Algal collections from eight lakes in southwestern British
Columbia have been examined. The desmid flora consists of 205 species and 44 varieties in 26 genera. Two genera, Spino-closterium and Spinocosmarium, and several species of other genera, are reported for the first time from British Columbia. Seasonal changes in the abundance and kinds of desmids occurring in collections
are noted.
Cultural studies on the variability of Triploceras gracile and T. verticillaturn were undertaken to determine the validity
of subspecific characters used in the genus. These studies showed that the apical radiation of the semicell (the number of lobes at the end of the semicell) can vary from biradiate (2-lobed) to quadriradiate (4-lobed) within a single clone. Thus in the genus this character must be discarded as a taxonomic criterion.
The morphology of the protuberances of the semicells was constant
in both species, and is a useful subspecific character. A number of abnormal forms occurred in cultures but were not observed in field collections.
The nuclear cytology of Triploceras was investigated. T. verticillaturn has the largest chromosomes yet reported for the Desmidiaceae, almost 20 u in length measured at late prophase in colchicine treated cells. The chromosome number for this species is n = 15-20. The chromosomes of T. gracile are smaller, but no chromosome counts were obtained for this species. / Science, Faculty of / Botany, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/38202 |
| Date | January 1965 |
| Creators | Gerrath, Joseph Frederick |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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