Mycologia, 76(1), 1984, pp. 40-50.
© 1984, by The New York Botanical Garden, Bronx, NY 10458
TAXONOMY OF CRUSTODERMA
(APHYLLOPHORALES, CORTICIACEAE)
K. K. NAKASONE
Center for Forest Mycology Research. Forest Products Laboratory. 1 Forest Service,
U.S. Department of Agriculture, P.O. Box 5130, Madison, Wisconsin 53705
ABSTRACT
y
The genus Crustoderma is emended to include nine species. and all, except C. longi­
cystidium, are associated with brown-rot decay of wood. Two new species. C . carolinense
and C. marianum, are described and illustrated. New combinations of C. corneum, C. Ion­
gicystidium, and C. patricium are proposed. Peniophora weiri Bres. is placed in synonymy
with C. dryinum. Culture descriptions are included for C. marianum and C. corneum. A key
to the species is provided.
Key Words: culture descriptions. brown-rot fungi, Corticiaceae, Crustoderma.
Crustoderma was proposed by Parmasto (1968) for Corticium dryinum Berk.
et Curt. Gilbertson (1981) transferred Peniophora resinosa Jacks. et Deard. to
Crustoderma. and C. flavescens Nakas. et Gilbn. and C. opuntiae Nakas. et Gilbn.
have been included in the genus (Nakasone and Gilbertson. 1982). Crustoderma
is emended to include information on cultural characters, associated brown-rot
decay. and the slightly thick-walled basidiospores that are important characters
of the genus. A key to the known species is included.
Because Crustoderma possesses some characters found in other genera. several
species have been placed in Hyphoderma Wallr. and Phlebia Fr. All the species
in Crustoderma and many species of Hyphoderma are characterized by welldeveloped cystidia and large basidiospores. The ceraceous or corneous basidio­
carps and the dense. thickening subhymenium are characters found in both Crus­
toderma and Phlebia. A survey indicated that Phlebia longicystidia (Litsch.) Hjortst.
et Ryv. and Phlebia cornea (Bourd. et Galz.) Parm. were species of Crustoderma.
Cultural and basidiocarp studies, meanwhile, have uncovered two new species.
Methods and materials are described in Nakasone and Gilbertson (1982).
Sometimes a drop of 10% KOH was used to separate structures in tightly agglu­
tinated specimens. Herbarium abbreviations are from Holmgren et al. (1981).
Changes and additions to the generic characterization are italicized. In the species
code, 27 refers to the presence of evenly thick-walled hyphae (Burdsall et al.,
1978). Asterisks (*) indicate cultures studied.
CRUSTODERMA Parmasto emend.
Nomenclatural type: Corticium dryinum Berk. et Curt.
Basidiocarps resupinate, effused. ceraceous to crustaceous or corneous when
dried, closely adherent to substrate; margins abrupt, narrow or thinning out; fertile
areas smooth or with scattered warts. often velutinous because ofnumerous emer­
gent cystidia, tints of yellow, orange or gray, sometimes olive-colored. Subicular
hyphae up to 7 µm diam, thin- to thick-walled, some gelatinized, hyaline or pale
yellow, nodose septate, frequently branched. Subhymenium thickening. consisting
of mostly vertical. densely agglutinated hyphae. Cystidia cylindrical to clavate,
1
Maintained at Madison, Wisconsin. in cooperation with the University of Wisconsin,
40
NAKASONE: CRUSTODERMA
41
up to 380 µm long, obtuse. often thick-walled in basal part and thinning toward
apex or thin-walled throughout. sometimes with adventitious septa, with or with­
out a crystalline sheath. Basidia narrowly clavate to cylindric, up to 80 µm long,
elongated at the base (pedunculate), sometimes thin- or slightly thick-walled, hya­
line or yellow, clamped at basal septum, 4-sterigmate. Basidiospores subglobose,
ellipsoidal or cylindrical, with slightly thickened walls, hyaline or yellow, nonam­
yloid, acyanophilous but the contents strongly stained in cotton blue.
In pure culture on MEA mats white or yellow, appressed, sometimes raised,
growth slow to rapid; negative reactions on GAA and TAA; often with a strong,
pungent odor. Advancing zone hyphae simple septate or with clamp connections;
submerged and surface hyphae nodose septate, thin- walled but often becoming
irregularly thick- walled.
Associated with a brown-rot decay of dead conifer and/or hardwood logs and
branches.
Remarks. -BecauseCrustoderma has several characters in common with other
genera, it can be difficult to recognize. The critical characters of the genus are the
velutinous hymenium. the dense. thickening subhymenium, the large cystidia, the
large. slightly thick-walled spores. and association with a brown-rot decay. Chae­
toderma Parm. (1968), another genus of brown-rot decay fungi, is similar to
Crustoderma but typically has longer basidia (up to 100 µm long) and arcuate,
fusiform spores. If the associated decay is not known, some species of Crustoderma
may appear to belong in Hyphoderma or Phlebia. However, the slightly thickwalled basidiospores can be used to identify a species of Crustoderma. Addition­
ally, in pure culture Crustoderma species do not react on gallic acid or tannic acid
agar while Hyphoderma and Phlebia species react strongly.
DESCRIPTIONS OF NEW SPEClES
Crustoderma carolinense Nakas., sp. nov.
FIG. 1
Differt a Crustodermatis cornei hyphidiis 30-45 × 23 µm: basidiosporis 8-9 × (5-)6-7µm, late
ellipsoideis vel subglobosis. hyalinis, laevis, leviter crassitunicis. Holotypus: HHB 2479. ad lignum
Castaneum sp., Shope Fork, Coweeta Experimental Forest. Macon County, North Carolina. U.S.A.,
28 July 1969, legit H. H. Burdsall, Jr., in herb. CFMR.
ETYMOLOGY: From carolinensis (L., adj.), referring to the state in which the holotype was found.
Basidiocarp annual. effused up to 100 × 40 mm, up to 500 µm thick, texture
when fresh not known. when dried corneous. adherent except for cut edges which
curl up and loosen from substrate: fertile area continuous. smooth with scattered
warts, projecting cystidia. easily seen under a 30× lens, numerous and well-spaced,
in fresh specimens Pale Smoke Gray with Pale Olive-Buff to Olive-Buff spots,
thicker and well-developed areas Olive-Gray. thinner and younger areas Avel­
laneous, when dried projecting cystidia giving a glaucous cast over fertile areas.
some fertile areas almost invisible. very thin. hyaline, smooth and noticeable only
because of the projecting cystidia: margins abrupt. fimbriate or punctiform. Light
Ochraceous-Buff to pale Cinnamon-Buff.
Hyphal system monomitic. Subiculum up to 120 µm thick. composed of tightly
agglutinated hyphae arranged parallel to substrate: subicular hyphae (3-)5-7 µm
diam, hyaline. smooth. thin-walled. nodose septate. infrequently branched. Sub­
hymenium thickening, up to 200 µm thick. composed of compact. agglutinated.
vertical hyphae: subhymenial hyphae 2.5-5 µm diam. hyaline. smooth. thin- or
thick-walled, nodose septate. moderately branched. agglutinated but easily sep­
arated in 10% KOH. Hyphidia cylindrical. often branched at apex. 30-45 × 2-4
42
MYCOLOGIA
FIG. 1. Crustoderma carolinense (HHB 2479, holotype). a. Cystidia (note scale). b. Subhymenial
hyphae. c. Basidia. d. Hyphidia. e. Basidiospores. FIG. 2. Crustoderma marianum (FP 105991, ho­
lotype). a. Cystidia. b. Subicular hyphae. c. Basidia. d. Basidiospores.
µm, hyaline, thin-walled, clamped at basal septum, smooth, arising from hy­
menium. Cystidia cylindrical to clavate, 120-380 × 14-22 µm, hyaline, protrud­
ing up to 230 µm, walls slightly thickened or thick-walled at base then gradually
thinning toward apex, clamped at basal septum, smooth or with scattered crys­
talline matter, arising from subhymenium or hymenium. Basidia clavate, some-
NAKASONE: CRUSTODERMA
43
times stalked, 52-68 × 8-9 µm, hyaline, smooth, thin-walled, clamped at basal
septum, 4-sterigmate, sterigmata up to 6 µm long. Basidiospores broadly ellipsoid
to subglobose, 8-9 × (5-)6-6.5(-7)µm, hyaline, walls slightly thickened, smooth,
nonamyloid, nondextrinoid, acyanophilous.
Remarks. - Crustoderma carolinense, associated with a brown-rot of dead chest­
nut, is known only from the type locality. Its drab, dark color and horny texture
are useful characters to differentiate it from most other species in the genus. It is
closely related to C. corneum, which also has a horny texture. However, the
broadly ellipsoid to subglobose spores, hyphidia, and very large cystidia of C.
carolinense can be used to distinguish it from C. corneum. The latter species
appears to grow exclusively on Pinus spp.
Crustoderma marianum Nakas., sp. nov.
FIG. 2
Differt a speciebus Crustodermatum basidiis 30-35 × 5.5-7.5 µm; basidiosporis (9-)10-12
(-13) × 5.5-6.5(-7)µm, ellipsoideis vel late cylindraceis, hyalinis, laevis, leviter crassitunicis. Holo­
typus: FP 105991, ad lignum Pinus sp., Telegraph Road vicinia, Beltsville Forest Disease Laboratory,
Laurel, Maryland, USA., 28 Jan. 1966, legit 0. K. Miller. Jr., et R. L. Gilbertson, in herb. CFMR.
ETYMOLOGY: From marianus (L., adj.), referring to Maryland, the state in which the holotype
was found.
Basidiocarp annual. effused up to 100 × 50 cm, up to 300 µm thick, texture
when fresh not known. when dried crustaceous, adherent; fertile area Pale Ochra­
ceous-Buff to Light Ochraceous-Buff. continuous. smooth, thinner areas floccose.
projecting cystidia easily visible at 30×; margins gradually thinning out and prui­
nose or abrupt, concolorous with fertile areas; subiculum white and cottony when
exposed.
Hyphal system monomitic. Subiculum up to 100 µm thick, composed oftightly
woven hyphae: subicular hyphae 4-5 µm diam, hyaline, smooth, slightly thickto thick-walled, nodose septate, moderately branched. easily separated in 10%
KOH. Subhymenium thickening, up to 70 µm thick, composed of compact, ag­
glutinated, vertical hyphae with embedded basidiospores: subhymenial hyphae
similar to subicular hyphae. Hymenial hyphae 1.5 µm diam, thin-walled. smooth,
hyaline, simple septate with scattered clamp connections, sparingly branched.
found in FP 105993 throughout and projecting beyond hymenium. Cystidia cy­
lindrical. sometimes swollen at base. 100-150(-190)× 8-12(-14)µm, protruding
up to 100 µm, hyaline, slightly thick-walled throughout or thick-walled at base
then gradually thinning toward apex. clamped at basal septum, smooth, sometimes
with adventitious septa. arising from hymenium. Basidia (difficult to find) clavate.
often stalked, 30-35 × 5.5-7.5 µm, hyaline, smooth, slightly thick-walled, clamped
at base, 4-sterigmate, sterigmata up to 7 µm long. Basidiospores ellipsoid to
broadly cylindrical. (9-)10-12(-13)× 5.5-6.5(-7) µm. hyaline. slightly thickwalled, smooth, negative in Melzer’s reagent, acyanophilous.
Culture morphology. Growth on malt extract agar (MEA) moderately rapid.
48-65 mm diam at 1 wk, 90 + mm diam at 2 wk. Mats white, appressed, thin,
subfelty at 2 and 6 wk; margins even, appressed, fimbriate; odor strong, pungent
at 2 and 6 wk; agar stained Baryta Yellow to Lemon Chrome. most intense under
inoculum and fading toward margins at 2 and 6 wk; not fruiting by 6 wk. Oxidase
reactions on gallic acid agar (GAA) at 1 wk negative. rarely stained yellow, growth
48-63 mm diam; on tannic acid agar (TAA) negative. rarely stained, growth 0­
trace. GAA mats at 2 wk similar to MEA mats. Microscopic characters. Advancing
zone hyphae 2-4µm diam, thin- to slightly thick-walled, simple septate, sparingly
branched. Submerged and surface hyphae (a) 4-8 µm diam, evenly to irregularly
thick-walled, simple septate with scattered single clamps, moderately branched:
44
MYCOLOGIA
NAKASONE: CRUSTODERMA
45
(b) 1.5-4 µm diam, thin-to slightly thick-walled. nodose septate. moderately
branched. Chlamydospores globose to ellipsoid, up to 20 µm diam, hyaline. thinto thick-walled, terminal or intercalary, numerous (but apparently absent in FP
94432) in submerged and surface mats at 2 and 6 wk.
KEY PATTERNS: A-0-1-1-10-16, A-0-1-1-2-10. B-O-I-1-2-10. SPECIES CODE: 1.4.7.(9).34.36.38.43­
44.53.54.55.
SPECIMENS EXAMINED: U.S.A. MARYLAND: FP 94432* on old post of Robinia pseudoacacia L.,
Beltsville: FP 105991* and 105993. on Pinus sp., Laurel.
Remarks. -Specimen Fp 105993 is fruiting over sand-like particles and thus
appears to be a much thicker fruitbody than FP 105991, the type specimen.
Specimen FP 94432, which is fruiting over the transverse surface of a wooden
post. has developed several small, discrete fruiting areas quite unlike the contin­
uous hymenial surface of the type specimen. Crustoderma marianum is known
only from Maryland and is associated with a brown-rot decay of hardwood and
conifer slash. Although lacking any outstanding characteristics, the large. ellipsoid
to broadly cylindrical basidiospores and small basidia can be used to distinguish
C. marianum from similar species.
NOTES A N D NEW COMBINATIONS
Crustoderma corneum (Bourd. et Galz.) Nakas.. comb. nov.
FIG. 3
Peniophora gigantea (Fr.) Massee spp. cornea Bourd. et Galz.. Hymen. France p. 318. 1928
(Basionym). Peniophora cornea (Bourd. et Galz.) J. Erikss. in Lundell and Nannfelt. Fungi exs.
suec. 37-38 p. 28, no. 1854. 1950. Phlebia cornea (Bourd. et Galz.) Pam., Izv. Akad. Nauk
SSR, Ser. Biol. 16: 390. 1967.
Culture morphology. Growth on MEA moderately slow to slow, trace-15mm
diam at I wk, (24-)31-50(-63) mm diam at 2 wk. Mats white. appressed. thin,
subfelty, but slightly raised. short-downy around inoculum at 2 wk, by 6 wk white,
appressed to slightly raised, subfelty to short-woolly around inoculum, becoming
slightly raised to raised, short-downy to short-woolly toward margins; margins
even, appressed; odor strong, sweet, often lemon-like at 2 wk, strong lemon-like
or pungent at 6 w k agar unchanged at 2 and 6 wk; not fruiting by 6 wk. Oxidase
reactions on GAA at 1 wk negative or rarely lightly stained, growth 0-18 mm
diam: on TAA negative or rarely stained, growth none. Microscopic characters.
Advancing zone hyphae 3-4 µm diam. thin-walled. nodose septate. sparingly
branched often from or just below clamp connections. Submerged and surface or
aerial hyphae 1.5-5 µm diam, thin-walled. often becoming evenly to irregularly
thick-walled in age, nodose septate. moderately branched. lumen often narrow,
thread-like and sinuous thus giving a false impression of irregularly thickened
walls. Bulbils present in submerged mat of 6-wk-old cultures.
KEY PATTERNS: A-O-M-1-10.A-O-S-1-10.SPECIES CODE: 1.3.7.9.22.(27).32.36.38.(46).47.53.55.
SPECIMENS EXAMINED: CANADA: J. L. Lowe 13829* on conifer, Nipigon Provincial Forest,
ONTARIO (CFMR). SWEDEN: N. Hallenberg 22739 on Pinus sylvestris L., N. Kvill National Park.
Småland 1972. 10.15 (neotype, GB). U.S.A.: HHB 5685* on Pinus contorta Dougl. ex Loud., Blacktail
FIG. 3. Crustoderma corneum (N. Hallenberg 22739. neotype). a. Cystidia. b. Basidia. c. Ba­
sidiospores. FIG. 4. Crustoderma dryinum (FP 105487). a. Cystidium. b. Cystidioles. c. Basidia. d.
Basidiospores. FIG. 5. Crustoderma flavescens (HHB 9359). a. Basidia. b. Cystidia. c. Basidiospores.
FIG. 6. Crustoderma longicystidium (K. Keissler and V. Litschauer NO. 223, isotype). a. Cystidia. b.
Basidia. c. Cystidioles. d. Basidiospores.
MYCOLOGIA
46
Mt., and HHB 5695* on Pinus ponderosa Laws., Pleasant Valley. both Flathead County. MONTANA
(CFMR).
Remarks. -Eriksson et al. (1981) have provided a detailed description and illus­
tration of this species. The basidiospores. despite having been described as thinwalled (Eriksson et al., 1981). are very slightly thick-walled.
Crustoderma corneum is associated with a brown-rot decay of Pinus species.
It is common in northern Scandinavia and has been reported from Spain. U.S.S.R.,
and Tanzania (Eriksson et al., 1981). but it is not as prevalent in North America.
This species is most similar to C. carolinense which is found on chestnut.
CRUSTODERMA
DRYINUM
(Berk. et Curt.) Parm.. Consp. Syst. Cort. p. 88. 1968.
FIG. 4
Corticium dryinum Berk. et Curt. in Berk., Grevillea 1: 179. 1873. Coniophora dryina (Berk. et
Curt.) Massee, J. Linn. Soc. Bot. 25: 135. 1889. Peniophora dryina (Berk. et Curt.) Rogers
et Jacks., Farlowia 1: 278. 1943.
= Xerocarpus laeticolor Karst.. Bidrag Kännedom Finlands Natur. Folk 37: 137. 1882.
Corticium laeticolor (Karst.) Sacc., Syll. Fung. 6: 636. 1888.
Coniophora laeticolor (Karst.) Karst.. Bidrag. Kännedom Finlands Natur. Folk 48: 436. 1889.
Coniophorella laeticolor (Karst.) Pilát, Bull. Soc. Mycol. France 49: 296. 1933.
= Coniophora crocea Karst.. Rev. Mycol. (Paris) 9: 10. 1887. Peniophora crocea (Karst.) Hoehn.
et Litsch.. Sitzungsber. Kaiserl. Akad. Wiss., Math.-Naturwiss. Cl., Abt. 1, 115: 1574. 1906.
= Peniophora tabacina Burt, Ann. Missouri Bot. Gard. 12: 334. 1925 (1926).
= Peniophora weiri Bres., Mycologia 17: 70. 1925.
SPECIMENS EXAMINED: FINLAND: P. A. Karsten No. 781, ad Pinum, Näkiä, Mustiala (ut Coni­
ophora crocea Karst., H); P. A. Karsten No. 1424, ad lignum Pini, VIII 1886, Saloinen, Mustiala (ut
Xerocarpus laeticolor Karst., H); P. A. Karsten in ligno pini, Mustiala (ut C. crocea, FH). U.S.A.:
Peters No. 709, Curtis Herbarium No. 5204, on Quercus, ALABAMA, Nov. 1854 (isotype of Corticium
dryinum, FH): C. L. Shear No. 1185 on spruce log, Ouray, COLORADO, July 24, 1897 (holotype of
Peniophora tabacina, FH); Weir No. 23345 on Pinus monticola Dougl. ex D. Don. Priest River. IDAHO,
Sept. 1914 (holotype of Peniophora weiri. BPI); FP 105487 on hardwood. M ARYLAND.
Remark -This is the most well-known member of the genus and is also the
nomenclatural type of Crustoderma. Basidiocarp descriptions can be found in
Eriksson and Ryvarden (1975), Lindsey and Gilbertson (1978), and Gilbertson
(1981). Rogers and Jackson (1943) also treated the synonymy of C. dryinum. In
the specimen illustrated (FIG. 4) slightly thick-walled cystidioles with adventitious
septa were observed although these structures have not been reported before.
Crustoderma dryinurn is associated with a brown-rot of dead coniferous and
deciduous trees and slash.
Cultures of C. dryinum available for study lacked clamp connections although
at one time clamp connections were abundant on all hyphae. Thus, no cultural
study was undertaken until fresh isolates could be obtained.
Bourdot and Galzin’s (1928) concept of Thelephora viridis Preuss is C. dryinum
(Eriksson and Ryvarden, 1975). For further discussion of T. viridis, see remarks
under C. flavescens.
CRUSTODERMA
Nakas. et Gilbn., Mycologia 74: 601. 1982.
FIG. 5
Remarks. - When Preuss (1851) described Thelephora viridis, he wrote “sporis
ovatis.” Bourdot and Galzin’s (1928) concept of it is C. dryinum which has
cylindrical spores. It seems that T. viridis is more similar to C. flavescens, which
has ellipsoid spores, than to C. dryinum. The true identity of this species may
never be known, however, as the type specimen of T. viridis is apparently lost.
There is no specimen of T. viridis from Preuss’ herbarium at Botanische Museum
Berlin-Dahlem (Jülich, 1974).
FLAVESCENS
NAKASONE: C RUSTODERMA
47
Basidiocarp and cultural descriptions of this species appeared in Nakasone
and Gilbertson (1982). The large, broadly ellipsoid to subglobose spores combined
with the Warm Buff to Cinnamon-Buff fruit bodies distinguish C. flavescens. It
is closely related to C. longicystidium; see discussion under that species.
Crustoderma longicystidium (Litsch.) Nakas., comb. nov.
FIG. 6
Peniophora longicystidia Litsch., Oesterr. Bot. Z. 77: 13 1. 1928 (Basionym). Phebia lon­
gicystidia (Litsch.) Hjortst. et Ryv., Mycotaxon 9: 507. 1979.
SPECIMENS EXAMINED: AUSTRIA. K. Keissler and V. Litschauer No. 223. on conifer wood,
Troppberg near Purkersdorf, 12-VIII-1925 (holotype UPS, isotype NY). NORWAY: E. Högholen
874/78 on coniferous wood. O Rokoskogen. Löten, Hedmark and E. Högholen 50181 on coniferous
wood, ved Sortåa. Våler, Hedmark (O).
Remarks. -Although rare, this species has been well studied (Eriksson et al., 1981;
Hjortstam and Ryvarden. 1979; Weresub, 1961; Litschauer, 1928). The basid­
iospores of C. longicystidium are slightly thick-walled (Hjortstam and Ryvarden.
1979). The type specimen has numerous slightly thick-walled cystidioles, also
referred to as chlamydospores (Eriksson et al., 1981) or paraphyses (Litschauer,
1928), in the hymenium and rather small basidia (20-30 µm long). These cystidi­
oles are rare and have been observed in only one other specimen (Eriksson et al.,
1981).
The large, distinct cystidia of C. longicystidium are similar in size and mor­
phology to those of C. flavescens. Several specimens of C. longicystidium are
recorded from Austria and Fennoscandia on coniferous hosts (Hjortstam and
Ryvarden, 1979) but it has not been reported from North America. I could not
determine the associated decay of C. longicystidium from the specimens examined,
but it probably causes a brown-rot.
FIG. 7
Basidiocarp and cultural descriptions of this species appeared in Nakasone
and Gilbertson (1982). The gray color of the basidiocarps, the relatively small
basidiospores. and restricted distribution (limited to southern Arizona) distinguish
C. opuntiae.
CRUSTODERMA
OPUNTIAE
Nakas. et Gilbn., Mycologia 74: 603. 1982.
Crustoderma patricium (G. H. Cunn.) Nakas., comb. nov.
FIG. 8
Corticium patricium Cunn., Trans. Roy. Soc. New Zealand. Bot. 82: 289. 1954 (Basionym).
SPECIMEN EXAMINED : NEW ZEALAND: PDD 11220, on Nothofagus solandri Oerst. var. cliffor­
tioides (Hook. f.) Poole, Mt. Ruapehu, Whakapapa, Oct. 20, 1949, coll. J. M. Dingley (holotype, PDD).
Remarks. -For a detailed description ofthis species see Cunningham (1954,1963).
This species is known only from Australia and New Zealand and is associated
with a brown-rot decay of hardwood branches. rarely on conifers. Its cylindrical
basidiospores (11-16 × 4.5-5.5µm) are the largest in the genus.
CRUSTODERMA
RESINOSUM
(Jacks. et Deard.) Gilbn.. Mycotaxon 12: 377. 1981.
FIG. 9
Peniophora resinosa Jacks. et Deard., Canad. J. Res., Sect. Bot. Sci. 27: 147. 1949. Hy­
phoderma resinosum (Jacks. et Deard.) K. J. Martin et Gilbn.. Mycotaxon 6: 62. 1977.
See Jackson and Dearden (1949) or Nakasone and Gilbertson (1982) for basid­
iocarp descriptions and the latter for a culture description of this species. Its
restricted distribution (Pacific Northwest and Rocky Mountain regions of North
48
MYCOLOGIA
F IG . 7. Crustoderma opuntiae (RLG 12348, holotype). a. Cystidia. b. Basidia. c. Basidiospores.
F IG . 8. Crustoderma parricium (PDD 11220, holotype). a. Basidiospores. b. Cystidia. c. Basidia. FIG.
9. Crustoderma resinosum (FP 133802). a. Basidia. b. Cystidia (note scale). c. Basidiospores.
NAKASONE: CRUSTODERMA
49
America) and its large hymenia1 elements allow for easy identification of C.
resinosum.
KEY TO THE SPECIES OF CRUSTODERMA
ACKNOWLEDGMENTS
The herbaria from the following institutions lent specimens used in this study:
University of Göteborg, University of Uppsala, University of Helsinki, University
50
MYCOLOGIA
of Oslo, Harvard University (Farlow Herbarium), U.S. National Fungus Collec­
tions, and Plant Diseases Division, Dept. of Scientific and Industrial Research,
New Zealand. Drs. H. H. Burdsall, Jr., R. L. Gilbertson, J. H. Ginns, and M. J.
Larsen reviewed this manuscript. Dr. Larsen also provided the Latin diagnoses.
LITERATURE CITED
Accepted for publication June 11, 1983