Some Aspects of Morphology and Development in the Chytridiales

SUMMARYSingle-sporangium isolates of Chytridium ottariensis, Chytriomyces hyalinus, Phlyctochytrium powhatanensis, and Rhizophydium sphaero-carpum have a stable type of thallus development regardless of the growth medium or substrate used. However, medium is highly influential on the size range of sporangia and resting spores. Thallus growth on standard chytrid baits is epi-endobiotic and also interbiotic; resting spores produced on these baits occur on or in the substrate. Sporangium and resting spore size ranges for 17 isolates of C. hyalinus on a given medium were not significantly different Apophysis shape within any one strain on any medium was highly variable and ranged from spherical, davate, elongate, to catenulate. Both lid and flap opercula occurred in five of the 17 strains but in the remaining 12 the opercula were either flap or lid but not both. Location of thallus, position of resting spore, and presence of catenulate apophyses were not constant within any strain for any medium or substrate.