Source: 

                                   Mycotaxon 84:447-487.  2002.

                             Peter M. Letcher and Martha J. Powell 

                    “A Taxonomic Summary of Chytriomyces (Chytridiomycota)” 

 

1a. Sporangium tinted golden-orange to red ................................................2

1b. Sporangium hyaline...............................................................................3

2a. Rhizoidal system apophysate; filamentous rhizoids well developed, extensive,

      branched..................................................................................4. C. aureus

2b. Rhizoidal system apophysate; filamentous rhizoids absent.....7. C. cosmaridis

3a. Sporangia predominantly multioperculate (up to 10)...............................4

3b. Sporangia predominantly with one operculum........................................5

4a. Organism parasitic on Mortierella sp. ........................19. C. mortierellae

4b. Organism saprophytic on cellulose or pollen..........20. C. multioperculatus

5a. Zoospores non-guttulate, containing many small globules.........................6

5b. Zoospores guttulate, containing a single globule ......................................8

6a. Sporangia spherical or subspherical.................13. C. hyalinus v. granulatus

6b. Sporangia appendiculate, ovoid, or broadly pyriform..............................7

7a. Sporangial wall not ornamented............................16. C. macro-operculatus

7b. Sporangial wall ornamented with numerous long branched hairs.....................

...............................................................17. C. macro-operculatus v. hirsutus

8a. Sporangium interbiotic ............................................................................9

8b. Sporangium not interbiotic, but epibiotic ................................................10

9a. Sporangial wall smooth ...............................................................8. C. elegans

9b. Sporangial wall smooth ornamented with proximal collar-like undulations at the

       lower half of the sporangium .................................................2. C. annulatus

10a. Sporangium angular, appendiculate, or irregular......................................11

10b. Sporangium glubose, subglubose, or pyriform, but not angular.................19

11a. Sporangium with an apophysis................................................................12

11b. Sporangium without an apophysis...........................................................13

12a. Apophysis glubose to subglubose..........................................29. C. stellatus

12b. Apophysis an inflated tubular structure ...................................................13

13a. Zoospores swarming in an exogenous vesicle prior to release...3. C. appendiculatus

13b. Zoospores quiescent in a vesicle, which separates from the sporangium, prior to

        release .....................................................................................15. C. lucidus

14a. Sporangium ornamented with overlapping cupules .................23. C. poculatus

14b. Sporangium not ornamented, sporangial wall smooth ............................15

15a. Organism parasitic................................................................................16

15b. Organism saprophytic ..........................................................................18

16a. Parasitic or hyperparasitic on other chytrids .....................30. C. suburceolatus

16b. Parasitic on protozoa or algae ...............................................................17

17a. Parasitic on heliozoan Raphidiocystis lemani ........................11. C. heliozoicola

17b. Parasitic on diatoms Tabellaria flocculosa, T. fenestrata ....31. C. tabellariae

18a. Rhizoidal axis present, up to 8 µm diameter, with thinner, extensive but sparingly

        branched rhizoids ..............................................................27. C. rotoruaensis

18b. Rhizoidal axis present, but only slightly thicker than remaining rhizoids..1. C. angularis

19a. Sporangium ornamented with spines, apical teeth, or proximal collar-like undulations..

 ...................................................................................................................20

19b. Sporangium not ornamented .................................................................21

20a. Sporangial wall ornamented with simple or bifurcate spines, sporangium non-

        apophysate........................................................................28. C. spinosus

20b. Sporangial wall smooth, with 2 sharp teeth at apex, sporangium apophysate

        or not.................................................................................6. C. confervae

21a. Sporangium with discharge papillae or tubes .........................................22

21b. Sporangium without discharge papillae or tubes ....................................24

22a. In discharge, zoospores swarm in an exogenous vesicle...............9. C. fructicosus

22b. In discharge, zoospores not swarming or in an exogenous vesicle............23

23a. Zoospore discharge explosive; zoospores not within a vesicle or mucilage layer ......

....................................................................................................26. C. rhizidiomycis

23b. Zoospore discharge passive; zoospore ooze out in mass, enveloped in thin, slimy layer...

.....................................................................................................33. C. verrucosus

24a. Sporangium with an apophysis ................................................................25

24b. Sporangium without an apophysis............................................................29

25a. Sporangium with 1-20 nodular protuberances extending centripedally (inward) from

        the sporangial wall ..............................................12. C. hyalinus (syn. C. nodulatus)

25b. Sporangium without centripedal nodular protuberances.............................26

26a. Saprophytic on chitin..........................................................................12. C. hyalinus

26b. Parasitic...................................................................................................27

27a. Parasitic on Aphanomyces.................................................................22. C. parasiticus

27b. Parasitic on Pythium................................................................................28

28a. Resting spores spherical, smooth...........................................................14. C. laevis

28b. Resting spores spherical, reticulate.................................................24. C. reticulatus

29a. Sporangium pyriform.................................................................................30

29b. Sporangium globose or subglobose............................................................31

30a. Resting spores pyriform, tuberculate..........................................................10. C. gilgaiensis

30b. Resting spores spherical, smooth................................................................34. C. willoughbyi

31a. Resting spore spherical, with rough wall...............................................21. C. nagatoroensis

31b. Resting spore spherical, with smooth wall....................................................32

32a. Sporangial discharge passive, spores not in a vesicle............................25. C. reticulosporus

32b. Sporangial discharge with zoospores swarming in a vesicle...........................33

33a. Rhizoids sparse.........................................................................................5. C. closterii

33b. Rhizoids well-developed..............................................................................34

34a. Parasitic on Aphanomyces......................................................................22. C. parasiticus

34b. Saprophytic on pollen..................................................................................35

35a. Resting spore wall smooth.........................................................................32. C. vallesiacus

35b. Resting spore wall mammilose or verrucose..............................................18. C. mammilifer