (P < 0.001). Concluímos que visitas às flores pistiladas, embora sejam relativamente menos freqüentes do que as para flores estaminadas, ocorrem por engano e com freqüência suficiente para o sucesso reprodutivo destas espécies / Abstract: The reproductive biology of 13 monoecious species of Begonia (Begoniaceae) that occur in the Serra do Mar State Park, São Paulo, Brazil, was investigated. The reproductive phenology of these species is annual and present flowers with white tepals with some variations, light and agreeable odor, present pollen as a reward, lack nectar, yellow reproductive elements, ample style/stigma and numerous stamens. Anthesis is diurnal and floral duration is long (6 - 15 days). The presence of numerous morphological similarities between staminate and pistillate flowers of these species supports the intersexual mimicry hypothesis. Of 11 species tested, none proved to be apomictic, despite high levels of fruit-set (77 - 88%) under natural conditions. Self-pollinations of B. integerrima and B. itatinensis produced no fruits or seeds, and the complete absence of pollen tubes in self-pollinated flowers of B. integerrima suggests that the species is genetically self-incompatible. Flowers pollinated under natural conditions showed many pollen tubes that reached ovules, suggesting that adequate numbers of compatible pollen grains were transported by pollinators. The principal pollinators were small bees of the Apidae and Halictidae. Ten species of bees were observed to visit eight species of Begonia, and pollen collection occurred by means of vibration, except for Trigona spinipes. Visits to rewarding staminate flowers were significantly more frequent than visits to unrewarding pistillate flowers. Duration of visits to pistillate flowers also were significantly shorter than the duration of visits to staminate flowers. We conclude that mistake visits to pistillate flowers, though relatively less frequent than visits to staminate flowers, occur by mistake but with sufficient frequency to allow for successful reproduction in natural populations of these species / Mestrado / Mestre em Biologia Vegetal