THE SPECIES OF CHYTRIOMYCES: TAXONOMIC DESCRIPTIONS, REFERENCES AND DISTRIBUTION

 

 

1. CHYTRIOMYCES ANGULARIS Longcore

            Mycologia 84:443, figs. 1-29. 1992.

            PLATE 6, figs. 175-179

            Vegetative: Thallus epibiotic. Reproductive: Sporangium longer than wide, ellipsoid, gibbose or angular, hyaline, diameter 12 µm, height 22 µm, sessile or having an extramatrical stalk; sporangial wall smooth, with rounded to angular projections. Rhizoidal system: Rhizoidal axis only slightly thicker than remainder of the rhizoids, rhizoids branch from main axis at some distance from the sporangium. Zoospore, discharge: Operculum present, not persistent, apical or subapical, saucer shaped, diameter 7-8 µm, discharge pore single; discharge vesicle absent, zoospore discharge as an initial burst, zoospores quiescent for 1-2 minutes after sporangial dehiscence and prior to motility, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores ovoid, 4-5 µm in diameter, single lipid globule hyaline, flagellum 30 µm long. Zoospore, ultrastructure: Longcore 1992. Resting spore: Epibiotic, ovoid, angular or gibbose, thick-walled, smooth, hyaline. Ecology and Distribution: From water, on pollen, Longcore (loc. cit.: Maine), from soil, Letcher and Powell (unpublished observation, Virginia, North Carolina, and Utah), US.

2. CHYTRIOMYCES ANNULATUS Dogma

            Nova Hedwigia 18:349, figs. 1-18. 1969.

            PLATE 6, figs. 163-168

            Vegetative: Thallus epibiotic or interbiotic. Reproductive: Sporangium pyriform or obpyriform, hyaline, diameter 10-31 µm, height 14-38 µm, having an extramatrical stalk; sporangial wall ornamented with 3-8 proximal collar-like annulations. Rhizoidal system: Apophysis spherical (not necessarily as a subsporangial swelling), diameter 8-15 µm, or saccate, 4-7 µm × 10-15 µm; filamentous rhizoids limited, sparsely branched. Zoospore, discharge: Operculum present, persistent, apical, saucer shaped, diameter 7-10 µm, not rigid after discharge, discharge pore single; discharge vesicle absent, zoospore discharge as a mass, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 4.7-6.5 µm in diameter, single lipid globule hyaline, flagellum 29-30 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Spherical or subspherical, 8-15 µm, hyaline, on an extramatrical stalk, containing a single globule. Ecology and Distribution: From leaf litter and soil samples, saprophytic on pine pollen, sweet gum pollen, and snake skin, weakly parasitic on Rhizophydium coronum sporangia and Rhizophlyctis rosea rhizoids, Dogma (loc. cit.: Michigan, Wisconsin, North Carolina, Maine, Virginia, New Hampshire, Vermont), on pollen, Letcher and Powell (2001:1031; 2002:766, Virginia), US; on pollen, Booth and Barrett (1971:362, E. Arctic), Lee (2000:60, Manitoba), CANADA; from water, on chitin, Czeczuga and Godlewska (1998), POLAND.

            Based on actual observations of this organism (Letcher and Powell 2001, 2002), the species is emended as follows: Chytriomyces annulatus Dogma emend. Resting spore spherical, diameter 8-15 µm, subspherical or ovoid, 5-8 µm × 7-12 µm, the wall smooth or rarely with a single proximal collar-like annulation; with an extramatrical stalk and an endobiotic, spherical apophysis; contents of the resting spore a single large central hyaline globule occasionally surrounded by several smaller globules.

3. CHYTRIOMYCES APPENDICULATUS Karling

            Bull. Torrey Bot. Club 74:335, figs. 16-37, 43-48. 1947.

            PLATE 3, figs. 70-74

            Vegetative: Thallus epibiotic. Reproductive: Sporangium highly variable in size and shape: ovoid, pyriform, transversely flattened or reniform, hyaline to brown, diameter 10-80-(250) µm, height 10-50 µm, sessile; sporangial wall appendiculate or smooth. Rhizoidal system: Subsporangial swelling rarely present; main rhizoidal axis up to 18µm in diameter; filamentous rhizoids well developed, branched, coarse. Zoospore, discharge: Operculum present, not persistent, apical, subapical or lateral, saucer shaped, diameter 6-14 µm, discharge pore single; discharge vesicle present; zoospore discharge as a mass, zoospores swarming in vesicle outside sporangium before dispersal, vesicle separating from sporangium, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores ovoid, 4-6 µm in diameter, single lipid globule hyaline, flagellum 28-32 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical, diameter 10-25 µm, or appendiculate, thick-walled, smooth, brown, and coarsely granular with a central vacuole; upon germination functions as a prosporangium . Ecology and Distribution: In water and soil, on chitin, Karling (loc. cit., Virginia, New Jersey, New York, Connecticut), in water, on chitin, Miller (1965:223, Virginia), from soil, Dogma (1969:355, Michigan), US; from soil and water, on chitin, Willoughby (1961:306), from soil, on chitin, Willoughby (1962:122), UK; from soil, on pollen and keratin, Booth (1971b:951, British Columbia), CANADA; from soil, on chitin, Karling (1967:122), NEW ZEALAND; from water, on chitin and keratin, Kiran (1993), INDIA.

            “One of the peculiarities of this very distinct species is the tendency for some sporangia to form large amounts of “slime” beneath the area of discharge. In some material no vesicle was formed” (Sparrow 1960:544).

4. CHYTRIOMYCES AUREUS Karling

            Am. J. Bot. 32:363, figs. 28-45. 1945.

            PLATE 1, figs. 6-11

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical or ovoid, golden-red, diameter 8-40 µm, sessile, sporangial wall smooth. Rhizoidal system: Apophysis spherical or subspherical, diameter 3-6 µm, filamentous rhizoids well developed, branched or coarse. Zoospore, discharge: Operculum present, not persistent, apical, saucer shaped; discharge pore single; discharge vesicle present; zoospores swarming in vesicle outside sporangium before dispersal; vesicle continuous with sporangium, zoospore discharge as a mass, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores ovoid, 3-3.5 µm in diameter, single lipid globule golden-red, flagellum 22-25 µm long. Zoospore, ultrastructure: Dorward and Powell 1982, 1983. Resting spore: Epibiotic, spherical, 6-20 µm, or ovoid, 6-10 µm × 12-16 µm, thick-walled, smooth, golden brown, with numerous closely packed granules or globules.  Ecology and Distribution: In water, in exuviae of mayflies and on chitin, Karling, (loc. cit., Connecticut, New York, Virginia), on pollen, Miller (1965:223, Virginia), in soil, on chitin, Dogma (1969:357, Michigan), Hasija and Miller (1970:1034, Ohio), US; in water, on chitin, keratin, and cellulose, Willoughby (1959:67, 1961:306), UK; in soil, on chitin, Karling (1967:121), NEW ZEALAND; in soil, on cellulose, Hassan (1993:35), EGYPT; in water, on chitin, Karling (loc. cit.), BRAZIL.

5. CHYTRIOMYCES CLOSTERII Karling

            Bull. Torrey Bot. Club 76:352, figs. 1-5. 1949.

            PLATE 1, figs. 29-35

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical or pyriform, hyaline, diameter 5-25 µm, sessile; sporangial wall smooth. Rhizoidal system: Rhizoids a single, sparsely branched axis, sometimes extending to 120 µm. Zoospore, discharge: Operculum present, not persistent, apical, saucer shaped, diameter 4-6 µm, discharge pore single, with a discharge papilla; discharge vesicle present, zoospores swarming in vesicle outside sporangium before dispersal, vesicle continuous with sporangium, zoospore discharge as a mass, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 2-2.5 µm in diameter, single lipid globule hyaline, flagellum 9-12 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical or ovoid, 7-12 µm, hyaline, thick-walled, smooth, with a large central globule surrounded by several smaller ones. Ecology and Distribution: In water, parasitic on Closterium rostratum Karling (loc. cit.), US.

            “Apparently confined to one host species. It does not attack other species of Closterium or members of other genera of green algae” (Sparrow 1960:541).

 

6. CHYTRIOMYCES CONFERVAE (Wille) Batko

            Zarys Hydromikologii p. 210, fig. 319. 1975.

            Chytridium confervae (Wille) Minden, Kryptogamenfl. Mark Brandenburg, 5:368. 1911 (1915).

            Phlyctochytrium confervae (Wille) Lemmerman, Abhandl. Naturwiss. Vereins Bremen 17:194. 1901.

            Rhizidium confervae Wille, Vidensk. Selsk. Skr. Christiana (Mat.-Nat. Kl.): 1, figs. 1–3. 1899.

            PLATE 3, figs. 89-95

            Vegetative: Thallus epibiotic. Reproductive: Sporangium ovoid, hyaline, diameter 15-32 µm, height 18-40 µm, sessile, sporangial wall smooth, with 2 sharp, curved teeth at apex.  Rhizoidal system: Subsporangial swelling broadly fusiform, 13.5-24 µm long × 4.3-5.6 µm broad, filamentous rhizoids well developed, sparsely branched. Zoospore, discharge: Operculum present, persistent, apical, saucer shaped, diameter 10-12 µm, discharge pore single; discharge vesicle present; zoospores swarming in vesicle outside sporangium before dispersal; vesicle continuous with sporangium; zoospore discharge as a mass, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 5-6 µm in diameter, single lipid globule hyaline, flagellum 27 µm long. Zoospore, ultrastructure: Barr and Hartmann 1976. Resting spore: Epibiotic or endobiotic, spherical or ovoid, thick-walled, smooth, hyaline or light yellow. Ecology and Distribution: In water, parasitic on Tribonema, Wille (1899:1), SWEDEN; Scherffel (1925:32), HUNGARY; Sparrow (1939:124), US; Rieth (1951:259), GERMANY; Sparrow (1957:532), Canter (1962:532), UK; Barr (1975:168, Ontario), Bandoni and Barr (1976:222, British Columbia), Barr and Hadland-Hartmann (1978:890, Ontario), CANADA; Batko (loc. cit.), POLAND.

            Batko (1975) transferred Chytridium confervae (Wille) Minden to the genus Chytriomyces because of observation of an epibiotic resting spore.

7. CHYTRIOMYCES COSMARIDIS Karling

            Sydowia, Annales Mycologici Ser. II, 20:119, figs. 1-7. 1967.

            Sphalm. Chytriomyces cosmarii, Index of Fungi 3:483.

            PLATE 2, figs. 36-40

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical or subspherical and slightly flattened at the base, diameter 12-42 µm, golden-orange, sessile, having an internal, basal peg; sporangial wall smooth, surrounded by a slightly orange to yellow halo 9-12 µm thick. Rhizoidal system: Apophysis spherical or subspherical, diameter 6-9 µm, filamentous rhizoids lacking. Zoospore, discharge: Operculum present, persistent, apical or lateral, saucer shaped, diameter 6-10 µm, with a broad opaque to hyaline zone of substance or matrix underneath, discharge pore single; discharge vesicle present, zoospores swarming in vesicle outside sporangium before dispersal; vesicle continuous with sporangium, zoospore discharge as a mass, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 2-2.6 µm in diameter, with a single brilliantly refractive yellow-orange lipid globule, flagellum 11 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Spherical or ovoid, 8-12 µm diameter, thick-walled, smooth, hyaline to light yellow and surrounded by a slightly yellowish halo 6-8 µm thick; contents coarsely granular with a single large central globule. Ecology and Distribution: From soil, a hillside sheep paddock, parasitic on Cosmarium sp., Karling (loc. cit.: Taita, Wellington Province), NEW ZEALAND; from water, Czeczuga (1994), POLAND.

            The original spelling of the epithet was “cosmarii”, which Karling believed to be a mistake and in error (sphalmate); Karling (1967) attempted to correct the error to “cosmaridis” by making an indelible hand correction on circulated reprints of the original description. Index of Fungi (3:483) retained the original spelling. Karling (1977) validated “cosmaridis” by using that epithet in his revisionary treatment of the Chytridiomycetes.       

 

8. CHYTRIOMYCES ELEGANS (Ingold) Dogma

            Philippine J. Biol. 5:136. 1976.

            Amphicypellus elegans Ingold, Trans. Br. Mycol. Soc. 27:93-97. 1944.

            PLATE 1, figs. 22-28

            Vegetative: Thallus interbiotic. Reproductive: Sporangium spherical, hyaline, diameter 8-16 µm, sporangial wall smooth; sporangium surrounded by a mucilaginous secretion. Rhizoidal system: Apophysis spherical, diameter 3-5 µm, filamentous rhizoids well developed, branched. Zoospore, discharge: Operculum present, persistent, apical or subapical, saucer shaped; discharge pore single; discharge vesicle present, zoospores swarming in vesicle outside sporangium before dispersal; vesicle continuous with sporangium, zoospore discharge as a mass, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 3.5-4.5 µm in diameter, single lipid globule hyaline. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical, thick-walled, yellow, ornamented with stiff, rod-like hairs. Young resting spore surrounded by a halo of colorless material detectable with gentian violet in aniline water; immediately beneath the resting spore a swelling resembling an apophysis, from which the rhizoidal system emerges; resting spore thallus surrounded by a mucilaginous secretion. Ecology and Distribution: Saprophytic on dead cells of Ceratium hirundinella and Peridinium, Ingold (loc. cit.), UK; Canter (1951:151), UK, DENMARK, SWEDEN, ITALY; parasitic on Ceratium, Paterson (1958:91), US; from soil, on green algae, Dogma (1976:136), PHILIPPINES.

            Dogma (1976) moved the type genus of Amphicypellus elegans into Chytriomyces. Because the former was described first, and hence would have nomenclatural precedence, Chytriomyces needs to be conserved formally.

9. CHYTRIOMYCES FRUCTICOSUS Karling

            Bull. Torrey Bot. Club 76:353, figs.18-52. 1949.

            PLATE 3, figs. 79-83

            Vegetative: Thallus epibiotic. Reproductive: Sporangium appendiculate, spherical, pyriform or irregular, hyaline or light brown, diameter 17-35 µm, sessile, sporangial wall appendiculate. Rhizoidal system: Apophysis subspherical, elongate, fusiform or angular, diameter 8-20 µm; filamentous rhizoids well developed, branched, with a bushy appearance, branches occasionally extending for a distance of 275 µm. Zoospore, discharge: Operculum present, not persistent, apical, saucer shaped or dome shaped, diameter 4-8 µm, discharge pores one or two, discharge papillae present, one or two, discharge tubes present, one or two; discharge vesicle present, zoospores swarming in vesicle outside sporangium before dispersal, vesicle continuous with sporangium, zoospore discharge as a mass, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores ovoid, 4-6 µm in diameter, single lipid globule hyaline. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical, ovoid, or angular, 18-30 µm, verrucose or spiny, light amber or greenish-brown, contents finely granular. Ecology and Distribution: From water and soil, on chitin, Karling (loc. cit.), US.

            “About 18 per cent of the sporangia and resting spores were formed from thalli which had developed from the germ tube of the zoospore and not by the expansion of the zoospore body itself. The type of development seemed dependent upon the behavior of the nucleus of the encysted zoospore. If it remained in the cyst a Rhizidium-like development ensued, whereas if it passed into the germ tube the less typical method of development was undergone. The sporangia are quite variable in shape and [the rhizoid] may have one to three apophyses.

            As noted by Karling (1947) in other species of Chytriomyces, a single nucleus is present in the sporangial rudiment until the latter reaches full size” (Sparrow 1960:545).

10. CHYTRIOMYCES GILGAIENSIS Willoughby

            Arch. Mikrobiol. 52:102, figs. 6 a-l. 1965.

            PLATE 2, figs. 51-56

            Vegetative: Thallus epibiotic. Reproductive: Sporangium pyriform, hyaline, diameter 5-15 µm, height 8.5-20 µm, sessile, sporangial wall smooth. Rhizoidal system: Haustorium lobed. Zoospore, discharge: Operculum present, persistent, apical or lateral, saucer-shaped, diameter 5-8.5 µm; discharge pore single; discharge vesicle unknown, zoospore discharge unknown, zoospore motility unknown. Zoospore, microscopic: Zoospores with a single hyaline lipid globule. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, pyriform, 12 µm diameter, hyaline, thin-walled, tuberculate, containing 1-3 large hyaline globules. Ecology and Distribution: From soil from a gilgai depression, parasitic on Nowakowskiella crassa Karling, Willoughby (loc. cit.: Victoria), AUSTRALIA.

11. CHYTRIOMYCES HELIOZOICOLA Canter

            Trans. Br. Mycol. Soc. 49:633, fig.1, a-s. 1966.

            PLATE 2, figs. 57-61

            Vegetative: Thallus epibiotic. Reproductive: Sporangium sessile, ovoid or broadly ovoid, diameter 8.5-22 µm, hyaline, 10-24 µm high × 8.5-22 µm broad , sporangial wall smooth. Rhizoidal system: Filamentous rhizoids limited, lobose tufts arising from a single axis. Zoospore, discharge: Operculum present, not persistent, apical, rarely lateral, 5-13 µm diameter, saucer shaped, discharge pore single; presence or absence of discharge vesicle, and mode of zoospore discharge unknown. Zoospore, microscopic: Zoospores spherical, 2.5-3 µm in diameter, hyaline, containing a single anterior, spherical, highly refractive lipid globule and a single posterior, less refractive, ovoid body whose longer axis is set at right angles to the direction in which the zoospore moves, flagellum 19 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical, 5-10 µm diameter, hyaline, thick-walled, smooth, containing 1-2 large refractive globules; asexually formed. Ecology and Distribution: From lake plankton, parasitic on the heliozoan Raphidiocystis lemani Penard, Canter (loc. cit.: Esthwaite Water and Windermere, English Lake District), UK.

 

12. CHYTRIOMYCES HYALINUS Karling (TYPE)

            Am. J. Bot. 32:363, figs. 46-61. 1945.

             Chytriomyces hyalinus emend. Bostick 1968. J. Elisha Mitchell Sci. Soc 84:94-99.

            Synonymy: Chytriomyces nodulatus Haskins, Trans. Br. Mycol. Soc. 29:137, text figs. 1-8. 1946.

            PLATE 1, figs. 1-5 (C. hyalinus); PLATE 1, figs. 16-21 (C. nodulatus)

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical, hyaline, diameter 10-60 µm, sessile, sporangial wall smooth. Rhizoidal system: Apophysis spherical, subspherical, elongate, or fusiform, diameter 3-7 µm; filamentous rhizoids well developed, branched, coarse, extending for a distance of 300 µm. Zoospore, discharge: Operculum present, not persistent, apical or subapical, saucer shaped, diameter 8-16 µm, discharge pore single; discharge vesicle present, zoospores swarming in vesicle outside sporangium before dispersal; vesicle continuous with sporangium, zoospore discharge as a mass, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores ovoid, 3-3.5 µm in diameter, single lipid globule hyaline, flagellum 18-20 m long. Zoospore, ultrastructure: Dorward and Powell 1982, 1983, Powell 1983, 1994. Resting spore: Epibiotic and endobiotic, spherical, 10-20 µm diameter, ovoid, pyriform, clavate, elongate, or angular, thick-walled, smooth, light brown; contents a large central refractive globule surrounded by a few to several smaller ones; sexually formed, functioning as a prosporangium in germination. Ecology and Distribution: In water, on chitin, Karling (loc. cit., Connecticut, New York, Virginia), on chitin, keratin, and pollen, Miller (1965:223, Virginia), on pollen, Bostick (1968:94, North Carolina), Hasija and Miller (1970:1035, Ohio), from soil, on pollen, Booth (1971a:939, Oregon, California, Nevada), from soil, Moore and Miller (1973:147, Ohio), in water, Roane and Paterson (1974:149, Virginia), in water, on pollen, Sparrow and Lange (1977:1887, Michigan), from soil, on pollen, Letcher and Powell (2001:1031; 2002:766, Virginia), US; from soil, on chitin, Sparrow (1957:532), from soil and water, on chitin, Willoughby (1961:306), from soil, on chitin and keratin, Willoughby (1962:122), UK; from soil, on pollen, Booth (1969:143, 1971c:198, British Columbia), on chitin, Booth (1971b:954, British Columbia), CANADA; from water, on chitin, Karling (loc. cit.), BRAZIL; from soil, on chitin, keratin, and cellulose, Karling (1967:121), NEW ZEALAND; from soil, on keratin, Karling (1981:656), VENEZUELA; on chitin, Karling (1966:57), Das-Gupta (1982:213), INDIA; from soil on chitin, keratin, and cellulose, Karling (1987:142), TRINIDAD, PANAMA; on chitin, Karling (1968:176), Pitcairn Island, OCEANIA; from soil, on chitin, Willoughby (1965:103), AUSTRALIA, from water, on pollen, Chen and Chien (1995:238), TAIWAN.

            “Common in bogs in Michigan; nodulate as well as smooth-walled sporangia were observed.” (Sparrow 1960:541). As such, the species was synonymized with Chytriomyces nodulatus Haskins. “This species frequently occurs in company with Polychytrium aggregatum on purified shrimp chitin bait” (Sparrow 1960:541).

13. CHYTRIOMYCES HYALINUS v. GRANULATUS Karling

            Sydowia, Annales Mycologici Ser. II, 20:120, figs. 8-15. 1967.

            PLATE 1, figs. 12-15

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical or subspherical, hyaline, diameter 12-120 µm, sessile, sporangial wall smooth. Rhizoidal system: Apophysis spherical, main axis 6-16 µm at base, filamentous rhizoids well developed, branched or coarse, extending for distances up to 400 µm. Zoospore, discharge: Operculum present, persistent, apical or subapical, saucer shaped, diameter 7-19 µm; discharge pore single; discharge vesicle present, zoospores swarming in vesicle outside sporangium before dispersal; vesicle continuous with sporangium, zoospore discharge as a mass, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical or slightly ovoid, 5-6 µm in diameter, hyaline, with several small refractive lipid globules, flagellum 22-26 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical, 8-18 µm diameter, ovoid, 6-9 µm × 10-16 µm, or irregular; thick-walled, smooth, light brown, containing one or more large central refractive globules surrounded by several smaller ones. Ecology and Distribution: From soil, saprophytic on bleached corn leaves, chitin, and snake skin, Karling (loc. cit.), NEW ZEALAND; on cellulose, Karling (1968:176), Cook Islands, OCEANIA.

            “This variety was widely distributed in New Zealand, and strikingly similar to C. hyalinus, except for its slightly larger non-guttulate zoospores. Also, its sporangia attained greater size [than C. hyalinus] and were usually non-apophysate. While C. hyalinus has a predilection for chitinic substrata this variety occurred more commonly on cellulosic substrata such as corn leaves and onion skin, although it grew to some extent on snake skin and shrimp chitin” (Karling loc. cit.).

14. CHYTRIOMYCES LAEVIS Karling

            Nova Hedwigia 44:137, figs. 1-18. 1987.

            PLATE 5, figs. 131-136

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical or obpyriform, hyaline, diameter 10-30 µm, sessile, sporangial wall smooth. Rhizoidal system: Apophysis present as a haustorium, spherical, diameter 2.5-4 µm, with no additional filamentous rhizoids. Zoospore, discharge: Operculum present, persistent, apical, saucer shaped, diameter 8-26 µm, discharge pore single; discharge vesicle absent; zoospore discharge as a mass, zoospore motility extrasporangial only.  Zoospore, microscopic: Zoospores spherical, 4-5 µm in diameter, single lipid globule hyaline. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical, 8-20 µm diameter, hyaline, thick-walled, smooth, with a large central globule surrounded by smaller ones. Ecology and Distribution: From a soil-water culture collected at a stream bank, parasitic on Pythium sp. growing on snakeskin, Karling (loc. cit.), PANAMA.

 

15. CHYTRIOMYCES LUCIDUS Karling

            Bull. Torrey Bot. Club 76:353, figs. 6-17. 1949.

            PLATE 3, figs. 75-78

            Vegetative: Thallus epibiotic. Reproductive: Sporangium transversely flattened or reniform, hyaline, diameter 28-66 µm, height 18-44 µm, sessile, sporangial wall smooth. Rhizoidal system: Subsporangial swelling present, filamentous rhizoids well developed, coarse, often extending for a distance of 400 µm and becoming thick-walled with age. Zoospore, discharge: Operculum present, not persistent, apical, saucer shaped, diameter 4-8 µm, discharge pore single, discharge papilla one; discharge vesicle present, zoospores quiescent in vesicle outside sporangium before dispersal, vesicle separating from sporangium, zoospore discharge as a mass, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores ovoid, 5.8-6.2 µm in diameter, with a single hyaline lipid globule. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, ovoid, 15-18 µm × 20-25 µm, hyaline, containing numerous angular refractive bodies; thick-walled, smooth. Ecology and Distribution: From soil and water, on cellulose, Karling (loc. cit., Maryland, Virginia), US.

 

16. CHYTRIOMYCES MACRO-OPERCULATUS Karling

            Nova Hedwigia 34:652, figs. 24-38. 1981.

            PLATE 4, figs. 120-124

            Vegetative: Thallus epibiotic. Reproductive: Sporangium appendiculate, ovoid, or broadly pyriform, hyaline, diameter 10-124 µm, height 16-160 µm, predominantly sessile, rarely stalked and subtended by a swelling, sporangial wall appendiculate, smooth. Rhizoidal system: Apophysate or nonapophysate; basal rhizoidal axis 4-8 µm diameter, usually arising at one or more places on the sporangium; filamentous rhizoids well developed, branched, coarse, extending for distances up to 80 µm. Zoospore, discharge: Operculum present, persistent, apical or lateral, saucer shaped, diameter 5-57 µm, discharge pore usually single, sometimes 2 or 3, up to 57 µm diameter; discharge vesicle present, zoospores swarming in vesicle outside sporangium before dispersal; vesicle continuous with sporangium; zoospore discharge as a mass, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 4.5-5 µm in diameter, single lipid globule with grayish granular contents, flagellum 18-22 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical, ovoid, angular, thick-walled, appendiculate, 7-40 µm diameter, reddish-brown. Ecology and Distribution: From soil, saprophytic on cellophane and bleached cotyledons of corn, Karling (loc. cit.), VENEZUELA.

 

17. CHYTRIOMYCES MACRO-OPERCULATUS v. HIRSUTUS Karling

            Nova Hedwigia 34:655, figs. 39-45. 1981.

            PLATE 4, fig. 125

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical, ovoid, or pyriform, diameter 54-60 µm, height 72-84 µm, sessile, sporangial wall appendiculate and ornamented, bearing numerous long, branched hairs which may extend for distances up to 600 µm in the surrounding water and often form a dense weft of filaments. Rhizoidal system: Non-apophysate, rhizoidal axes up to 12µm diameter, usually at the base of the sporangium, sometimes at the apex and sides, with irregular convolutions; filamentous rhizoids well developed, branched, extending for distances up to 400 µm. Zoospore, discharge: Operculum present, persistent, apical or lateral, dome shaped, diameter 12-18 µm, discharge pore usually single, sometimes 2 or 3; discharge vesicle present, zoospores swarming in vesicle outside sporangium before dispersal, vesicle continuous with sporangium, zoospore discharge as a mass, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 4.5-5 µm in diameter, lipid globules many, hyaline. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical, 4.5-5 µm diameter, bearing abundant coarse hairs, brown, with numerous granules which may fuse and form several refractive globules. Ecology and Distribution: From soil, saprophytic on cellophane, Karling (loc. cit.), VENEZUELA.

            “Except for its hirsute sporangia and smaller opercula, the development and general morphology of this species resemble those of C. macrooperculatus, and for that reason it is regarded as a separate variety” (Karling loc. cit.).

 

18. CHYTRIOMYCES MAMMILIFER Persiel

            Arch. Mikrobiol. 36:299, figs. 9, 10. 1960.

            PLATE 4, figs. 106-110

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical or ovoid, hyaline, diameter 7-35 µm, sessile, sporangial wall smooth. Rhizoidal system: Filamentous rhizoids well developed, branched. Zoospore, discharge: Operculum present, persistent or not persistent, apical, dome shaped or collapsing after dehiscence, diameter 7-35 µm, discharge pore single; discharge vesicle present; zoospores swarming in vesicle outside sporangium before dispersal; vesicle continuous with sporangium, zoospore discharge as a mass, zoospore motility both intersporangial and extrasporangial. Zoospore, microscopic: Zoospores spherical, 3.5-4.5 µm in diameter, single lipid globule hyaline, flagellum 15-18 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical, 7-20 µm diameter, hyaline, with a single large refractive globule, thick-walled, bullate or mammilose, bullae hyaline, 3-4 µm in length, 2-3 µm diameter, but smaller in culture. Ecology and Distribution: From soil (4000 m), saprophytic on pollen, Persiel (loc. cit.), ECUADOR; Johnson (1971:201), ICELAND.     

            Chytriomyces rhizidiomycis (Dogma) also has spherical, verrucose to bullate resting spores, which however, contain a compact mass of uniform-sized globules, and a small, eccentric vacuole (Dogma 1983). Regarding spore discharge, Johnson (1971) observed zoospores escaping without swarming in a vesicle.

19. CHYTRIOMYCES MORTIERELLAE Persiel

            Arch. Mikrobiol. 36:299, figs. 6, 7. 1960.

            PLATE 5, figs. 137-140

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical or subspherical, hyaline, diameter 7-40 µm, sessile, sporangial wall smooth. Rhizoidal system: Rhizoids filamentous, limited, finely branched. Zoospore, discharge: Operculum present, not persistent, apical, subapical, or lateral, dome shaped, (1)3 - 4(7) discharge pores, zoospores discharging through 1-2 exit orifices, remaining opercula often folded into the sporangium after discharge; discharge vesicle present, zoospore discharge as a mass, zoospores swarming in vesicle outside sporangium before dispersal, vesicle continuous with sporangium, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores ovoid, 2.5-3.5 µm in diameter, hyaline, with a single, eccentric, 1-1.5 µm diameter lipid globule, flagellum 17 µm long, zoospores elliptical when swimming. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical, 4-15 µm, thick-walled, smooth, hyaline. Ecology and Distribution: From soil, parasitic on Zygomycetes (Mortierella sp., Zygorhynchus sp., Mucor sp.), causing hypertrophy of infected hyphae, Persiel (loc. cit.) AUSTRIA.

20. CHYTRIOMYCES MULTIOPERCULATUS Sparrow and Dogma

            Arch. Mikrobiol. 89:193, fig. 5. 1973.

            PLATE 5, figs. 141-144

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical, subspherical,  ellipsoid, or angular, hyaline, diameter 10-38 µm, height 9.5-40 µm, sessile or having an extramatrical stalk, sporangial wall smooth. Rhizoidal system: Apophysis angular, diameter 2-8 µm, filamentous rhizoids limited, sparsely branched. Zoospore, discharge: Operculum present, persistent or not persistent, apical, subapical, or lateral, saucer shaped, diameter 2-8 µm, discharge pores three or more (up to 10), discharge papillae present, the apices of which during the later stages of sporangial maturation become circumcisely dehisced but remain attached by a narrow collar of inner wall material to the discharge orifice; discharge vesicle absent, zoospore discharge as an explosive burst, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 3.5-4 µm in diameter, hyaline, with a single large, somewhat basal lipid globule, flagellum 20 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Unknown. Ecology and Distribution: From soil, on pollen, Sparrow and Dogma (loc. cit.), DOMINICAN REPUBLIC.

            This species name is hyphenated as “multi-operculatus” in Index of Fungi (4:208).   

           

21. CHYTRIOMYCES NAGATOROENSIS Konno

            Sci. Rept. Tokyo Kyoiku Daigaku Sect. B, 14:253, pl. 4, fig. X. 1972.

            PLATE 2, figs. 41-44

            Vegetative: Thallus epibiotic. Reproductive: Sporangium subspherical, hyaline, diameter 8-30 µm, height 7-25 µm, having a persistent zoospore case basally, sessile, sporangial wall smooth. Rhizoidal system: Filamentous rhizoids limited, sparsely branched, tufted. Zoospore, discharge: Operculum present, not persistent, apical or lateral, saucer shaped, diameter 5-9 µm, discharge pores one or two, discharge papillae present, one or two; discharge vesicle unknown, zoospore discharge unknown, zoospore motility unknown.  Zoospore, microscopic: Zoospores ovoid, 3.5 µm in diameter, 4-6 µm in length, single lipid globule hyaline, flagellum 20-22 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Spherical to subspherical, 12-13 µm diameter, hyaline, thick-walled, rough. Ecology and Distribution: From water, weakly parasitic on Spirogyra sp., Konno (loc. cit.: Nagatoro, Saimata Prefect), JAPAN.

            “This species somewhat resembles Chytriomyces closterii Karling (1947), but it differs in several features, such as zoospore dimension, presence of zoospore case, number of papillae, tufted character of the rhizoid, and algal host” Konno (loc. cit.).

22. CHYTRIOMYCES PARASITICUS Karling

            Bull. Torrey Bot. Club 74:334, figs.1-15. 1947.

            PLATE 5, figs. 145-150

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical or ovoid, hyaline, diameter 8-30 µm, sessile, sporangial wall smooth. Rhizoidal system: Apophysis spherical or angular, diameter 3-6 µm, filamentous rhizoids well developed,  finely branched. Zoospore, discharge: Operculum present, persistent, apical or subapical, saucer shaped, diameter 4-14 µm, discharge pores one; discharge vesicle present, zoospore discharge as a mass, zoospores swarming in vesicle outside sporangium before dispersal, vesicle continuous with sporangium, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores ovoid, 2.5-3 µm in diameter, single lipid globule hyaline, flagellum 14-18 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Unknown. Ecology and Distribution: In water, parasitic on Aphanomyces laevis, causing local swelling and excessive branching of the mycelium, Karling (loc. cit., New York), US; in soil, parasitic on Aphanomyces, Karling (1967:121), NEW ZEALAND.

            “The parasite eventually completely destroyed the host. The discharged zoospores were capable of undergoing several intermittent periods of swarming if escape was not at once effected from the confining vesicle” (Karling loc. cit.).

23. CHYTRIOMYCES POCULATUS Willoughby and Townley

            Trans. Br. Mycol. Soc. 44:183, fig. 3. 1961.

            PLATE 6, figs. 169-174

            Vegetative: Thallus epibiotic. Reproductive: Sporangium ellipsoid, gibbose, or irregular, hyaline, diameter 12-22 µm, height 20-37 µm, having an extramatrical stalk; lower half of sporangial wall ornamented with up to 10 thin, overlapping cupules of wall material. Rhizoidal system: Filamentous rhizoids limited, sparsely branched. Zoospore, discharge: Operculum present, not persistent, apical, dome-shaped, diameter 5-13.5 µm, discharge pore single; discharge vesicle unknown, zoospore discharge unknown, zoospore motility unknown. Zoospore, microscopic: Zoospores spherical, 3.5 µm in diameter, hyaline, with a single, 1.5 µm diameter globule. Zoospore, ultrastructure: unknown. Resting spore: Elongate, irregular, or gibbose, thick-walled, smooth, hyaline, with 1-2 large globules. Ecology and Distribution: From soil, saprophytic on keratin bait, Willoughby and Townley (loc. cit.), on keratin, Willoughby (1962:122), UK; from soil, Dogma (1969:352, Michigan), Booth (1971a:939, Oregon), on pollen, Letcher and Powell (2001:1031; 2002:766, Virginia), from water, on pollen, Sparrow and Lange (1977:1887, Michigan), US; from soil, Booth (1969:352, British Columbia), on pollen and keratin, Booth (1971b:955, British Columbia), on pollen, Booth and Barrett (1971:363, East Arctic), Lee (2000:60, Manitoba), CANADA; from soil, Willoughby (1965:103), AUSTRALIA; Czeczuga (1994), POLAND.

            Based on actual observations of this organism (Letcher and Powell 2001, 2002), the species is emended as follows: “Chytriomyces poculatus Willoughby and Townley emend. Resting spores usually on a short extramatrical stalk 4-6 µm in length by 2-4 µm wide,  hyaline, ovoid, 12-24 µm long by 8-16 µm wide, ellipsoid, 9-21 µm long by 7-12 µm wide, surface smooth, with 4-6 overlapping cupules of wall material; containing one or two large, spherical globules 4-8µm in diameter, each globule surrounded by several minute globules; the distal end of the resting sporangium composed of a germ tube and the remnant of the zoospore cyst.”  

 

24. CHYTRIOMYCES RETICULATUS Persiel

            Arch. Mikrobiol. 36:299, fig. 8. 1960.

            PLATE 4, figs. 101-105

            Vegetative: Thallus epibiotic or extramatrical. Reproductive: Sporangium spherical, hyaline, diameter 8.5-30 µm, sessile, sporangial wall smooth. Rhizoidal system: Apophysis subspherical, filamentous rhizoids limited, sparsely branched. Zoospore, discharge: Operculum present, persistent or not persistent, apical, saucer shaped, composed of the upper half of the sporangium, first stretching as zoospores emerge, then collapsing after dehiscence, diameter 8-30 µm, discharge pore single; discharge vesicle present, zoospore discharge as a mass, zoospores swarming in vesicle outside sporangium before dispersal, vesicle continuous with sporangium, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 2.5-3.5 µm in diameter, single lipid globule hyaline, flagellum 15-18 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Spherical, 12-23 µm diameter, hyaline to light yellow, thick-walled with two membranous layers, the outer layer prismatic, the inner layer reticulate, contents granular. Ecology and Distribution: From soil, parasitic on Oomycetes (Pythium proliferum), Persiel (loc. cit.), GERMANY; Willoughby (1965:201), AUSTRALIA.

 

25. CHYTRIOMYCES RETICULOSPORUS Dogma

            Philippine J. Biol. 12:395, figs. 10-21. 1983.

            PLATE 5, figs. 126-130

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical, hyaline, diameter 9-22 µm, sessile or having an extramatrical stalk, partially collapsing and cup-like after discharge; sporangial wall smooth. Rhizoidal system: A single axis with a distal tuft of sinuous rhizoids with blunt ends. Zoospore, discharge: Operculum present, persistent or not persistent, apical or subapical, saucer shaped or collapsing after dehiscence, diameter 8-12 µm; discharge pore single; discharge vesicle absent, zoospore discharge singular, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 2.5-3.5 µm in diameter, single lipid globule hyaline, flagellum 14-17 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Spherical, 8-18 µm diameter, thick-walled, reticulate, golden brown. Ecology and Distribution: From cultivated soils, parasitic on Spizellomyces punctatus (Koch) Barr, Dogma (loc. cit.), PHILIPPINES.

 

26. CHYTRIOMYCES RHIZIDIOMYCIS Dogma

            Philippine J. Biol. 12:386, figs. 1-9. 1983.

            PLATE 2, figs. 62-65

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical or broadly pyriform, 10-15 µm tall × 8-12 µm broad, spherical or subspherical, diameter 6-14 µm, hyaline, sessile; sporangial wall smooth. Rhizoidal system: Rhizoidal axis stiff, filamentous rhizoids finely branched. Zoospore, discharge: Operculum present, persistent, apical, saucer shaped, discharge pores one or two, discharge papillae present, one or two, discharge tubes present, one or two; discharge vesicle absent, zoospore discharge as an explosive burst, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 2-2.5 µm in diameter, lipid globules many, hyaline, flagellum 12-14 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Spherical, 7-15 µm thick-walled, bullate or with warts, hyaline. Ecology and Distribution: From cultivated soils, parasitic on Rhizidiomyces bivellatus Nabel, Dogma (loc. cit.), PHILIPPINES, JAPAN.

            This species is listed in the Index of Fungi (5:282) as Chytriomyces rhizidiomycetis.

27. CHYTRIOMYCES ROTORUAENSIS Karling

            Arch. Mikrobiol. 70:269, figs. 1 P-Y; 2 A-S. 1970.

            PLATE 5, figs. 151-156

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical, ovoid,  pyriform, or variable, hyaline, diameter 10-32 µm, height 18-56 µm, polyhedral to slightly reniform and irregular or clavate when crowded; sporangial wall appendiculate or smooth. Rhizoidal system: Filamentous rhizoids well developed, sparsely branched except at extremities, branches extending for distances up to 240 µm. Zoospore, discharge: Operculum present, persistent, apical, saucer shaped, diameter 7-10 µm, discharge pores one, with a broad apical or subapical inconspicuous and hardly discernable discharge papilla; discharge vesicle present, zoospore discharge as a mass, zoospores swarming in vesicle outside sporangium before dispersal, vesicle continuous with sporangium or separating from sporangium, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores ovoid, 2.8-3.2 µm in diameter, single lipid globule hyaline. Zoospore, ultrastructure: Unknown. Resting spore: Ovoid, 7-18 µm diameter, or polyhedral when crowded, hyaline, thick-walled, smooth, contents coarsely granular; functioning as a prosporangium in germination. Ecology and Distribution: In watered mud samples, saprophytic on chitin, Karling (loc. cit.: Rotorua, Aukland Province), NEW ZEALAND.

28. CHYTRIOMYCES SPINOSUS Fay

            Mycologia 39:152, figs. 1-39. 1947.

            PLATE 3, figs. 84-88

            Vegetative: Thallus epibiotic. Reproductive: Sporangium pyriform, hyaline, diameter 11-45 µm, height 11-40 µm, sessile; sporangial wall ornamented, with simple or bifurcate spines. Rhizoidal system: Rhizoidal axis stalk-like, rarely apophysate, filamentous rhizoids well developed, branched, extending to a distance of 387 µm. Zoospore, discharge: Operculum present, persistent, apical, saucer shaped, diameter 2.3-6 µm, discharge pore single; discharge vesicle present, zoospore discharge as a mass, zoospores swarming in vesicle outside sporangium before dispersal, vesicle continuous with sporangium, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospore with a single, hyaline lipid globule. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, ovoid, 15-33 µm × 10-33.5 µm, wedge-shaped, 15 µm × 15 µm, rarely spherical, thick-walled, with simple or bifurcate spines, hyaline or slightly yellowish, with a single large globule; functions as a prosporangium in germination.  Ecology and Distribution: In soil, on cellulose, Fay (loc. cit.), from moist soil, on onion skin, Karling (1947), US.

 

29. CHYTRIOMYCES STELLATUS Karling

            Bull. Torrey Bot. Club 74:335. 1947.

            PLATE 3, figs. 66-69

            Vegetative: Thallus epibiotic. Reproductive: Sporangium irregular in shape, spherical, pyriform, or reniform, hyaline, diameter 9-50 µm, height 10-45 µm, sessile; sporangial wall ornamented, with short pegs or with simple spines. Rhizoidal system: Apophysis large, diameter up to 18 µm, spherical, fusiform, or angular; filamentous rhizoids well developed, finely branched. Zoospore, discharge: Operculum present, apical, saucer shaped, diameter 4-7 µm, discharge pore single, 1-3 or more discharge papillae present; discharge vesicle present, zoospore discharge as a mass, zoospores swarming in vesicle outside sporangium before dispersal, vesicle continuous with sporangium, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores ovoid, 3.5-5 µm in diameter, single lipid globule hyaline, flagellum 25-30 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, apophysate, spherical, 9-26 µm or ovoid, 10-14 µm × 15-22 µm, thick-walled, with simple or bifurcate spines, or stellate, sometimes wart-like, or mere undulations of the wall, hyaline, with one large or several smaller refractive globules; functions as a prosporangium in germination. Ecology and Distribution: In water and soil, on chitin, Karling (loc. cit., New York, Connecticut), US; BRAZIL.

 30. CHYTRIOMYCES SUBURCEOLATUS (Willoughby) Willoughby

            Nova Hedwigia 7: 134. 1964.

            Chytridium suburceolatum Willoughby, Trans. Brit. Mycol. Soc. 39:132, fig. 4.1956.

            PLATE 4, figs. 115-119

            Vegetative: Thallus epibiotic. Reproductive: Sporangium wide suburceolate, hyaline, height 4-22 µm, sessile; sporangial wall apiculate or smooth. Rhizoidal system: Filamentous rhizoids limited, delicate, single or finely branched. Zoospore, discharge: Operculum present, not persistent, apical, saucer shaped, discharge pores one or two; discharge vesicle absent, zoospore discharge as a mass, zoospore motility both intersporangial and extrasporangial. Zoospore, microscopic: Zoospores spherical, 2-2.5 µm in diameter, single lipid globule hyaline, flagellum 14 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical or ovoid, thick-walled, smooth, hyaline. Ecology and Distribution: From soil, parasitic on other chytrids: Rhizidium richmondense, Rhizophlyctis sp., Entophlyctis sp., Willoughby (loc. cit., 1964), UK; from soil, parasitic on Rhizophydium sphaerotheca, Kobayasi and Konno (1970:336), JAPAN.

31. CHYTRIOMYCES TABELLARIAE (C. Schröter) Canter

            Trans. Br. Mycol. Soc. 32:16, figs. 1, 2. 1949.

            Phlyctidium tabellariae C. Schröter, Neujahrblatt Naturf. Gesell. Zurich, 99: Anmerk. 3, pl. 1, fig. 48. 1897.

            PLATE 2, figs. 45-50

            Vegetative: Thallus epibiotic, sometimes interbiotic. Reproductive: Sporangium ovoid or pyriform, hyaline, diameter 6-15 µm, height 4.3-13 µm, having an extramatrical stalk; sporangial wall smooth. Rhizoidal system: Filamentous rhizoids limited, sparsely branched. Zoospore, discharge: Operculum present, persistent or not persistent, lateral, saucer shaped, diameter 4.3-8 µm, discharge pore single; discharge vesicle unknown, zoospore discharge unknown. Zoospore, microscopic: Zoospores spherical, 3 µm in diameter, single lipid globule hyaline. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, ovoid, 9.9-12 µm broad × 5.7-6 µm high, thick-walled, smooth, hyaline, containing numerous small globules; asexually formed. Ecology and Distribution: In water and mud, parasitic on Tabellaria fenestrata, Schröter (loc. cit.), SWITZERLAND; on T. floccosa, T. fenestrata, Canter (loc. cit.), UK.

32. CHYTRIOMYCES VALLESIACUS Persiel

            Arch. Mikrobiol. 36:299, fig. 11. 1960.

            PLATE 4, figs. 111-114

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical or ovoid, hyaline, diameter 10-30.5 µm, sessile; sporangial wall smooth. Rhizoidal system: Filamentous rhizoids well developed, branched. Zoospore, discharge: Operculum present, not persistent, lateral, dome shaped, collapsing after dehiscence, diameter 10-30 µm, discharge pore single; discharge vesicle present, zoospore discharge as a mass, zoospores swarming in vesicle outside sporangium before dispersal, vesicle continuous with sporangium, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 3-3.5 µm in diameter, single lipid globule hyaline, flagellum 15-20 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical, thick-walled, smooth, hyaline. Ecology and Distribution: From soil, saprophytic on pollen, Persiel (loc. cit.) AUSTRIA; from soil, saprophytic on pollen, Johnson (1971:200), ICELAND; from soil, parasitic on Rhizophydium elyensis, Willoughby (1962:125, as Chytriomyces sp. 2), UK; from soil, parasitic on C. hyalinus and R. elyensis, Willoughby (1965:104), AUSTRALIA.

            Persiel recorded vesiculate discharge for this species, whereas both Johnson (1971) and Willoughby (1962, 1965) observed spores being discharged en masse without a vesicle or zoospore swarming. Johnson (1971) also found both apophysate and nonapophysate sporangia.

33. CHYTRIOMYCES VERRUCOSUS Karling

            Bull. Torrey Bot. Club 87:327, figs. 1-18. 1960.

            PLATE 4, figs. 96-100

            Vegetative: Thallus epibiotic. Reproductive: Sporangium obpyriform, 20-46 µm high × 14-32 µm broad, subspherical, 24-42 µm, rarely spherical 18-38 µm, urceolate, subclavate, hyaline, usually sessile; sporangial wall smooth. Rhizoidal system: Filamentous rhizoids limited and sparse, branched with a bushy appearance, extending to a diameter of 22 µm. Zoospore, discharge: Operculum present, persistent, apical, subapical, or lateral, saucer shaped, diameter 8-15 µm, discharge pore single, discharge papillae one; discharge “vesicle” present only as a thin slimy layer, zoospore discharge as a mass, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 2-2.8 µm in diameter, with a single, minute, hyaline lipid globule, flagellum 9-12 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, subspherical or spherical, 14-22 µm diameter, thick-walled, tuberculate or verrucose, light brown. Ecology and Distribution: From soil, parasitic on Rhizophlyctis rosea (de Bary and Woronin) Johanson, Karling (loc. cit.:327, Michigan), US; parasitic on R. rosea, Karling (1966:57, Das-Gupta (1982:213), INDIA; parasitic on R. rosea, Karling (1968:176), Fiji, OCEANIA.

            “Chytriomyces verrucosus apparently is a parasite because it was never found growing saprophytically on cellophane, grass leaves, or other cellulosic debris. Whether or not it will attack other chytrids is unknown, as no host range studies were conducted” (Karling loc. cit.).

34. CHYTRIOMYCES WILLOUGHBYI (Willoughby) Karling

            Mycopath. et Mycol. Appl. 36:174, figs. 38-53. 1968.

            Chytridium parasiticum Willoughby, Trans. Br. Mycol. Soc. 39:132, figs. 5-7.1956.

            PLATE 6, figs. 157-162

            Vegetative: Thallus epibiotic. Reproductive: Sporangium spherical or pyriform, diameter 6-22 µm, height 8-27 µm, with a basal cyst 2-3 µm across, sessile or with an extramatrical stalk up to 10 µm long; hyaline,  sporangial wall smooth. Rhizoidal system: Apophysis minute if present, or absent; filamentous rhizoids limited, varying from an unbranched peg, up to 6 µm long × 1.8-2 µm diameter, or sparsely branched, to a more extensive system. Zoospore, discharge: Operculum present, persistent, apical, saucer shaped, discharge pore single; discharge vesicle absent, zoospore discharge as an explosive burst, zoospore motility extrasporangial only. Zoospore, microscopic: Zoospores spherical, 3.5-3.8 µm in diameter, single lipid globule hyaline, flagellum 20-24 µm long. Zoospore, ultrastructure: Unknown. Resting spore: Epibiotic, spherical, 7-17 µm diameter, thick-walled, smooth, hyaline, containing a fairly large central vacuole, contents coarsely granular and dense. Ecology and Distribution: From soil, parasitic on Rhizidium richmondense, Rhizophlyctis sp., Entophlyctis sp., and hyperparasitic on Chytriomyces suburceolatus and Septosperma rhizophydii, Willoughby (loc. cit.), UK; in soil, parasitic on the sporangia and rhizomycelia of Nowakowskiella sp., and oogonia and mycelium of Pythium sp., Karling (loc. cit.: Tokoriki, Fiji Islands; Pitcairn), OCEANIA; parasitic on Rhizophydium sp., Sparrow (1965:133, Maui), HAWAII;  parasitic on Rhizophydium stipitatum(?), Sparrow and Lange (1977:1883, Michigan), US; from soil, parasitic on Rhizophydium pollinis-pini, R. racemosum, R. elyensis, and Mucor sp., Dogma (1983:400), PHILIPPINES, JAPAN; from soil, parasitic on Rhizophlyctis sp., Johnson (1971:201), ICELAND.

 
   

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