Hendersonula toruloidea in glucose or organic residue media produced high yields of a humic acid-type polymer. As much as one third of the substances, including biomass synthesized by the fungus, consisted of the polymer. The primary phenolic constituents of the polymer are orcinol, 3,5-dihydroxybenzoic acid, and probably 2,3,5-trihydroxytoluene with smaller amounts of 2,6-dihydroxytoluene, m-hydroxybenzoic acid, 6-methylsalicylic acid, methylphloroglucinol, salicylic acid, 2,4-dihydroxytoluene, and several other phenols. Phenols derived from p-hydroxycinnamic acid were not found. A phenoloxidase was found in mature cells which rapidly oxidized mixtures of the phenols with the formation of polymers. The polymer is highly resistant to microbial degradation in soil and is similar to soil and other fungus humic acids with respect to elemental composition, exchange capacity, and total acidity. The fungus transforms or utilizes numerous phenols as carbon and energy sources.

Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1972. | A landscape unit approach based on use of airphotos was used for investigation of Deciduous Acacia Woodland in the Reserve. The approach was useful for indicating that a quantity of as few as 531 samples could be suitable for sampling woody vegetation over the large, 493 km² area, and for showing where the samples might advantageously be distributed. Use of the approach minimised the extrapolation of community boundaries for mapping purposes. Normal association analysis of the samples revealed the nine woody consociations present and provided quantitative data on species constancy and fidelity. These data were used towards explaining low levels of homogeneity within consociations, as well as some close floristic similarities found between consociations. The successful emergence of a species to dominance in a consociation was ascribed to the presence of a particular, described soil series or rock substrate. The distribution pattern of the consociations resembled a soil-vegetation catena on the landscape. The consociations were grouped into defined physiognomic categories of Open, Closed and Riverine Woodland Associations that were distributed according to three soil associations. The effects of soil factors, fire and the biota on physiognomy, notably secondary thicket encroachment, were discussed; and the relationship between climate and phenology was mentioned. A quantitative description of the grass communities based on normal analysis of stratified sample data revealed a retrogression whereby climax grasses are being replaced by mid-seral and pioneer grasses. The retrogression was ascribed to selective grazing by an increasingly large biomass of enumerated, indigenous herbivores. Some of the management recommendations offered were based on empirically calculated estimates of the weights of dry grass required annually by the grazing animals. Copies of topography, place names, geology, land surface and vegetation maps are provided. The text is supplemented by check lists of plants and animals recorded, by eight figures, 33 tables and 54 photos.

Atriplex polycarpa (Torr.) Wats. was a dominant, palatable shrub of the xeric Atripleto—Brometum disclimax in the San Joaquin valley of California. Overgrazing and agriculture during the past 100 years have restricted its present distribution to saline or fenced areas. Optimal germination temperatures (9—15°C) are close to those that prevail in nature in November, the month of utricle dispersal. Germination is rapid and can occur over a wide range of temperatures (3—33°C); it is reduced by light and NACl > 1%, but indifferent to temperature alternation and soil CaCO₃ content. It is unlikely that the bracteoles contain inhibitors. In a field plot in the Temblor Range of California, during a growing season with 115 mm precipitation, none of the seeds sown produced an established seedling, possibly because of competition by introduced annuals. Optimal growth conditions were 18—hour photoperiod, 24 ± 4°C. Growth at 12°C was quite slow. If conditions are favorable A. polycarpa can produce a large biomass, but it possesses a long juvenile stage of > 2 years prior to flowering. The base value of shoot water potential at no moisture stress is —18 bars, but this can be modified downward by pre—exposure to minor cycles of drought. This species can endure soil moisture below that which causes ultimate wilting or sunflower plants and can recover from a shoot water potential as low as —69 bars. Plants in nature, in August, exhibited a shoot water potential as low as —58 bars. This species was compared in a number of ways to Syrian ecological equivalents Haloxylon articulatum and Salsola vermiculata var. villosa.