Systematics and Evolution, Part A The Mycota

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Fig. 3.7 (a–x) Morphology of genera from early-
diverging clades.(a–d) Drawings ofEurychasma dick-
soniiinfectingEctocarpus. The mature thalli develop
one (a) or more (b) exit papillae. The primary aplanos-
pores are formed around the thallus periphery (a)to
form a net-like array (c) following release of biflagellate
zoospores (d). Adapted from Karling ( 1981 ) based on
original work by Sparrow ( 1934 ). (e–k) Drawings of
Haptoglossaspp. infecting rhabditid nematodes. (e)
Nematode infected with young cylindrical thalli ofH.
heterospora(e). Biflagellate zoospores (f)ofH. zoos-
pora, which encyst and form gun cells (g) in which an
inverted tube develops. From Karling ( 1981 ), after
Drechsler ( 1940 ). A nematode infected with thalli of
H. heteromorpha(h). Dimorphic aplanospores are
released that form either large uninucleate gun cells
(i) or smaller binucleate aplanopsores (j). From Glock-
ling and Beakes (2000b), with permission. Drawing of a
median section through a mature binucleate gun cell of
H. erumpens, showing inverted tube, containing needle
that punctures nematode cuticle on eversion (k). From
Glockling and Beakes (2000c), with permission (m–q).


Drawings ofOlpidiopsis saprolegniaeinfecting hyphae
and oogonia of Saprolegnia ferax. Transfer
of plasmodial thallus from cyst into hyphal cytoplasm
(m, n), which develops into a papillate thallus (o).
Spiny resting spore stages within an infected oogonium
(p) and a detail of a resting oospore and an adjacent
antheridial thallus (q). Mature thallus ofO. glenodinia-
num(r) showing direct release of zoospores from elon-
gate discharge tube, which is typical of the whole genus.
All from Karling ( 1981 ), from studies of Barrett ( 1912 ),
Coker ( 1923 ) and Johnson ( 1966 , 1972 ). (s–u) Drawings
ofHaliphthoros milfordensis. Cysts germinate to pro-
duce lobed and branching thalli (s,t). A sporangial
compartment from which zoospores are being released
via a narrow discharge tube (u). From Karling ( 1981 ),
after Sparrow ( 1974 ). (v,w) Drawings of young (v) and
mature (w) thallus of the abalone parasiteHalioticida
noduliformans,showing long hypha-like segments that
differentiate zoospores, separated by narrow spaces. (x)
Irregularly swollen thallus ofHalocrusticida parasitica
showing mature zoosporangium with slender branched
discharge tubes. From Hatai ( 2012 ), with permission

56 G.W. Beakes et al.

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