d) Kickxellales
The 12 genera (Benjamin 1966 ; Kurihara and
Degawa 2006 )intheorderKickxellales [Fig.8.2
(21, 22)] produce septa and zygospores [Fig.8.2
(21)] similar to those of Dimargaritales except
that the septal plugs lack protuberances and do
not dissolve in KOH(Benjamin 1959 , 1966 ,
1979 ). Members ofKickxellales usually form
unispored merosporangia [Fig. 8.2(22m)]
from a phialidelike cell, the pseudophialide
[Fig.8.2(22p)], borne on a specialized fertile
structure, the sporocladium [Fig.8.2(22s)](Ben-
jamin 1959 , 1966 ). Pseudophilalides [Fig.8.2
(22p)] are not produced by species ofMycoe ̈mi-
liaandSpiromyces(Benjamin 1966 ; Kurihara
et al. 2004 ; O’Donnell et al. 1998 ), whereas the
other relatively recently described genera (Myco-
nymphaea,Ramicandelaber,Pinnaticoemansia)
produce pseudophialides (Kurihara and Degawa
2006 ; Kurihara et al. 2001 , 2004 ; Ogawa et al.
2001 ). Four sporocladial types are known in
Kickxellales (Benjamin 1966 ): two are aseptate
[Linderina,Mycoe ̈milia,Myconymphaea(occa-
sionally two-celled), Ramicandelaber, Spiro-
myces], and the remaining types have two
(Kickxella)ormanysepta(Coemansia,Dipsaco-
myces,Martensiomyces,Martensella,Pinnaticoe-
mansia, Spirodactylon). Martensella corticii
Thaxt. (Benjamin 1959 ) is a rare parasite of the
basidiomyceteCorticium radiosum(Fr.) Fr.; it is
widespread and only occurs in Canada and the
adjacent USA (Jackson and Dearden 1948 ).Spir-
omyces minutusR.K. Benj. andSpirodactylon
grow slowly in pure culture.Spiromyces aspiralis
R.K. Benj. & Benny grows and sporulates axeni-
cally on malt extract–yeast extract agar (O’Don-
nell et al. 1998 ). All other taxa of Kickxellales are
saprobic.
Most members of Kickxellales (Coemansia,
Dipsacomyces,Kickxella,Linderina,Martensio-
myces, Martensella, Mycoe ̈milia, Myconym-
phaea, Pinnaticoemansia, Ramicandelaber)
release spores in a droplet of fluid, but species
ofSpiromycesandSpirodactylonare dry-spored
at maturity (Ingold 1978 ).
A transmision electron microscope reveals
the presence of spines embedded in the spore
walls of all wet-spored Kickxellales exceptCoe-
mansia reversaTiegh. & Le Monn., and the
spine apices produce a characteristic pattern
on the merosporangial wall (Benny and Aldrich
1975 ; Young 1968 ; Zain et al. 2012 ). A saclike
organelle is attached to the base of the septum
between the merosporangium and the pseudo-
phialide and occupies the upper portion of the
latter structure. This saccate structure has been
observed in Kickxella alabastrina Coem.
[labyrinuliform organelle of Young ( 1974 )]
and Linderina pennispora Raper & Fennell
[the abscission vacuole of Benny and Aldrich
( 1975 )]. The dry-spored members of Kickxel-
lales have spines or warts on the merosporan-
gial surface (O’Donnell et al. 1998 ; Young 1968 ).
Ultrastructural observations show that the sep-
tal plug lacks protuberances and that the aerial
hyphae are adorned with noncrystalline spines
(Benny and Aldrich 1975 ; O’Donnell 1979 ;
Young 1974 ).
Members of Kickxellales can be isolated
from soil, but they also occur on dung (Benja-
min 1959 ; 1966 ).Coemansiais the only common
member of the order; many species can be
isolated from both dung and soil. Two coproph-
ilous genera, Kickxella and Spiromyces,are
rarely encountered in nature on dung (Benjamin
1966 ; O’Donnell et al. 1998 ). All remaining taxa
of Kickxellales are known from only one or two
collections, usually from soil. Soil baited with
dead, sterile arthropods added three genera
(Mycoe ̈milia,Myconymphaea, Pinnaticoeman-
sia). The fourth new genus (Ramicandelaber)
can be isolated from unbaited soil.
Kickxellais coprophilous and psychrotoler-
ant and is thus found only in localities where its
temperature requirements are met.Linderinais
a genus with two known species, and one or
both taxa can be isolated from soil collected in
subtropical or tropical parts of the world
(Chuang and Ho 2009 ; Ho et al. 2007 ; Kurihara
et al. 2008 ). Four species have been described in
Ramicandelaber, all isolated from soil (Chuang
et al. 2013 ).- Mortierellomycotina and Mortierellales
This order was described by Cavalier-Smith
( 1998 ). Members of Mortierellales (Fig.8.3)
have sporangia [Fig.8.3(23)] and sporangiola
[Fig.8.3(24)] with columellae that are absent232 G.L. Benny et al.