Microfungi on the Pandanaceae: Zygosporium a review of the genus and two new species

Abstract

Zygosporium pacificum sp. nov. and Z. pandanicola sp. nov. are introduced based on specimens identified on Pandanus leaves collected in the Pacific island nations of Niue and Vanuatu, and the Philippines, respectively. Both species are compared with presently accepted species and a key to the genus is provided. Specimens of Z. echinosporum, Z. gibbum, Z. minus and Z. oscheoides were also collected from members of Pandanaceae.

Full text

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207
Microfungi on the Pandanaceae: Zygosporium, a review of the
genus and two new species
Stephen R. Whitton
1*
, Eric H.C. McKenzie
1
and Kevin D. Hyde
2
1
Landcare Research, Private Bag 92170, Auckland, New Zealand
2
Centre for Research in Fungal Diversity, Department of Ecology & Biodiversity, The
University of Hong Kong, Pokfulam Road, Hong Kong SAR, PR China
Whitton, S.R., McKenzie, E.H.C. and Hyde, K.D. (2003). Microfungi on the Pandanaceae:
Zygosporium, a review of the genus and two new species. Fungal Diversity 12: 207-222.
Zygosporium pacificum sp. nov. and Z. pandanicola sp. nov. are introduced based on
specimens identified on Pandanus leaves collected in the Pacific island nations of Niue and
Vanuatu, and the Philippines, respectively. Both species are compared with presently accepted
species and a key to the genus is provided. Specimens of Z. echinosporum, Z. gibbum, Z. minus
and Z. oscheoides were also collected from members of Pandanaceae.
Key words: anamorphic fungi, Freycinetia, hyphomycetes, key, Pandanus, taxonomy.
Introduction
Zygosporium
was introduced with
Z
.
oscheoides
Mont. as the type
species. The genus is characterised by hyphomycetes possessing darkly
pigmented, incurved vesicular cells that give rise to 2-4 ampulliform
conidiogenous cells. The vesicles may be stalked or sessile, borne from the
side of a setiform conidiophore, or arise directly from the mycelium. The
conidia are aseptate, typically ellipsoid or globose, smooth or variously
ornamented and produced on ampulliform conidiogenous cells that are
typically slightly upturned (Mason, 1941; Hughes, 1951). Various authors have
reported that only one conidium is produced per conidiogenous cell (Mason,
1941; Hughes, 1951; Meredith, 1962). Meredith (1962) studied the conidial
discharge mechanism of
Z
.
oscheoides
and concluded that violent discharge
occurs, but in dry conditions only. Due to differential wall thickness, rapidly
decreasing vapour pressure causes the vesicular conidiophore to first bend
inwards, a gas phase releases built-up pressure and the vesicle springs outward,
discharging mature conidia.
When Mason (1941) reviewed the genus
Zygosporium
the vesicular
portion of the conidiophore that gives rise to the conidiogenous cells was
*
Corresponding author: S.R. Whitton; e-mail: whittons@landcareresearch.cri.nz

208
referred to as the ‘falx’, and the setiform conidiophore that give rise to the
vesicular cells as the ‘falciphore’. Various authors since have adopted these
terms (e.g. Hughes, 1951; Barron, 1968; Pirozynski, 1972; Thakur and Udipi,
1976; Subramanian and Bhat, 1987). In most previous assessments, the genus
is described as not having true setae, the setiform structures being described as
conidiophores or setiform conidiophores. However,
Z
.
deightonii
M.B. Ellis
(Ellis, 1976) and
Z
.
echinosporum
Bunting & E.W. Mason (Hughes, 1951)
both produce setiform structures that do not produce vesicles and are referred
to here as true setae. Where species produce vesicles from the side of the
setiform structures (e.g.
Z
.
geminatum
S. Hughes,
Z
.
majus
Piroz.,
Z
.
minus
S.
Hughes and
Z
.
oscheoides
Mont.), these structures are referred to as setiform
conidiophores. To differentiate between the setiform and the vesicular part of
the structure they are referred to as setiform conidiophores and vesicular
conidiophores in the following descriptions. This more or less follows the
terminology utilised by Ellis (1971, 1976).
Several taxa treated in
Zygosporium
require discussion.
Zygosporium
blighiae
Gonz. Frag. & Cif. and
Z
.
paraense
Vincens were both treated as
synonyms of
Z
.
oscheoides
by Mason (1941) and Hughes (1951), and this
treatment is continued in the current manuscript. Mason (1941) treated
Z
.
mycophilum
(Vuill.) Sacc. as a synonym of
Z
.
parasiticum
(Grove) Bunting &
E.W. Mason as the vesicular conidiophores of both species are borne directly
on the superficial mycelium and the differences in conidial dimensions were
not considered significant enough to warrant specific recognition. Hughes
(1951) also discussed the synonymy of
Z
.
mycophilum
, but concluded that due
to dimensional differences of various morphological characters, especially
those of the conidia, it was better to consider the two species as separate.
Hughes (1958) reviewed many type specimens of hyphomycetes housed in
European herbaria including
Clasterosporium
gibbum
Sacc. M. Rousseau &
Bommer, which he transferred to
Zygosporium
. In addition he placed
Z
.
parasiticum
into synonymy with
Z
.
gibbum
(Sacc., Rousseau & Bommer) S.J.
Hughes, as he considered the types of both species to be conspecific. The type
specimen of
Z
.
gibbum
has nomenclatural priority over
Z
.
parasiticum
.
Urobasidium
rostratum
Giesenh. was transferred to
Zygosporium
by Bunting
and Mason (in Mason, 1941). This species, known only from the description
and figure of its type collection, is similar in morphology to
Z
.
gibbum
. The
major differences being slightly broader conidia (6-8 µm diam.) and the
vesicular conidiophores are reported to produce only two conidiogenous cells.
As
Z
.
gibbum
produces 2-3 conidiogenous cells per vesicular conidiophore, the
difference in conidial size is small, and no new material has been collected

Fungal Diversity
209
since its introduction,
Z
.
rostratum
(Giesenh.) Bunting & E.W. Mason is
regarded here as inadequately known to treat.
This work originates from an ongoing study of the saprobic microfungi
that inhabit members of the monocotyledon family
Pandanaceae
(McKenzie,
1995; McKenzie and Hyde, 1996; Hyde, 1997; Whitton
et
al
., 1999, 2000). No
species of
Zygosporium
has been described from members of the
Pandanaceae
(McKenzie and Hyde, 1996). However,
Z
.
oscheoides
has been reported from
Pandanus
odoratissimus
(Hughes, 1951) and
P
.
tectorius
(Matsushima, 1975).
In this paper,
Zygosporium
pacificum
found on unidentified species of
Pandanus
in Niue and Vanuatu and
Z
.
pandanicola
found on
Pandanus
simplex
in the Philippines are described as new and compared with currently
accepted species. Brief descriptions are given for four other species of
Zygosporium
found on decaying leaves of
Freycinetia
or
Pandanus
. A key to
Zygosporium
species is provided, together with a synopsis of the genus (Table
1).
Key to species of Zygosporium
Measurements in some cases refer to composite dimensions from
additional published specimens. Some measurements have been rounded up or
down to nearest 0.5 µm as appropriate.
1. Vesicular conidiophores always or sometimes borne directly on superficial mycelium ........2
1. Vesicular conidiophores always produced from the side of the setiform conidiophores .......7
2. With setae...............................................................................................................................3
2. Without setae..........................................................................................................................4
3. Vesicular conidiophores with 3 conidiogenous cells and a short, sterile apical cell, stalk
cells up to 45 µm long; interspersed with sterile setae, apex hyaline and swollen (6-8 µm
wide); conidia ellipsoid, hyaline to pale brown, smooth or verruculose, 9-15 × 6-9 µm .........
............................................................................................................................. Z. deightonii
3. Vesicular conidiophores with 3-4 conidiogenous cells, no sterile apical cell, either borne on
setiform conidiophores or arising directly from mycelium; setae sterile or with 1-2 vesicular
conidiophores, apex hyaline and swollen (5-7 µm wide); conidia spherical, hyaline,
verrucose, 6-11 µm diam...............................................................................Z. echinosporum
4. Vesicular conidiophores in stacked chains of 1-6, each with 2 conidiogenous cells, and a
cylindrical sterile cell at the apex (12-36 µm long); conidia ovoid, hyaline, smooth, 5-10 ×
3-5 µm .....................................................................................................................Z. masonii
4. Vesicular conidiophores not in stacked chains.......................................................................5
5. Vesicular conidiophores with 2-3 conidiogenous cells and a sterile apical cell (7-11 µm
long); conidia ovoid, hyaline, minutely verruculose, 6-11 × 4-7 µm ...............Z. mycophilum
5. Conidia spherical....................................................................................................................6

210
6. Vesicular conidiophores with 2-3 conidiogenous cells and a sterile apical cell (5-8 µm
long); conidia hyaline, smooth to minutely verruculose, 4-8 µm diam. .................. Z. gibbum
6. Vesicular conidiophores with 3-4 conidiogenous cells; conidia hyaline, smooth, 8.5-10 µm
diam.................................................................................................................. Z. tonellianum
7. Conidia spherical ................................................................................................................... 8
7. Conidia not spherical........................................................................................................... 12
8. Conidia echinulate, spines up to 3.5 µm long, subhyaline to pale brown, 12.5-16.5 µm
diam.; setiform conidiophores 81-98 µm long, apical cell hyaline to pale-brown, tapering,
sparsely roughened .........................................................................................Z. tuberculatum
8. Conidia not echinulate ........................................................................................................... 9
9. Conidia tuberculate, raised areas flattened and irregular in shape, brown, 11-14.5 µm diam.;
setiform conidiophores 60-100 µm long, apical cell subhyaline, smooth, narrowly clavate
(2-2.5 µm wide)............................................................................................... Z. pandanicola
9. Conidia not tuberculate........................................................................................................ 10
10. Conidia verrucose or coarsely roughened............................................................................ 11
10. Conidia smooth, hyaline, 7-10 µm diam.; setiform conidiophores 20-70 µm long, apical cell
hyaline, smooth, swollen (3-4 µm wide) ............................................................ Z. chartarum
11. Conidia coarsely roughened, pale brown, 13-18 µm diam.; setiform conidiophores 75-100
µm long, apical cell subhyaline, smooth, tapering or narrowly clavate (1.5-2 µm wide)........
....................................................................................................................................Z. majus
11. Conidia verrucose, hyaline to pale-brown, 5.5-10 µm diam.; setiform conidiophores 35-50
µm long, apical cell subhyaline, smooth, narrowly clavate (1.5 µm wide) ................Z. minus
12. Conidia tuberculate, raised areas flattened.......................................................................... 13
12. Conidia smooth or minutely verruculose ............................................................................ 14
13. Conidia ellipsoid, pale brown to brown, 20-30 × 8-11 µm; setiform conidiophores 65-110
µm long, apical cell subhyaline, sparsely echinulate, narrowly clavate (2-3.5 µm wide) .......
........................................................................................................................... Z. geminatum
13. Conidia ellipsoid, pale brown, 11-16 × 6.5-7.5 µm; setiform conidiophores 53-61 µm long,
apical cell subhyaline, smooth, narrowly clavate (2-2.5 µm wide) ..................... Z. pacificum
14. Conidia ellipsoid, hyaline to pale-brown, smooth to minutely verruculose, 7-12.5 × 4-9 µm;
setiform conidiophores 30-60 µm long, apical cell subhyaline, smooth, acute or narrowly
clavate.................................................................................................................Z. oscheoides
14. Conidia ovoid, hyaline, smooth, 6.5-13.5 × 5-6 µm; setiform conidiophores up to 45 µm
long, apical cell hyaline, smooth and narrowly clavate or obtuse, erect lateral branch 46-75
µm long also produced ....................................................................................Z. verticillatum
Taxonomy
Zygosporium Mont., Annales des Sciences Naturelles, Botanique, Séries 2, 17:
120 (1842).
= Pimina Grove, Journal of Botany, London 26: 206 (1888).
= Urobasidium Giesenh., Flora, Jena 76: 139 (1893).

Fungal Diversity
211
= Urophiala Vuill., Bulletin des Séances de la Société des Sciences de Nancy 11: 169
(1910).
Type species: Zygosporium oscheoides Mont., Annales des Sciences Naturelles,
Botanique, Séries 2, 17: 120 (1842).
Zygosporium echinosporum Bunting & E.W. Mason, Mycological Papers 5:
135 (1941).
Setae
and
setiform
conidiophores
2-4-septate, spherical head 4-7 µm
wide, overall length 51-140 µm, 2-3 µm wide towards the base.
Conidiophore
stalk cell/s 12-40 × 2-3 µm, vesicular cell 9-14 × 5-6 µm.
Conidiogenous
cells
3-4 per vesicular cell, 6-10 × 3.5-5.5 µm.
Conidia
6-10.5 µm diam.
Habitat: Known to inhabit decaying leaves of Areca catechu, Artocarpus sp., Cocos
nucifera, Cola lateritia, Cordia sp., Desplatzia lutea, Ficus sp., Glycine max, Hyphaene
thebaica, Laurus nobilis, Livistona chinensis, Millettia sp., Pancovia bijuga, Pandanus
simplex, Phormium tenax, Swietenia macrophylla, Theobroma sp. and unidentified palm
petioles, also isolated from cheese and air.
Known distribution: Brazil (Gusmão et al., 2001), Ghana (Hughes, 1951, 1952), Hawaii
(Wang and Baker, 1967), Hong Kong (Yanna et al., 2001), India (UKNCC, 2002), Malaysia
(UKNCC, 2002), Nigeria (Ellis, 1971), Peru (Matsushima, 1993), Philippines (current
specimen), Sierra Leone (Ellis, 1971), Taiwan (Matsushima, 1980), Trinidad (Ellis, 1971), UK
(Sutton and Pirozynski, 1963; Kirk, 1983).
Material examined: PHILIPPINES, Luzon Island, Quezon Region, Laguna, Baranggay
Bakas Luisiana, on decaying leaves of Pandanus simplex, 22 October 1996, S.R. Whitton
[HKU(M) 12908, 12916].
Notes
:
Zygosporium
echinosporum
is characterised by vesicular
conidiophores being borne from the side of setiform conidiophores or directly
from the superficial mycelium. The conidia are spherical, hyaline or pale,
verruculose and 6-9 µm diam. (Hughes, 1951; Ellis, 1971; Kirk, 1983). The
current specimen agrees with the description for
Z
.
echinosporum
given by
Hughes (1951) with little observable variation; the slightly larger conidial
diam. is thought to represent natural variation.
Zygosporium gibbum (Sacc., M. Rousseau & E. Bommer) S. Hughes,
Canadian Journal of Botany 36: 825 (1958).
≡ Clasterosporium gibbum Sacc., M. Rousseau & E. Bommer, in Saccardo, Atti della
Reale Istituto Scienze, Lettere ed Arti, VI, 2: 455 (1884).
= Pimina parasitica Grove, Journal of Botany, London 26: 206 (1888).
≡ Urophiala parasitica (Grove) A.L. Sm., Transactions of the British Mycological
Society 6: 296 (1920).
≡ Zygosporium parasiticum (Grove) Bunting & E.W. Mason, Mycological Papers 5:
137 (1941).
Conidiophores
1-3 stalk cells, 6-17 × 3.5-4.5 µm, vesicular cell 11-14 ×
6.5-8 µm, apical cylindrical appendage 4.5-8 × 3-4 µm.
Conidiogenous
cells
3
per vesicle, 6-8 × 3.5-4.5 µm.
Conidia
5-6.5 µm diam.

212
Habitat: On decaying plant parts of Acacia confusa, A. koa, A. koa var. hawaiiensis,
Artocarpus sp., Avicennia officinalis, Bischofia javanica, Borassus sp., Camelia japonica,
Ceriops decandra, Cola sp., Culcasia sp., Dacrydium cupressinum, Dioscorea sp., Elaeis sp.,
Eucalyptus saligna, E. tereticornis, Euonymus sp., Ficus sp., Hydnocarpus sp., Hyphane sp.,
Ilex aquifolium, Juncus roemerianus, Landolphia sp., Laurus nobilis, Litsea sp., Magnolia
obovata, Mangifera indica, Matayba domingensis, Metrosideros collina, M. collina subsp.
polymorpha, Metroxylon sagu, Musa sp., Nephelium sp., Ochthocosmus sp., Pandanus sp.,
Passiflora sp., Phormium tenax, Phyllostachys sp., Podocarpus sp., P. macrophyllus,
Polypodium sp., Pteridium aquilinum, Quercus sp., Quercus phillyraeoides, Rhododendron
ponticum, Rhopalostylis sapida, Sequoia sempervirens, Smilax sp., and unidentified palm
petiole.
Known distribution: Costa Rica (Ellis, 1971), Cuba (Holubová-Jechová and Mercado
Sierra, 1986), Hawaii (Baker et al., 1979; Raabe et al., 1981), Hong Kong (Ellis, 1971), Ghana
(Ellis, 1971), India (Vittal and Dorai, 1994; Sarma and Vittal, 2001; UKNCC, 2002), Japan
(Matsushima, 1975; Hatano, 2002), New Zealand (Hughes, 1978), Pakistan (Ellis, 1971),
Papua New Guinea (Shaw, 1984), Sabah (Ellis, 1971), Sierra Leone (Ellis, 1971), Solomon
Islands (Ellis, 1971), Taiwan (Matsushima, 1980), UK (Kirk, 1981, 1983), USA (Sutton, 1978;
Miller, 1991), Vietnam (current specimen).
Material examined: VIETNAM, Nah Trang, on decaying leaves of Pandanus sp., 28
May 1997, J.G. Wright [HKU(M) 12910].
Notes
:
Zygosporium
gibbum
is characterised by stalked vesicular
conidiophores that are produced directly from the superficial mycelium. No
setiform conidiophores or setae are produced. The conidia are spherical,
hyaline, smooth to finely verruculose, and 4.5-6 µm diam. (Ellis, 1971). The
only observable difference from the description given by Ellis (1971) for
Z
.
gibbum
is the slightly wider conidia, which is interpreted as natural variation.
Zygosporium minus S. Hughes, Mycological Papers 44: 6 (1951).
Setiform
conidiophores
3-5-septate, 30-140 µm long, 2-4 µm wide
towards the base, 1-1.5 µm wide at the apical septa.
Vesicular
conidiophores
1
stalk cell, 3-7 × 2.5-5.5 µm, vesicular cell 9-16 × 4.5-9 µm.
Conidiogenous
cells
2 per vesicle, 4-10 × 4-5.5 µm.
Conidia
5.5-10 µm diam.
Habitat: Known to inhabit decaying leaves of Artocarpus nobilis, Cocos sp., Cola
lateritia, Corynocarpus laevigatus, Crinum sp., Dracaena sp., Elaeis sp., Ficus sp., Hibiscus
sp., Livistona chinensis, Musa sp., Pandanus sp., P. copelandii, P. simplex, P. tectorius,
Panicum sp., Phormium tenax, Polyalthia sp., Rhopalostylis sapida, Solanum aculeatum,
Tabebuia serratifolia, T. shaferi, Tournefortia hirsutissima and various unidentified leaves.
Known distribution: Cuba (Ellis, 1971), Fiji (current specimen), Ghana (Hughes, 1951),
Hong Kong (Yanna et al., 2001; current specimen), India (Ellis, 1971), New Zealand (Hughes,
1978; McKenzie, 1991), Peru (Matsushima, 1993), Philippines (current specimens), Sierra
Leone (Ellis, 1971), Tanzania (Ellis, 1971), Venezuela (Ellis, 1971), Zambia (Ellis, 1971).
Material examined: FIJI, Viti Levu Island, Naduruvatu, on decaying leaves of
Pandanus sp., 15 February 1996, E.H.C. McKenzie (PDD 65787). HONG KONG, Lantau
Island, north end of Discovery Bay, on decaying leaves of Pandanus tectorius, 6 August 1995,
S.R. Whitton [HKU(M) 12915]. PHILIPPINES, Luzon Island, Quezon Region, Baranggay
Maragondon Real, on decaying leaves of P. copelandii, 21 October 1996, S.R. Whitton

Fungal Diversity
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[HKU(M) 12911]; Luzon Island, Quezon Region, Laguna, Baranggay Bakas Luisiana, on
decaying leaves of P. simplex, 22 October 1996, S.R. Whitton [HKU(M) 12912].
Notes
:
Zygosporium
minus
is characterised by setiform conidiophores,
which are often slightly swollen and pale at the apex, and produce vesicular
conidiophores typically just above the basal septum. The vesicular
conidiophores give rise to two conidiogenous cells that in turn produce
spherical, hyaline to pale brown, verruculose, 6-9 µm diam. conidia (Ellis,
1971). Morphologically,
Z
.
majus
is similar to
Z
.
minus
, but has larger conidia
(13-18 µm diam.) and is reported to be a plant pathogen (Pirozynski, 1972;
Ellis, 1976). The current specimens agree with the descriptions of
Z
.
minus
, the
small variation in conidial size is thought to represent natural variation.
Zygosporium oscheoides Mont., Annales des Sciences Naturelles, Séries 2, 77:
121 (1842).
= Cladotrichum passiflorae Pim, Gardener’s Chronicle 24: 724 (1885).
= Zygosporium paraense Vincens, Bulletin de la Société de Pathologie Végétale France
2: 19 (1915).
= Zygosporium blighiae Gonz. Frag. & Cif., Boletin de la Sociedad Española de
Historia de la Natural 27: 332 (1927).
Setiform
conidiophores
3-4-septate, 41-65 µm long, 2-3.5 µm wide
towards the base, 1-1.5 µm wide at the apical septa.
Vesicular
conidiophores
1
stalk cell, 4.5-6 × 3-5 µm, vesicular cell 10-13 × 6-7.5 µm.
Conidiogenous
cells
2 per vesicle, 5-6 × 4.5-6 µm.
Conidia
8-13.5 × 6-8 µm.
Habitat: Known to inhabit decaying leaves of Agathis alba, Ananas comosus, Annona
muricata, Anthurium sp., Areca catechu, A. lutescens, Arenga engleri, Artocarpus altilis, A.
communis, A. incisa, A. integrifolia, A. nobilis, Bauhinia tomentosa, Borassus aethiopum,
Caladium bicolor, Calotropis procera, Carica papaya, Carludovica insignis, Carpodinus
hirsuta, Cecropia sp., Chamaedora sp., Citrus sinensis, Cocos nucifera, Cola lateritia, Crinum
sp., Culcasia scandens, Cupania glabra, Desmodium sp., Desplatzia lutea, Dichapetalum
flexuosum, Drypetes sp., Duranta repens, Elaeis guineensis, Encephalortos barteri, Erythrina
senegalensis, Eucalyptus sp., Fagara xanthoxyloides, Ficus sp., F. elastica, Freycinetia sp., F.
wilderi, Heliconia brasiliensis, Hevea brasiliensis, Hugonia sp., Livistona sp., L. chinensis,
Mallotus oppositifolius, Malpighia punicifolia, Miscanthus sinensis, Musa acuminata, M.
paradisiaca, M. sapientum, Nephthytis picturata, Nolina rucurvata, Ochthocosmus africanus,
Pancovia bijuga, Pandanus sp., P. odoratissimus, P. tectorius, P. tectorius var. liukiuensis, P.
wilderi, Passiflora suberosa, Petiveria alliacea, Phoenix reclinata, Phormium sp., P. tenax,
Phyla strigillosa, Phyllanthus discoideus, Pisonia rotundata, Pithecellobium dulce,
Podocarpus sp., Polianthes tuberosa, Polypodium sp., Pothos aureus, Rhopalostylis sapida,
Ribes nigrum, Roystonea regia, Saccharum officinarum, Setaria chevalieri, Theobroma cacao,
Thunbergia sp., Vanilla planifolia, Yucca gloriosa and unidentified leaves, also isolated from
air.
Known distribution: Brazil (Ellis, 1971; Abarca and Mercado Sierra, 1998), Congo
(Ellis, 1971), Cook Islands (current specimen), Cuba (Hughes, 1951; Holubová-Jechová and
Mercado Sierra, 1986), Ghana (Hughes, 1951), Guernsey (Ellis, 1971), Hawaii (Raabe et al.,
1981), Hong Kong (Photita et al., 2001; Yanna et al., 2001; current specimen), India (Ellis,

214
1971), Jamaica (Ellis, 1971), Japan (Matsushima, 1975), Malaysia (Peregrine and Ahmad,
1982), Mauritius (Hughes, 1951), Mexico (Mercado Sierra and Heredia, 1994), New Zealand
(Hughes, 1978), Nigeria (UKNCC, 2002), Panama (Goos and Pirozynski, 1975), Papua New
Guinea (Matsushima, 1971; Shaw, 1984), Peru (Matsushima, 1993), Philippines (Teodoro,
1937), Samoa (Ellis, 1971; current specimen), Seychelles (Hughes, 1951), Sierra Leone
(Hughes, 1951), Sri Lanka (Ellis, 1971), St Helena (Hughes, 1951), Tanzania (Matsushima,
1980), Togo (Hughes, 1951), Uganda (Hughes, 1951), UK (Dennis, 1986), USA (Hughes,
1951; Morgan-Jones, 1974; Sutton, 1978), Vanuatu (Ellis, 1971), Venezuela (Ellis, 1971),
Vietnam (current specimen).
Material examined: COOK ISLANDS, Rarotonga, on decaying leaves of Freycinetia
wilderi, August 1987, R.A. Fullerton (PDD 49589). HONG KONG, New Territories, Sai Kung
Peninsula, on decaying leaves of Pandanus tectorius, 1 April 1994, E.H.C. McKenzie and K.D.
Hyde (PDD 63331). SAMOA, on decaying leaves of Freycinetia sp., June 1987, P.C. Gardner
(PDD 45629). VIETNAM, Nah Trang, on decaying leaves of Pandanus sp., 28 May 1997, J.G.
Wright [HKU(M) 12913].
Notes
:
Zygosporium
oscheoides
, which is the commonest species of
Zygosporium
(Ellis, 1971), is characterised by setiform conidiophores that are
slightly swollen and pale at the apex. These give rise to a single vesicular
conidiophore just above the basal septum. The vesicular conidiophore in turn
gives rise to two pale conidiogenous cells that produce ellipsoid, hyaline to
pale brown, smooth to minutely verruculose, 7-12 × 4-7 µm conidia (Hughes,
1951; Ellis, 1971). The current specimens show very little variation from the
description given by Hughes (1951) for
Z
.
oscheoides
; the slight difference in
conidial size is interpreted as natural variation.
Zygosporium pacificum Whitton, McKenzie & K.D. Hyde, sp. nov.
(Figs. 1-10)
Etymology: pacificum, refers to the known distribution, Niue and Vanuatu, South
Pacific.
Coloniae effusae. Mycelium partim superficiale, partim immersum, partim in substrato
superficiale cylindricae, brunneae, laevia, septatis, ramosa, 2-3 µm diam. Setiforma
conidiophora 53-61 µm longa, 3.5-5 µm lata ad basim, 1-2 µm lata ad apicem septata, erecta,
plerumque recta, curvus vel flexuosa, laevia vel irregularis verrucosa, 3-septata, brunnae vel
atrobrunnea, cellula apicem pallidae brunnea vel hyalinea, crassitunicata, cellula apicalis parce
inflata (2-2.5 µm) et obtuse. Vesicula conidiophora lateralem ad suprabasalis, complectens de
tres cellula; cellula ad stipitis, cylindrica, brunneae vel atrobrunnea, crassitunicata, laevia;
cellula vesicula atrobrunnea vel atra, crassitunicata, laevia, inflata, introrsus curvati, 19-28 × 8-
12.5 µm. Cellulae conidiogenae enatus vel cellula vesiculae, monoblasticae, discretae, inflatae,
ampulliformae vel globosa, introrsus curvatae, laeviae vel parce verrucosa, pallidiae brunneae,
apice obtusae, 6-8 µm diam. Conidia 11-16 × 6.5-7.5 µm, solitaria, sicca, ellipsoidea,
crassitunicata, aseptata, pallidea brunnea, rotundata ad extremum, crassus verrucosa.
Colonies
effuse to compact, forming a thin, irregular shaped patch on the
substrate surface, black.
Mycelium
superficial and immersed, superficial
hyphae cylindrical, brown fading to pale brown away from the base of the
setae, smooth, septate, branched, 2-3 µm diam.
Stroma
none.
Hyphopodia

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215
Figs. 1-10. Zygosporium pacificum (from holotype). 1. Colony on substratum. 2-7. Conidia.
Note the tuberculate ornamentation. 8-10. Setiform conidiophores with attached vesicular
conidiophores. Note the superficial mycelium in Fig. 8. Bars: 1 = 500 µm; 2-10 = 10 µm.
absent.
Setiform
conidiophores
53-61 µm long, 3.5-5 µm wide towards the
base, 1-2 µm wide at the apical septa, erect, typically straight, sometimes
curved or flexuous, tapered from the base towards the apex, smooth or with
irregular granules, typically 3-septate, brown or dark brown, apical cell paler,
thickened walls and septa, especially towards the base, apical cell thin walled,
slightly enlarged (2-2.5 µm) and obtuse, first cell giving rise to a single
vesicular conidiophore, basal cell concolourous with the lower parts of the
setae, and branching in two directions, becoming part of the mycelium and
connecting the conidiophores with each other.
Vesicular
conidiophores

216
typically arising at the base of the first cell of the setiform conidiophore,
consisting of three cell types; stalk cell cylindrical, brown to darkish brown,
thick walled, smooth, dark brown to black, thick walled, smooth; vesicular cell
swollen, upwardly curved, 19-28 × 8-12.5 µm; 2 conidiogenous cells; inner
curvature of the vesicular cell paler than the rest of the cell.
Conidiogenous
cells
monoblastic, discrete, determinate, swollen, ampulliform to almost
globose, upwardly curved, smooth or minutely verrucose, pale brown to almost
hyaline, apex obtuse, 6-8 µm diam.
Conidia
11-16 × 6.5-7.5 µm, solitary, dry,
elliptical, thick walled, aseptate, pale brown, both ends rounded, coarsely
verrucose with raised and flattened ornamentation.
Habitat: Known to inhabit decaying leaves of Pandanus sp.
Known distribution: Niue, Vanuatu.
Material examined: VANUATU, Espiritu Santo Island, South Santo, on decaying
leaves of Pandanus sp., 31 October 1996, E.H.C. McKenzie [HKU(M) 12914, holotype
designated here]. NIUE, on decaying leaves of Pandanus sp., 10 October 2000, E.H.C.
McKenzie (PDD 72254).
Notes
: The conidiophore morphology of
Z
.
pacificum
is similar to that of
Z
.
majus
,
Z
.
minus
and
Z
.
pandanicola
, but it differs in regard to conidial
morphology (Ellis, 1971, 1976). The conidia of
Z
.
oscheoides
are similar to
Z
.
pacificum
, but are smaller (7-12 × 4-7 µm) and with different ornamentation
morphology. In addition, the vesicular conidiophores of
Z
.
oscheoides
are
borne directly on the superficial hyphae as well as on the setiform
conidiophores (Ellis, 1971), a situation that has not been observed in
Z
.
pacificum
. The conidia of both
Z
.
minus
and
Z
.
majus
are spherical (Ellis,
1971, 1976; Pirozynski, 1972).
Zygosporium pandanicola Whitton, McKenzie & K.D. Hyde, sp. nov.
(Figs. 11-23)
Etymology: pandanicola, refers to the type substrate, Pandanus.
Coloniae effusae. Mycelium plerumque superficiale, partim in substrato superficiale,
cylindricae, pallidae brunneae, laevia, septatis, ramosa, 2.5-4 µm diam. Setiforma
conidiophora 60-100 µm longa, 4-5.5 µm lata ad basim, 1-1.5 µm lata ad apicem septata,
erecta, recta, curvus vel flexuosa, laevia, 3-4-septata, brunnae, crassitunicata, cellula apicalis
parce inflata (2-2.5 µm) et obtuse. Vesicula conidiophora lateralem ad suprabasalis,
complectens de tres cellula; cellula ad stipitis, cylindrica, brunneae, crassitunicata, laevia, 5-8 ×
4.5-5 µm; cellula vesicula brunneae vel atrobrunnea, crassitunicata, laevia, inflata, introrsus
curvati, 15.5-16 × 8.5-9 µm. Cellulae conidiogenae enatus vel cellula vesiculae,
monoblasticae, discretae, inflatae, ampulliformae, introrsus curvatae, laeviae, pallidiae
brunneae, apice obtusae, 6-11 × 6.5-9 µm. Conidia 11-14.5 µm diam., solitaria, sicca, spherica
vel late ellipsoidea, aseptata, brunnea, crassitunicata, grosse verrucosa.
Colonies
effuse to compact, forming a thin, irregular-shaped patch on the
substrate surface, black.
Mycelium
mostly superficial, cylindrical, pale brown,
smooth, septate, branched, 2.5-4 µm diam., slightly thickened walls.
Stroma

Fungal Diversity
217
Figs. 11-23. Zygosporium pandanicola (from holotype). 11. Colony on substratum. 12-17.
Conidia. 18, 19. Vesicular conidiophores showing the two conidiogenous cells. 20-23. Setiform
conidiophores with attached vesicular conidiophores. Note the superficial hyphae in Fig. 21.
Bars: 11 = 500 µm; 12-23 = 10 µm.
none.
Hyphopodia
absent.
Setiform
conidiophores
60-100 µm long, 4-5.5 µm
wide towards the base, 1-1.5 µm wide at the apical septa, erect, straight, curved
or flexuous, tapered from the base, narrowing towards the apex, smooth, 3-4-
septate, brown except for the pale apical cell, thickened walls and septa, apical

218
Table 1. Synopsis of Zygosporium.
Species Conidia Setiform conidiophores
(or setae)
Vesicular conidiophores
Morphology Size
(µm
)
Morphology Size
(
µm
)
Morphology Size
(
µm
)
Conidiogenous
cells per VC
Z. chartarum
Spherical, smooth,
hyaline
7-10 Dark brown below, hyaline,
swollen (3-4
µm
) and
smooth at the apex
20-70 ×
3-3.5
Dark brown, arising from SC, 1
per SC
4-5 ×
8-12
2
Z. deightonii
Ellipsoid, smooth or
verruculose, hyaline to
pale-brown
9-15 ×
6-9
Dark brown below, hyaline,
swollen (6-8 µm
) and
smooth at the apex
60-130 ×
2-3
Dark brown, arising from the
mycelium, short, pale-brown,
sterile cell at apex
up to 45 ×
7-9 wide
3
Z. echinosporum
Spherical (rarely
ellipsoid),
verruculose, hyaline to
yellowish
6-11 Dark brown below, hyaline,
swollen (5-7
µm
) and
smooth at the apex
50-300 ×
2-4
Dark brown, arising from SC or
mycelium, 1-5 per SC
9-15 ×
6.5-10
3-4
Z. geminatum
Ellipsoid, tuberculate,
raised areas flattened,
pale brown to brown
20-30 ×
8-11
Dark brown below, hyaline,
clavate and sparsely
echinulate at the apex
65-110 ×
3.5-5
Dark brown, arising from SC, 1
per SC
12-15 ×
6-8
2
Z. gibbum
Spherical, smooth to
minutely verruculose,
hyaline
4-8 Absent, 1 cylindrical stalk
cell
NA Dark brown, arising directly from
mycelium, pale-brown sterile cell
at apex
10-15 ×
7-9
2-3
Z. majus
Spherical, coarsely
roughened, pale-
brown, basal scar
13-18 Dark brown below, hyaline,
clavate and smooth at the
apex
75-100 ×
3.5-5
Dark brown, arising from SC, 1
per SC
13-20 ×
7-12
2
Z. masonii
Ovoid, smooth,
hyaline
5-10 ×
3-5
Absent, 1-6 cylindrical stalk
cells
Stalk cells
7-50 ×
2-2.5
Dark brown, arising directly from
mycelium, often in a chain of 2-6
VC, pale sterile cell at apex (12-
36 × 1-2.5
µm
)
6-12 ×
4-6
2
Z. minus
Spherical, minutely
verruculose, hyaline to
pale-brown
5.5-10
Dark brown below, hyaline,
clavate and smooth at the
apex
35-50 ×
2-3
Dark brown, arising from SC, 1
per SC
8-12 ×
3.5-8
2
Measurements in some cases refer to composite dimensions from additional published specimens. Some measurements have been rounded
up or down to nearest 0.5 µm as appropriate. SC = setiform conidiophore, VC = vesicular conidiophores.

Fungal Diversity
219
Table 1. (continued).
Species Conidia Setiform conidiophores
(or setae)
Vesicular conidiophores
Morphology Size
(µm
)
Morphology Size
(
µm
)
Morphology Size
(
µm
)
Conidiogenous
cells per VC
Z. mycophilum
Ovoid, minutely
verruculose, hyaline,
minute basal scar
6-11 ×
4-7
Absent, 1-6 cylindrical stalk
cells
Stalk cells
6-54 ×
2-3
Dark brown, arising directly from
mycelium, rarely in a chain of 2
VC, pale sterile cell at apex (7-11
× 2-3
µm
)
11-15 ×
6-8
3
Z. oscheoides
Ellipsoid, smooth to
minutely verruculose,
hyaline to pale-brown
7-12.5 ×
4-9
Dark brown below, hyaline,
clavate and smooth at the
apex
30-60 ×
3-4
Dark brown, arising from SC, 1
per SC
9-18 ×
7-9
2
Z. pacificum
Ellipsoid, tuberculate,
pale brown
11-16 ×
6.5-7.5
Dark brown below, hyaline,
clavate and smooth at the
apex
53-61 ×
3.5-5
Dark brown, arising from SC, 1
per SC
19-28 ×
8-12.5
2
Z. pandanicola
Spherical, tuberculate
to capitate, raised
areas flattened, brown
11-14.5 Dark brown below, hyaline,
clavate and smooth at the
apex
67-86 ×
4-5.5
Dark brown, arising from SC, 1
per SC
15.5-16 ×
8.5-9
2
Z. tonellianum
Spherical, smooth,
hyaline
8.5-10 Absent, 1-3 cylindrical stalk
cells
Stalk cells
15-50 ×
2.4-3.5
Dark brown, arising directly from
mycelium
9.5-12 ×
7-8.5
3-4
Z. tuberculatum
Spherical, spiny,
subhyaline to pale
brown, spines up to
3.5 long
12.5-16.5 Dark brown below,
subhyaline and roughened at
apex
81-98 ×
4.5-7.5
Dark brown, arising from SC, 1
per SC
15-19.5 ×
9-11
2(-3)
Z. verticillatum
Ovoid, smooth,
hyaline
6.5-13.5 ×
5-6
Dark brown below, apex
hyaline, obtuse; with brown,
apically acute lateral branch
(46.5-75 × 1.5
µm
)
6.5-25 ×
1.5
Dark brown, arising from SC, 2-3
per SC
8-15 ×
3-6.5
2

220
cell slightly enlarged (2-2.5 µm) and obtuse, upper section of the setiform
conidiophore sterile, first cell giving rise to a single vesicular conidiophore,
basal cell concolourous with the lower parts of the setae, branching in two
directions becoming part of the mycelium and connecting the conidiophores
with each other. Vesicular conidiophores arising on the side of the first cell of
the setiform conidiophore, comprised of three cell types; stalk cell cylindrical,
brown, thick walled, smooth, 5-8 × 4.5-5 µm; vesicular cell dark brown to
black, thick walled, smooth, swollen, upwardly curved, inner curvature paler
than the rest of the cell, 15.5-16 × 8.5-9 µm; 2 conidiogenous cells.
Conidiogenous cells arise directly from the vesicular cell, monoblastic,
discrete, determinate, swollen, ampulliform, upwardly curved, smooth, pale
brown, apex obtuse, 6-11 × 6.5-9 µm. Conidia 11-14.5 µm diam., solitary, dry;
initially globose, hyaline, smooth; spherical to broadly ellipsoid, aseptate,
brown, thick-walled, covered by brown, raised, flattened, tuberculate
ornamentation at maturity.
Habitat: Known to inhabit decaying leaves of Pandanus simplex.
Known distribution: Philippines.
Material examined: PHILIPPINES, Luzon Island, Quezon Region, Laguna, Baranggay
Bakas Luisiana, on decaying leaves of Pandanus simplex, 22 October 1996, S.R. Whitton
[HKU(M) 12919, holotype designated here]. PHILIPPINES, Luzon Island, Quezon Region,
Laguna, Baranggay Bakas Luisiana, on decaying leaves of Pandanus simplex, 22 October
1996, S.R. Whitton [HKU(M) 12918]; Luzon Island, Quezon Region, Laguna, Baranggay
Bakas Luisiana, on decaying leaves of P. simplex, 23 October 1996, S.R. Whitton [HKU(M)
12909, 12917, 12920].
Notes: Conidiophore morphology and conidial shape in Z. pandanicola is
similar to Z. majus, Z. minus, Z. oscheoides and Z. pacificum. In Z. pacificum
the conidia are elliptical and pale brown whilst in Z. oscheoides the conidia are
smooth or minutely verruculose, pale in pigmentation, elliptical, and the
vesicular conidiophores are produced both on the setiform conidiophores and
directly from the superficial mycelium (Ellis, 1971). The conidia of Z. minus
are smaller (6-9 µm diam.), hyaline to pale and verruculose, and those of Z.
majus are generally larger (13-18 µm diam.), verrucose and pale brown (Ellis,
1971, 1976; Pirozynski, 1972).
Acknowledgements
S.R. Whitton would like to thank The University of Hong Kong for the award of a
Postgraduate Studentship. T. Umali is thanked for organising the Philippines collection trip. J.
Wright is thanked for specimens collected in Vietnam.
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