1a. Chitinophilic or keratinophilic; rhizoids with or without constrictions; sporangial exit
      papillae one to four, low and dome-shaped or conical and more conspicuous;
      resting spore wall “spiny” (i.e., with peg-like projections), roughened or smooth in
      appearance......................................................................................................2

1b. Inhabiting cellulosic debris; rhizoids showing constrictions; sporangial exit papilla one
      or two, often becoming elongated and tube-like; resting spores smooth-walled or
      absent..............................................................................................................4

2a. Resting spore wall with distinct pegs or spine-like processes; rhizoids relatively
      thin to relatively thick-walled, but not showing appreciable constrictions;
      exo-operculum up to 18 µm in diameter, the rim flush on exit papilla orifice
      (or sporangial surface); zoospores usually less than 5 µm in diameter..................3

2b. Resting spore wall smooth to rugose or verrucose; rhizoids thick-walled, distinctly
      constricted at intervals ("catenulate" appearance); exo-operculum up to 30 µm
      in diameter, appearing to "sit" on a raised, cushion-like area; zoospores usually
      more than 5 µm in diameter...............................................................................3. K. dubius

3a. Resting spore ornamentations usually straight, blunt, peg-like, relatively sparse;
      released zoospores at first swarming in an evanescent vesicle outside the sporangium;
      zoospore flagellum 24-26µm in length; exit papillae often barely rising above
      sporangial surface; sporangia intercalary............................................................1. K. asterocystis

3b. Resting spore ornamentations often spiny, acute, hamate, numerous; released
      zoospores not contained in a vesicle, but may be temporarily immersed in
      extruded granular matrix material; zoospore flagellum 10-13 µm long; exit
      papillae usually more elevated; sporangia intercalary or stalked..........................2. K. curvispinosus

4a. Resting spore ornamentations usually straight, blunt, peg-like, relatively sparse;
      released zoospores at first swarming in an evanescent vesicle outside the
      sporangium; zoospore flagellum 24-26µm in length; exit papillae often barely
      rising above sporangial surface; sporangia intercalary.........................................4. K. marylandicus

4b. Resting spore ornamentations often spiny, acute, hamate, numerous; released
      zoospores not contained in a vesicle, but may be temporarily immersed in
      extruded granular matrix material; zoospore flagellum 10-13 µm long; exit papillae
      usually more elevated; sporangia intercalary or stalked.......................................5. K. exooperculatus