PLATE 1
Figs. 1-5. Chytriomyces hyalinus
Karling (Karling, 1945).
Fig. 1. Young thallus.
Fig. 2. Mature operculate, nonapophysate zoosporangium with coarse,
thick-walled rhizoidal axis.
Fig. 3. Emerging zoospores in an
exogenous discharge vesicle.
Fig. 4. Mature apophysate resting
spore.
Fig. 5. Ovoid, 3-3.5 × 5-5.5 µm
zoospore with a hyaline refractive
globule.
Figs. 6-11. Chytriomyces aureus
Karling. Figs. 6, 8-11 after Karling,
1945; fig. 7 after Karling, 1977.
Fig. 6. Young apophysate thallus.
Fig. 7. Apophysate zoosporangium
with the large primary nucleus.
Fig. 8. Mature operculate, apophysate
zoosporangium.
Fig. 9. Discharged zoosporangium.
Fig. 10. Mature resting spore.
Fig. 11. Ovoid, 3-3.5 × 5 µm zoospore
with a golden-red globule.
Figs. 12-15. Chytriomyces hyalinus v.
granulatus Karling (Karling, 1967).
Fig. 12. Young operculate, apophysate
thallus.
Fig. 13. Spherical, 5-6 µm diam.
zoospore with numerous granules.
Fig. 14. Zoospores swarming in an
exogenous discharge vesicle.
Fig. 15. Mature resting spore.
Figs. 16-21. Chytriomyces nodulatus
Haskins (Haskins, 1946).
Fig. 16. Mature, operculate apophysate
thallus.
Figs. 17, 18. Stages of dehiscence of
the zoosporangium showing operculum
and vesicle.
Fig. 19. Empty zoosporangium with
two nodules
Fig. 20. Ovoid, 3-4.5 µm zoospore with
a single refractive oil globule near point
of attachment of flagellum.
Fig. 21. Resting sporangium.
Figs. 22-28. Chytriomyces elegans
(Ingold) Dogma. Fig. 22 after Ingold,
1944; figs. 23, 27 after Canter, 1961;
figs. 24-26, 28 after Paterson, 1958.
Fig. 22. Young, immature thallus.
Fig. 23. Mature thallus.
Figs. 24-26. Stages in the vesicular
discharge of the operculate
zoosporangium.
Fig. 27. Mature resting spore;
associating bodies with apophyses.
Fig. 28. Spherical, 3.5-4.5 µm
zoospores with eccentric oil globule.
Figs. 29-35. Chytriomyces closterii
Karling (Karling, 1949)
Figs. 29, 30. Two stages of
development and maturation of
zoosporangium with sparsely branched
rhizoidal axis.
Fig. 31. Vesicle discharge of zoospores.
Fig. 32. Zoospores swarming in vesicle
prior to release.
Figs. 33. Mature resting spores.
Fig. 34. Germinating resting spore.
Fig. 35. Spherical, 2-2.5 µm diam.
zoospores.
PLATE 2
Figs. 36-40. Chytriomyces cosmaridis
Karling (Karling, 1967).
Figs. 36, 37. Developing sporangia,
each surrounded by a halo.
Fig. 38. Zoospores swarming in and
escaping from an exogenous discharge
vesicle.
Fig. 39. Resting spore.
Fig. 40. Spherical, 2-2.6 µm diam.
zoospores with a brilliantly refractive
yellow-orange globule.
Figs. 41-44. Chytriomyces
nagatoroensis Konno (Konno, 1972).
Fig. 41. Developing sporangium.
Fig. 42. Empty sporangium with nonpersistent operculum.
Fig. 43. Spherical resting spore with
rough wall.
Fig. 44. Ovoid, 3.5 µm diam.
zoospores.
Figs. 45-50. Chytriomyces tabellariae
Canter (Canter, 1949).
Fig. 45. Three stages in early
development of thallus on Tabellaria
flocculosa.
Fig. 46. Spherical, 3 µm diam. zoospore
with single refractive globule.
Fig. 47. Mature sporangium.
Fig. 48. Empty sporangia.
Fig. 49. Mature resting spore.
Fig. 50. Resting spore formed by
rounding off of protoplasm of the
sporangium.
Figs. 51-56. Chytriomyces gilgaiensis
Willoughby (Willoughby, 1965).
Fig. 51. Encysted zoospore with beaklike protrusion.
Fig. 52. Young thallus.
Fig. 53. Mature thallus with delineated
zoospores and lobed haustorium.
Fig. 54. Dehisced sporangium with
detached operculum.
Fig. 55. Dehisced sporangium with a
single residual zoospore.
Fig. 56. Pyriform, tuberculate resting
spores.
Figs. 57-61. Chytriomyces heliozoicola
Canter (Canter, 1966).
Fig. 57. Immature sporangium.
Fig. 58. Mature sporangium.
Fig. 59. Empty sporangia.
Fig. 60. Resting spores with 1-2 large
refractive globules.
Fig. 61. Spherical, 2.5-3 µm diam.
zoospores, with an anterior spherical
highly refractive globule and a posterior
less refractive oval body.
Fig. 62-65. Chytriomyces rhizidiomycis
Dogma (Dogma, 1983).
Fig. 62. Germling, and immature,
mature, and discharged sporangia on
Rhizidiomyces bivellatus.
Fig. 63. Young zoosporangium with
single (a) and two (b) discharge tubes;
zoospores escaping through discharge
tube (c); two zoospores encysted in situ
in empty zoosporangium (d).
Fig. 64. Mature resting spores.
Fig. 65. Spherical, 2-2.5 µm diam.
zoospores with a central cluster of
colorless globules.
PLATE 3
Figs. 66-69. Chytriomyces stellatus
Karling, 1947. All figures after
Karling, 1977.
Fig. 66. Sparsely spiny apophysate
zoosporangium with two exit canals
which are filled with hyaline matrix.
Fig. 67. Zoosporangium with two exit
papillae.
Fig. 68. Mature, stellate resting spores.
Fig. 69. Ovoid 3.5-4 × 4.5-5 µm
zoospore with a single hyaline
refractive globule.
Figs. 70-74. Chytriomyces
appendiculatus Karling (Karling, 1947).
Fig. 70. Maturing zoosporangium with
thickened wall and primary nucleus
within.
Fig. 71. Mature, thick-wall
zoosporangium with coarse, thickwalled rhizoidal axis; sac-shaped area
of hyaline matrix underneath the
operculum.
Fig. 72. Exogenous discharge vesicle
containing quiescent zoospores.
Fig. 73. Mature resting spore.
Fig. 74. Ovoid, 4-5 × 6-6.5 µm
zoospore with single refractive hyaline
globule.
Figs. 75-78. Chytriomyces lucidus
Karling (Karling, 1949).
Fig. 75. Mature zoosporangia filled
with large brilliant refractive globules;
rhizoidal axis thick-walled.
Fig. 76. Zoospores in an exogenous
discharge vesicle.
Fig. 77. Mature resting spores filled
with polyhedral refractive bodies.
Fig. 78. Ovoid, 5.8-6.2 µm zoospores
with large refractive globule.
Figs. 79-83. Chytriomyces fructicosus
Karling (Karling, 1949).
Fig. 79. Bi-apophysate, fully formed
sporangium with large primary nucleus.
Fig. 80. Portion of mature thallus.
Fig. 81. Discharge of zoospores into an
exogenous vesicle, from a sporangium
with two discharge tubes.
Fig. 82. Spiny hyaline resting spore.
Fig. 83. Ovoid, 3.8-4.2 × 5.5-6 µm
zoospore with hyaline, spherical
refractive globule.
Figs. 84-88. Chytriomyces spinosus
Fay (Fay, 1947).
Fig. 84. Spiny zoosporangium; hyaline
matrix filling upper ⅓ of
zoosporangium.
Fig. 85. Two stages in formation of the
vesicle and emergence of the zoospores.
Fig. 86. Mature ovoid resting spore
with large refractive globule.
Fig. 87. Germination of secondary
sporangium from resting spore.
Fig. 88. Ovoid and spherical, 3-4.5 µm
diam. zoospores with a hyaline
refractive globule.
Figs. 89-95. Chytriomyces confervae
(Wille) Batko, 1975. Figs 89-91 after
Canter, 1962; figs. 92-95 drawn from
living material by Letcher.
Fig. 89. Encysted zoospore and
germling.
Fig. 90. Immature sporangium and
halves of the split zoospore cyst.
Fig. 91. Immature sporangium with
vacuoles and two horns.
Fig. 92. Mature sporangium with
hyaline matrix below operculum.
Fig. 93. Zoospores in an exogenous
discharge vesicle.
Fig. 94. Spherical to subspherical,
hyaline resting spores, both epibiotic
and endobiotic.
Fig. 95. Spherical, 5 µm diam.
zoospores with eccentric hyaline
refractive globule.
PLATE 4
Figs. 96-100. Chytriomyces verrucosus
Karling (Karling, 1960).
Fig. 96. Sporangium of Karlingia rosea
parasitized by five thalli of
Chytriomyces verrucosus.
Fig. 97. Zoospore discharge in a thin,
slimy layer.
Fig. 98. Empty sporangium.
Fig. 99. Resting spores with verrucose
wall.
Fig. 100. Spherical, 2.2.8 µm
zoospores with small refractive globule.
Figs. 101-105. Chytriomyces
reticulatus Persiel. Figs. 101, 102A,
103-105 after Persiel, 1960; fig. 102B
after Willoughby, 1965.
Fig. 101. Immature sporangium with
small apophysis.
Fig. 102. Two empty sporangia with
collapsed opercula.
Fig. 103. Resting spore with thick,
reticulated, ridged wall.
Fig. 104. Germinated resting spore.
Fig. 105. Spherical, 2-5-3.5 µm diam.
hyaline zoospore.
Figs. 106-110. Chytriomyces
mammilifer Persiel (Persiel, 1960).
Fig. 106. Maturing zoosporangium.
Fig. 107. Partly dehisced sporangium
with large operculum.
Fig. 108. Mature resting spore with
mammiliform ornamentation.
Fig. 109. Germinating resting spore.
Fig. 110. Spherical, 3.5-4.5 µm diam.
zoospores with single refractive
globule.
Figs. 111-114. Chytriomyces
vallesiacus Persiel (Persiel, 1960).
Fig. 111. Immature and mature
sporangia on pollen grain.
Fig. 112. Empty, cupule-shaped
zoosporangium with large collapsed
operculum.
Fig. 113. Mature resting spore, with
characteristic vacuole, on pine pollen.
Fig. 114. Subspherical, 3-3.5 µm diam.
zoospore with single, refractive,
eccentric globule.
Figs. 115-119. Chytriomyces
suburceolatus (Willoughby)
Willoughby Figs. 115-117, 119 after
Willoughby, 1956; fig. 118 after
Willoughby,1965.
Fig. 115. Developmental stages of
sporangia.
Fig. 116. Two suburceolate sporangia.
Fig. 117. Empty sporangia with both
persistent and detached opercula.
Fig. 118. Resting spores with thick,
brown wall and a single large refractive
globule.
Fig. 119. Spherical, 2-2.5 µm diam.
zoospores with single oil globule.
Figs. 120-124. Chytriomyces macrooperculatus Karling (Karling, 1981).
Fig. 120. Immature multioperculate
sporangium.
Fig. 121. Emergence of zoospores
surrounded by an exogenous vesicle.
Fig. 122. Spherical, 4-5.5 µm diam.
zoospores with grayish granular content
and a minute refractive globule.
Fig. 123. Empty multioperculate
sporangium.
Fig. 124. Resting spore with smooth
reddish-brown wall and coarsely
granular content.
Fig. 125. Chytriomyces macrooperculatus v. hirsutus Karling
(Karling, 1981). Sporangium, covered
by a weft of hairs, with two rhizoidal
axes arising at the base.
PLATE 5
Figs. 126-130. Chytriomyces
reticulosporus Dogma (Dogma, 1983).
Fig. 126. Germling and immature
sporangium on Spizellomyces
punctatus.
Fig. 127. Initial, passive discharge of
zoospores.
Fig. 128. Partially collapsed, empty
sporangium with detached operculum.
Fig. 129. Mature resting spores: surface
view (left) showing reticulum, and
optical section (right) showing complex
wall layers with granular content and
small eccentric vacuole.
Fig. 130. Spherical, 2.5-3.5 µm diam.
zoospores with large, sub-basal globule.
Figs. 131-136. Chytriomyces laevis
Karling (Karling, 1987).
Fig. 131. Slightly stalked sporangium
and apophysis, causing hypertrophy of
Pythium mycelium.
Fig. 132. Sporangial dehiscence, with
operculum being pushed up by mass of
zoospores.
Fig. 133. Release of zoospores, with
operculum remaining attached to edge
of sporangium.
Fig. 134. Empty sporangium with
detached, wrinkled operculum.
Fig. 135. Spherical resting spore with
large central globule surrounded by
smaller ones.
Fig. 136. Spherical, 2.5-3 µm diam.
zoospores with conspicuous hyaline
refractive globule.
Figs. 137-140. Chytriomyces
mortierellae Persiel (Persiel, 1960).
Fig. 137. Multioperculate, nonapophysate zoosporangium on
Mortierella hygrophila.
Fig. 138. Empty sporangium.
Fig. 139. Spherical granular mature
resting spores with limited rhizoidal
system.
Fig. 140. Ovoid, 2.5 × 3.5 µm
zoospores with eccentric globule.
Figs. 141-144. Chytriomyces
multioperculatus Sparrow and Dogma
(Sparrow and Dogma, 1973).
Fig. 141. Mature sporangium with true
opercula surrounded by dehiscence
zone surmounting discharge pores.
Fig. 142. Stipitate mature sporangium.
Fig. 143. Discharged sporangium,
showing both persistent and detached
opercula.
Fig. 144. Spherical, 3.5-4 µm diam.
zoospores with single oil globule and
lunate body.
Figs. 145-150. Chytriomyces
parasiticus Karling (Karling, 1947).
Fig. 145. Apophysate young thallus,
parasitic on mycelium of Aphanomyces
laevis.
Fig. 146. Developing sporangium with
large primary nucleus.
Fig. 147. Non-apophysate, maturing
sporangium.
Fig. 148. Zoospores emerging in an
exogenous discharge vesicle.
Fig. 149. Zoospores swarming in
exogenous vesicle and escaping after
rupture of vesicle.
Fig. 150. Ovoid, 2.5-3 µm diam.
zoospores with a minute, hyaline
refractive globule.
Figs. 151-156. Chytriomyces
rotoruaensis Karling (Karling, 1970).
Fig. 151. Fully grown sporangium with
large primary nucleus, and vacuoles at
the base and apex.
Fig. 152. Maturing, oblong
sporangium.
Fig. 153. Discharge vesicle elongate,
narrow and cylindrical in the exit orifice
end enveloping a group of zoospores in
center of zoosporangium.
Fig. 154. Ovoid, 2.8-3.2 × 3-3.6 µm
zoospores with small hyaline refractive
globule.
Fig. 155. Mature resting spore.
Fig. 156. Germination of resting spore.
PLATE 6
Figs. 157-162. Chytriomyces
willoughbyi (Willoughby) Karling
(Karling, 1968).
Fig. 157. Stages in the development of
a thallus in which the incipient
sporangium is budding out of the apex
of the zoospore cyst.
Fig. 158. Stages in the development of
a thallus in which the zoospore cyst is
enlarging to form the sporangium.
Fig. 159. Spherical (2.2-3 µm diam.)
and amoeboid zoospores with single,
anterior globule.
Fig. 160. Empty sporangia.
Fig. 161. Mature resting spore with
fairly extensive branched rhizoids.
Fig. 162. Germination of resting spore.
Figs. 163-168. Chytriomyces annulatus
Dogma. Figs. 163-167, Dogma, 1969;
fig. 168, drawn from living material by
Letcher.
Fig. 163. Early and mature sporangia.
Fig. 164. Dehiscing sporangium with
hinged operculum.
Fig. 165. Empty sporangium.
Fig. 166. Spherical, 4.7-6.5 µm diam.
zoospores with single globule.
Fig. 167. Dehisced sporangium in
which young thalli have developed from
trapped zoospores.
Fig. 168. Resting spore.
Figs. 169-174. Chytriomyces poculatus
Willoughby and Townley. Figs. 169171, 173 after Willoughby and
Townley, 1961; figs. 172, 174 drawn
from living material by Letcher.
Fig. 169. Young thalli at various stages
of development.
Fig. 170. Large, mature sporangium.
Fig. 171. Dehisced sporangium with
detached operculum.
Fig. 172. Spherical (3.5 µm diam.) and
ellipsoid zoospores with single
refractive globule.
Fig. 173. Dehisced sporangium with
young thallus developing inside.
Fig. 174. Mature resting spores.
Figs. 175-179. Chytriomyces angularis
Longcore (Longcore, 1992).
Fig. 175. Germling and two gibbose,
young sporangia.
Fig. 176. Cluster of mature sporangia.
Fig. 177. Slightly ovoid, 4-5 µm diam.
zoospores with single, large lipid
globule.
Fig. 178. Dehisced sporangium with
young thallus developing from trapped
zoospore.
Fig. 179. Resistant sporangium.