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

Field and culture studies have been carried out with the epiphytic red alga, Ceramium codicola J. Agardh, with the objective of determining what factors in its biology cause it to be limited to growth on one host plant, Codium fragile (Suringar) Hariot. A survey of epiphytes of C. fragile and C. setcheIIii confirm the absence of C. codicoIa on C. setcheIIii and shows that C. codicola is the most abundant epiphyte on C. fragiIe. More species of epiphytes were present in wave sheltered areas. C. codicoIa was not present in samples from the Strait of Georgia. In culture, C. codicoIa grew to reproductive maturity apart from C. fragiIe from spores, but the life history was not completed. The presence of living or extracted C. fragiIe or C. setcheIIii did not promote germination, growth or reproduction of C. codicola, and typically inhibited it. C. codicoIa did not grow well at temperatures above 15°C in culture; C. fragiIe, Ceramium pacificum and C. gardner i grew weII at 10-18°C. Rhizoids of C. codicola have bulbous tips, which appears to be genetically determined. Substratum can affect later development of these rhizoids, which may obscure the bulbous nature of the rhizoid tips. C. codicoIa is unable to produce digitate holdfasts on its rhizoid tips, as was observed in other Ceramium spp. , and may only be able to attach by entangling its rhizoids in loosely constructed substrata such as Codium spp. C. setcheIIii is not suitable because it is too compact, and penetration of rhizoids is inhibited. Field studies show that C. codicoIa is reproductive throughout the year, although reduced in the winter. Thallus length was also reduced in the winter. In addition, thalIi were longer in wave sheltered sites, and longer in the upper regions of their intertidal distribution. Male and female gametophytes and tetrasporophytes of C. codicola exhibit a hetermorphism in branching pattern. Gametophytes differ from tetrasporophytes by having more primary branches and larger angles of branching. Females differ from males by having a higher degree of proliferous branching, resulting in a higher number of primary branches and a higher branching ratio. Branching pattern in females may be the result of continued growth of involucral ramuli, and it may optimize reproductive potential. / Science, Faculty of / Botany, Department of / Graduate

Developmental studies were made on certain intertidal algal communities at three sites on Juan de Fuca Strait, B.C. The object was to describe the form and structure of these communities and to provide an interpretation that would account for the manner in which they occur. Periodic observations were made on communities developing on denuded rock surfaces and on in situ communities. By using the denuded-quadrat method, a method familiar to terrestrial plant ecologists, species-distribution indices of frequency and abundance were taken to quantitatively describe the stages of recolonization. Data relative to the developmental process, such as life span and period of reproduction of the species involved, were also gathered. The experimental data reveal a pattern of development that is consistent and predictable. Despite the presence of an orderly sequence of events, there is no evidence to indicate that this is an expression of ecological succession. The partial or even total elimination of a population is concluded not to be due to any changes in habitat originated by that population. Instead its elimination, partial or otherwise, is considered to be a consequence of the degree of establishment of the proceeding population. The successional phenomenon, which can be altered by seasonal populants, is related to the morphological nature of the colonizing species. Unicellular forms appear before filamentous ones, and filamentous forms appear before parenchymatous ones. Such a succession is interpreted as being indicative of the relative growth rates and life spans of the growth forms. The length of time in which a population occupies an area is determined by these factors. The presence or absence of growth space can he a main cause for local distributional patterns, especially for ephemeral species. The dynamic structure of the communities studied is attributed to species interaction involving three interrelated factors: (1) the morphology of the organisms; (2) the phenological nature of germination, growth, reproduction, and of spore or gamete release; and (3) the competition for space. / Science, Faculty of / Botany, Department of / Graduate

Data on 75 species from 124 quadrats collected from the intertidal and subtidal regions in the Flat Top Islands area of Georgia Strait in late spring to early autumn, 1972, were subjected to a number of community analysis techniques including a Williams and Lambert association analysis, a species constellation diagram, a cluster analysis of quadrats, an inverse analysis of species, a Zurich-Montpellier analysis, and a Bray and Curtis ordination. Association analysis and cluster analysis classification of quadrats delimited four communities: an intertidal, an upper subtidal, a lower subtidal, and a sandy bottom community. Species constellation diagram and inverse analysis classification of species delimited six communities: an intertidal, a shallow red algal, a laminarian, a turf, a deep water, and a sandy-bottom community. The Zurich-Montpellier analysis and the Bray and Curtis ordination did not produce clearly definable groups of quadrats. The results of all the analyses indicate that marine benthic algae form broadly overlapping distributions from which communities of varying affinities can be extracted. / Science, Faculty of / Botany, Department of / Graduate

A comparative, year long (15 month) study of three lakes (Whonock, Munday, Como) in the Lower Fraser Valley, British Columbia was undertaken to gain information on the physicochemical and seasonal limits of scale-bearing Synuraceae (Chrysophyta). In addition, sporadic collections were made in different lakes in this region to augment the information provided from the three main lakes. The synuracean taxa are reviewed with worldwide distribution lists, and environmental and seasonal information are discussed. Thirty-one taxa of Chrysophyceae were identified, of which 20 are in the Synuraceae. Eight taxa within this family are new records for British Columbia, viz. : Mallomonas cratis var. asmundiae Wujek et Van der Veer Mallomonas papillosa Harris et Bradley Mallomonas doignonii var. tenuicostis Asmund et Cronberg Mallomonas transsylvanica Peterfi et Momeu Mallomonopsis ouradion (Harris et Bradley) Harris Paraphysomonas vestita (Stokes) de Saedeleer Synura splendida Korshikov Synura glabra Korshikov It was found that the Synuraceae are not restricted to cold waters, as often assumed. Some taxa are present throughout the year. They do seem to favour acidic and sometimes dystrophic environments, and it is suggested that factors such as pH or water chemistry should be investigated as probable controlling factors for synuracean populations. Of the 11 non-synuracean Chrysophyceae noted', six are new records for the Province: Bicoeca kepneri, Chrysococcystis elegans, Dinobryon crenulatum, Epipyxis lauterbornii, Epipyxis utriculus var. acuta, and Eusphaerella turfosa. / Science, Faculty of / Botany, Department of / Graduate

A preliminary electrophoretic study on Bangia vermicularis Harvey (Rhodophyta) along the coast of British Columbia was undertaken to determine whether enzyme banding patterns could be used to identify the relatedness of the populations which varied in chromosome number (3, 6 or 4) and life history (asexual or sexual). Material from nineteen sites was tested for seven enzymes: glutamate dehydrogenase (GDH); malate dehydrogenase (MDH); lactate dehydrogenase (LDH); superoxide dismutase (SOD), glucose 6-phosphate dehydrogenase (G6PDH); phosphoglucoisomerase (PGI); and phosphoglucomutase (PGM). Unlike higher plants, some of the banding patterns obtained in Bangia could only be explained if the enzymes SOD, GDH, LDH and PGI are monomers and the enzymes PGM, SOD, GDH, PGI, and G6PDH have only one cellular location. Generally, with the exception of two enzymes, PGI and G6PDH, which were highly polymorphic, only one to three bands were evident. Considerable amounts of variation in the mobility of the isoenzymes were detected between populations independent of chromosome number or sexuality. Contrary to expectations, often populations with three chromosomes or six ' chromosomes had the same number of loci and many of the three chromosome populations had some banding patterns indicative of diploids. Consequently, if there had been a polyploid origin of the six chromosome populations then there must also have been many gene duplications in the three chromosome populations. Alternatively, if the three chromosome populations arose by aneuploid reduction within a six chromosome population then there must also have been gene silencing and/or the formation of null alleles. Populations that were very close geographically differed to a large extent suggesting that there may be little gene flow between populations. The variability between populations could be explained by isolation over long periods of time during which changes could have occurred in the structure and regulation of the enzymes tested. / Science, Faculty of / Botany, Department of / Graduate

The autecology of the estuarine alga, Blidingia minima var. subsalsa (Kjellman) Scagel (Chlorophyceae) was considered with regard to its growth, reproduction and distribution. Studies were conducted on the Squamish River estuary, British Columbia, from May 1974 to July 1975 and in the laboratory from January to August 1975. The major environmental factors considered were light, temperature, salinity, nutrients and desiccation. The alga occurred on the Squamish River delta in the upper intertidal zone. Biomass, as estimated by percent cover, increased in the period March to early May, then remained stable or decreased during spring runoff in May and June, finally increasing to a maximum in August. Increases in percent cover were associated with brackish salinity, high light intensity, high air temperature, considerable desiccation, an absence of algal competitors and possibly favourable ion ratios. The three factors investigated in the laboratory (temperature, salinity and nutrients) interacted in their effect on net photosynthesis. Reproduction in the laboratory occurred by release of quadri-flagellate and isomorphic biflagellate swarmers. Some biflagellate swarmers fused and germinated, producing isomorphic plants. The period of swarmer release was from January to early May. The alga was perennial but during the winter only its prostrate basal disc was present. Maximum vertical distribution was from 1.5 to 4.0 m above chart datum (lowest low water). Maximum percent cover occurred at ca. 3.25 m. The upper limit appeared to be associated with unfavourable osmotic conditions, e.g. rain or desiccation, and the lower limit with low light intensities. Horizontal distribution was limited by absence of salt water on the freshwater side and competition from Fucus distichus subsp. edentatus (De la Pylaie) Powell on the marine side of the estuary. Blidingia minima var. subsalsa1s geographical and habitat distribution was also examined by reference to literature reports and herbarium collections. The species is cosmopolitan, occurring in every ocean except the Indian and Antarctic with most reports from polar and temperate regions. The variety occurs in brackish, marine and freshwater habitats. / Science, Faculty of / Botany, Department of / Graduate

The purpose of the study was to examine the distributional patterns of diatoms in the surface sediments of ten southern British Columbia inlets with respect to oceanographic and hydrographic setting, and phytoplankton distribution and productivity. The study area was divided on the basis of inlet type (high, medium, and low runoff), within-inlet gradients, and zones (northern, central, and southern). A small group of species dominated the 95 sediment assemblages. There was a fairly good correlation between the biocoenoses and the thanatocoenoses in the sense that most of those species reported as dominants in the phytoplankton were also dominants in the sediment assemblages. However, there were discrepancies and these could not be explained on the basis of the relative silicification of the diatom valves. Skeletonema costatum, usually considered a weakly-silicified, dissolution-sensitive species, was abundant in British Columbia sediments. Both the pacifica and the aestivalis forms of Thalassiosira aestivalis were abundant in the phytoplankton, but only the pacifica form was preserved well in the sediments. Thalassiosira nordenskioeldii, which is found in other sediment assemblages, was rare in most British Columbia sediments. The distributional patterns of freshwater and marine littoral species appeared to be indicative of river sources entering the estuarine system. The absolute abundance of diatoms in the sediment assemblages increased from the northern to the southern zone. Within the inlets, both absolute abundance and primary productivity increased toward the mouth. Estuarine circulation did not appear to alter substantially the spatial relationship between the biocoenoses and the thanatocoenoses. In general, individual species and species-groups often exhibited distinct distributional patterns which could be related to inlet type, zonal, and within-inlet patterns. In particular, the principal coordinate analysis showed a zonal correlation between the dominant species in the sediment assemblages, and primary productivity, salinity, and temperature in the surface waters. / Science, Faculty of / Botany, Department of / Graduate

Patterns in algal community structure and physiochemical characteristics of streams and one impounded subalpine lake in the mountainous North Alouette River watershed, British Columbia, were described for one year from June 1977 to June 1978. In this period, 266 algal taxa were recognized, of which 59 were previously unrecorded in the province. The streams were characterized by an epilithic flora consisting predominantly of. unbranched Chlorophyta and secondarily by both branched and unbranched Cyanophyta. Bacillariophyta (diatoms) were species rich (over 100 taxa), but were at all times relatively unimportant in the streams, although frequently dominant in the epipelon of Jacob's Lake. Species of Rhodophyta were locally abundant only in shaded habitats. Many epilithic and epiphytic species were "host" specific in their substrate preferences. Stream water in the North Alouette was slightly acid (pH 6-7) and nutrient poor, the relative order of anions being S0₄²⁻ > SiO₂ > CI⁻ >N0₃⁻ > PO₄³⁻ and cations Ca²⁺ = Na⁺ > Mg²⁺ > K > NH₄⁺ > Fe²⁺/³⁺, Mn²⁺, and Al³⁺ were not detected in the dissolved fraction. Other variables indicated this to be a rapidly flowing (often > 1m sec⁻¹), cool (2-18°C seasonally), poorly buffered (HCO₃⁻ = .06-.40 meq 1⁻¹), and highly heterogeneous environment. Stations along the stream gradient differed in conditions of slope, current velocity, degree of shading, and substrate size, but not in temperature, pH, and possibly nutrient chemistry. A principle coordinates analysis (P-Co-A) of seasonal succession at one station (Station 1) revealed a cyclic pattern characterized by sequences of gradual and abrupt changes in species composition. Temporal extinction of dominant species did not occur, as has been shown for phytoplankton populations in lakes. Current velocity, depth, temperature, CI⁻, and SO₄²⁻ were significantly correlated (P<0.05) with most of the seasonal variability in the algal community. A smaller amount of the seasonal change was correlated with the flux of dissolved cations. P-Co-A also exposed similarities between six stations within the watershed which were not consistent seasonally, and gave no evidence of distinct zones. Distribution of algal species within Station 1 in May shown by cluster analysis, occurred roughly in two groups, corresponding to near-shore and midstream habitats. The general heterogeneity of algal distribution and the occasional disturbance by flooding gave rise to periodic peaks in diversity, although many common species never became abundant. Hence, no clear-cut relation was realized between the physiochemical environment and species diversity. Hypotheses are generated, suggesting that (1) distribution of red algae was shade limited; (2) diatom dominance was limited by nutrient chemistry; (3) the even pattern of seasonal succession was interrupted by periodic events, such as nutrient pulses and floods; and (4) a large degree of species coexistence was provided by these periodic disturbances. / Science, Faculty of / Botany, Department of / Graduate

Pythium undulatum var. litorale Hohnk was found to infect Fucus distichus in the Squamish River estuary of southern British Columbia. This thesis adresses the questions of: 1.) whether this symbiosis can be found outside the Squamish River estuary, 2.) relationship of the infection within the estuary to the distribution of P. undulatum var. litorale in estuarine sediments, 3.) taxonomically defining those species associated with Fucus and/or in estuarine sediments, and 4.) the host parasite relationship as determined by means of histochemical and light microscope observations. Results indicated that outside the Squamish River estuary, associations between pythiaceous fungi and Fucus are uncommon in British Columbia coastal areas. Sampling of live and decaying Fucus plants from 10 field stations in British Columbia and Washington yielded only 4 species, the most common isolate being Phytophthora vesicula. Within the Squamish estuary, an association was found to exist between the distribution of P. undulatum var. 1itorale in the sediments and the distribution of infected Fucus plants. Sediment sampling from the Fraser River estuary, where Fucus does not occur, yielded P. undulatum var. litorale, suggesting that the fungus is probably indigenous to estuarine sediments. Numerous other species of Pythium were recovered from estuarine sediments, including P. butler i, P. carolinianum, P. catenulatum, P. gracile, P. torulosum , and P. volutum . Two taxa are described in detail. Pythium undulatum var. litorale was originally described by Hohnk (1953), but the varietal status was rejected by Waterhouse (1967). Arguments are presented for retention of the variety. Pythiogeten utriforme Minden is transferred to the genus Pythium and P. hohnkii is proposed as the nomen nova of this taxon. A discussion of the generic characteristics of the genus Pythiogeten is presented. In order to facilitate an understanding of the infection process by Pythium species, the anatomy and histochemistry of Fucus distichus were examined. Anatomically, F. distichus agrees with earlier reports of other species of Fucus. The internal structure of cells was found to agree with descriptions in earlier publications, although higher physode content was noted in F. distichus. Histochemical staining suggested that cell walls of Fucus are three layered; having an outer fucan-rich layer, a middle layer composed principally of alginic acid, and an innermost layer of cellulose. Several phenolic-indicating reagents were tested on both fresh and fixed/embedded Fucus tissue, resulting in some interesting new observations of phenolics in the matrix. The host-parasite interface of P. undulatum var. 1itorale and F. distichus was also examined by use of histochemistry and the light microscope. Macroscopically, the infection of F. distichus occurs behind the most recent dichotomy, and lesions are necrotic, firm (flaccid with age), and are pink-to-red in color. Microscopically, fungal hyphae are confined to the cortical and medullary regions. Hyphae appear to penetrate host cell walls by means of an enzymatic dissolution of the alginic acid and cellulosic portions of the cell wall. Use of the Periodic Acid/Schiff's reagent shows a distinct non-staining halo at the point where hyphae cross the cell wall. Pit connections between cortical cells were observed to break down with hyphae present in only one cell, suggesting that the fungus is capable of parasitizing several cells via digestion of pits. Gemmae were observed to form in both cortical and medullary cells. The response by Fucus to infection is an active one; a hypersensitivity reaction analagous to that of higher plants is observed. Cells in advance of fungal hyphae are observed to autolyse. Normally metabolically quiescent medullary filaments are observed to have an increase in general protein levels and to have increased physode content. Physodes become polarized within the medullary cells, and coalesce to form larger units, which are then delimited from the producing cell by a cross wall. The fate of these 'giant' physodes was not observed, but it is believed that these cells autolyse and release their phenolic contents to the matrix, as levels of phenolic-reactive material were observed to increase in this region. Coupled with the buildup,of phenolics in the matrix is a decrease in the fucan component of the matrix. Stress and tear lines appear between cells, and eventually this region serves as an abscission zone by which the infected portions are dropped out of the plant. Behind the abscission zone, medullary filaments undergo transverse divisions to form irregular, cuboidal cells which function as epidermis after abscission of the lesion occurs. / Science, Faculty of / Botany, Department of / Graduate