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dc.contributor.advisorCox, Elenor R.
dc.creatorWahrer, Richard James
dc.descriptionTypescript (photocopy).en
dc.description.abstractThe valve morphology of twenty four taxa of the genus Eunotia from Texas and Alaska was examined with the light and scanning electron microscopes with particular emphasis on the terminal nodules, raphe, hyaline areas, striae patterns and labiate process. The labiate process is a good diagnostic character because this structure is found in all the species examined (except E. triodon) and its location is consistent within a species. Taxonomic groupings based on the location of the labiate process, striate patterns, raphe placement and the presence of spines are proposed. Evolutionary trends of each morphological character are outlined. The evolution of Eunotia at the varietal rank seems to exemplify phyletic gradualism; however, evolution between species and closely related genera seems to exemplify punctuated equilibria. Species discussed include: E. arcus, E. bidentula, E. diodon, E. elegans, E. exigua, E. flexuosa, E. flexuosa var. eurycephala, E. formica, E. hexaglyphis, E. lunaris, E. lunaris var. subarcuata, E. monodon var. constricta, E. naegeli, E. parallela, E. pectinalis var. undulata, E. pectinalis var. ventricosa, E. praerupta var. bidens, E. quaternaria, E. serra var. diadema, E. sudetica, E. triodon, E. valida, E. vanheurckii and E. zygodon.en
dc.format.extentxi, 173 leavesen
dc.rightsThis thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use.en
dc.subject.classification1981 Dissertation W137
dc.subject.lcshScanning electron microscopesen
dc.titleComparative valve morphology of selected species of Eunotia Ehr. (Bacillariophyceae)en
dc.typeThesisen A&M Universityen of Philosophyen D. in Philosophyen
dc.contributor.committeeMemberBryant, Vaughn
dc.contributor.committeeMemberClark, W. J.
dc.contributor.committeeMemberThurston, E. L
dc.format.digitalOriginreformatted digitalen
dc.publisher.digitalTexas A&M University. Libraries

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