On Irpex zonatus

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L. RyvarJS$M?Z3z.SttUtX

Bol.Soc.Argent.Bot.28 (l-4):227-231. 1992

By LEIF RWARDEN*

Summary On Irpexzonatus.Thetypeof lipexzonatusBerk has been examined and the combination Antrodiellazonata(Berk.) Ryv.is proposed. 8 other species of which thetypeshave been examined,are

placedinsynonymywith Irpex zonatus.The generic system of Aphyllophorales is discussed and provento be illogical and in generalapragmaticsystem withoutaphylogenetic base.

Irpex zonatusBerk,wasdescribedonthebasisof

specimens collected by Hooker inSikkim in the namesand found them all torepresent thesame Himalayas. Fora longtime it wasassumed to be taxon, withIrpex zonatus asthe priorbasionym. restrictedtothisareauntilLloyd(1916)reportedit Thetaxonomicpositionof Irpex zonatusisopen , fromJapan. HeassumedthatIrpexzonatus wasthe for debate.Cunningham (1965) left it in Irpex, a same as Irpex nafrante(Murr.)Sacc. aspecimen of genus which previously wasusedfor alltypes of whichhe had received fromDr.K.Miyabein

_Ja-

hydnoid wood-inhabiting fungi. Today Irpex is

pan.He wasindeed right inhis assumptionof a circumscribed in a much more restricted sense, wide distributionof Irpexzonatus althoughhisas- suchasseeninMaasGcestcranus(1974),

Eriksson

sumed synonymy was incorrect. Irpex noharae & Ryvarden (1976) and

_Jiilich

& Slalpers (1980). (Murr.) Sacc. isactuallybased onaspecimen of Thegenusistypified byIrpexlacteus(Fr.: Fr.)Fr.a

Lopharia mirabilis(Berk.&Br.) Pal. (secIto1955).

IrpexconsotsBerk.1877wasbased onacollec- dimitic hyphal system and projecting metuloid tionmade in Kobe inJapanduringtheChallenger cystidia.Irpex zonatushassomeof these characters,

expedition. Cunningham(1965) examinedthe type i.e.itisdimitic, but itscystidia are of another type

of this species andcorrectlyplaceditinsynonymy and thegenerative hyphae have clampsat their with Irpex zonatus. Some years after he had septa.Thetypeof septationisusually seen as

im-describedIrpex zonatus receivednumeroussped- portant in the current classificationof polypores. mens collected by Hooker in New Zealand and Thereareveryfewgenera withavariable septation

apparentlyoverlooked his ownspecies fromSik- of the generative hyphae. Thus, Irpex zonatus kim.BasedonaNewZealand collection he descri- should beexcludedfrom Irpex, which also wasthe beda new speciesIrpex brevis Berk.Thisspecies conclusionofMaasGeesteranus(1974: 503).

slept moreor less inoblitvion untilLloyd onhis

restless trips to Europe started to compare the groupofgenera around Steccherinurn, J'unghuhnia

many

exotic speciesdescribedin the lastpart of the Corda,and AntrodiellaRyv.&

Johans.

The former 19th century. He immediately suspected thatIrpex ishydnoid, thetwo othersmore or less poroid. In brevis was specific with I. consots Berk, and also both the latter genera there are species with an-with I. decurrens Berk. The latter wasbasedon a irpicoid to lacerate hymenophore such as

specimen fromJapancollectedby

J.

Dickens.

I have examined the types of the following

species with simple septate generative hyphae,

Tomeit isclearthatIrpex zonatus belongsinthe

JunghuhniaCrustacea(Jungh.) Ryv.(thetypespecies MaasGeesteranus(1974)published asynopsis of thegenus) and Antrodiella americana Gilbn. &

of thegenera IrpexFr. andSteccherinurnS. F.Gray Ryv. Junghultnia and Steccherinurn are

character-and commented upon all the species mentioned 'ized microscopically by metuloid encrusted

cys-above.He was in doubt

whether

they all repre- tidia arisingfrom skeletal hyphae. Suchorgansare

sentedthesametaxonas he partlyhad notexam- absent in Antrodiella and Irpex zonatus. Thus, it ined theirtypes andpartlyused datasupported by seems logical toplaceIrpex zonatusinthisgenus.

Cunningham (Maas Geesteranus 1974: 460 and The typeof cystidia seen in Irpex zonatus isalso 466),whichinpart areinerror. seenin Antrodiella americanaso no new characters areintroduced in thegenus by including Irpex

zo-*_{Department of Botany, University of}_Oslo,_P.O._Box_1045, natus. Further arguments for thistaxonomic

dispo-Blindern,N-0316Oslo,Norway. sitionaregiven after thespecific description. An 227

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Bol: Soc.Argent. Bot.28 (1-4)(1992)

exclamation markin the followinglist of names indicatethat thetypehas been examined.The her¬

baria in which the typeshave beenexamined are lied,hyaline,negative in Melzer's solution,(4.5)

5-abbreviatedaccordingto IndexHerbariorum. 6x_{(2.5) 3-3.5 /xm.}

Type

_of

rot:White rot inhardwoods.

Substrate:Ondeadhardwoodsofmanygenera. Distribution: New Zealand, Australia, China,Sri Basionym:IrpexzonalusBerk. Hook.].Bot. 6: 168,1854 Lanka, Thailand, India,Japan.

(K!).Irpexbrevis Berk. FloraNov. Zeal. 2:181, 1855 (K!).Irpex

Basidia clavate, 4 sterigmate, 12-18x4-8_/xm. Basidiospores oblong ellipsoid,smooth

thin-wa-Antrodiellazonata(Berk.)Ryv.comb. nov.

Obs.:Thespeciesare usuallyeasyto recognize consors Berk._J.Linn. Soc. 16: 51, 1877 (K!).Irpexdecurrens _{in the field because of the effused basidiocarp with} Berk. Grevlllea 19:109,1891 (K!).Irpexkusanoi Henn.&

Shirai Bot._Jahrb.28:267, 1900 (testeIto 1955).Irpiciporus japónicas Murr. Mycologia 1: 166, 1909 (NY!). Daedalea gollaniiMass. Kew Bull. 1908: 217, 1908 (K!).Irpex cingulatus Lloyd, Lloyd Mycol.Writ.5: 795, 1918 (BPI!).Irpex ochrosim-ilis Lloyd, Uoyd Mycol.Writ.7: 1273, 1924 (BPI!).

numerousimbricatepilei,withwhitish, palebuff

or pinkishcolour. The bladder tobottleshaped

cys-tidia occur irregularly in most examined speci¬

mensandare easily overlooked.Thisisonereason

for themanysynonymscited above.

Antrodiella isas mentioned above, closely re-Basidiocarp pileate, usually effused reflexedand lated to Steccherinum, Jungliulwia, and Irpex. The imbricatewith several individualpileiarising from first three genera have generative hyphae with the same context, coriaceous when fresh, dense clamps, dimitic hyphal system with skeletal

hy-andfragile cartilaginouswhendry,pileusupto 1.5 phae,andthesporesaresmall, ingeneral lessthan

cmwide,rarelywider, 1-2cm long,butsometimes

5/xm

inlongestdimension. Thebasidiocarpshave

fusedwithadjacentpileitomore elongated wavy in most speciesa ratherdense consistency and

be-shelf likepilei,marginsharpwhen fresh, usually comesemitranslucent tocartilaginous when dry. stronglycurved inward when drying, upper

sur-

The sexuality is tetrapolar and all species in all face first whiteto paleochraceous,later palebuff genera produceawhiterot in theattacked wood. to straw coloured, in old and hibernatingspeci- Irpexisonly separated from the.others with its mensoftendarkerfrom thebase withdingy spots, simple septate generative hyphae. However, in

glabrous, wavyand usually with radial lines or Steccherinum there arespecieswith simple septate

narrowfoldsorfurrows. hyphae,suchasS.cremeoalbum Hojrtst. and S.sub¬

tlymenophore first poroid, but soondentateto’ _{crinale (Pack)}_Ryv.,_(for_descriptions_of _these spe-hydnoid astheporessplit,teeth flattened to round ciesseeEriksson, Hjortstam& Ryvarden1984).Itis

and pointed, when young pruinose, later logicallydifficultto

defend

their placein

Steccher-smoother, concolorous with the upper surface, inumand not inIrpex,sincetheyshareall generic

Trama and context dense, tough, whitish to pale characters with the latter. A key to the two

hydnoid generawill breakdownwith those two

Hyphalsystemdimitic,generativehyphae with species unless they are keyedoutasspecies.If so,it clampsatthesepta,hyaline,thin-walled, 2.5-4 /xm indicatesonly that the generic concept is highly

wide, skeletal hyphae common, straight,smooth, artificial.The charactersfurther separating these

thick-walled,hyaline, 3-7/xmwide, protrudingin generaare type of hymenophoreand thepresence

the dissepiments in a semi-parallel fashion, not orabsenceof skeletocystidia. Jungltuhniaand Art-projectingobliquely throughthe fertilehymenium trodiellaare poroid, whileSteccherinum and Irpex

are irpicoidtohydnoid. Allgenera except

Antrodi-, _{Cystidia present, but often difficult} _{to locate,} ellaare characterized bymetuloidcystidia.

smooth, thin walled, tubular to bladder like

or ventricose with swollen base and tube-like generic line in this group, is of course that the

elongated neck, hyaline and negative with sulfo whole taxonomicsystem intheAphyllophorales is benzaldehyde,embedded in thehymenium, scar- artificial.Even if most mycologists working with cely projectingbeyond thebasidia, upto 120 /xm thegroupare willingto admit this,it isnot often

longand5-18_{/xm wide at- the base, arising}from a stated.The lack of fossilsamongAphyllophorales clamp on the generative hyphae. In the dissepi- makesitverydifficulttodecide what are adaptive

mentsthe skeletal hyphae are pointedand partly charactersand whatareconservativeandcanbea

projecting,smooth tofinely encrustedandmaybe basefor a phylogenetic system. This problemis interpreted as skeletocystidia, but their encrusta- seeneasy if severalgenera are compared.A char-tion isvariable andthey arenot projectingintothe acter takenasbasic in the circumscription of

one

hymenium as normally seenfor trueskeletocysti- genusisneglectedinanother. Some examplesmay dia.

beige,upto 2mmthick.

along the spines.

The underlying problem in how to draw the

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L.Ryvarden,Irpex zonatus

B

1cm

A

C

l\

H

10 pm

D

O

¿>?

Fig.1.Anlrodiellazonula, A)basidiocarp,B)cystidiain thedissepiments,C)generativeandskeletal hyphaefrom the context, D)cystidiafrom thehymenium,E)spores.A:Coll. Petch 1912(SriLanka),B-D: Coll. Hooker,typeofIrpex zonatafrom Sikkim andE: Coll. Kobe,Japan, typeofIrpexconsors.

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Bol. Soc.Argent.Bot.28(1-4)(1992)

Scytinostroma Donkand VararíaKarst,_belong_in

the Lachnocladiaceae (Hallenberg1985).They have isthesame.Thecharactersare changingtheir im-corticoid, resupinate,light coloured and smooth to portance from onegenustoanother.One character tuberculate basidiocarps,andare mostlycharacte- treatedas adaptiveinone

genus,

issuddenly ove¬

rridingallother charactersin the nextone. Logicallyit isdifficultto defend that thecystidia binding hyphae becoming stronglydextrinoid in are secondary in importance in genera like

Hy-Melzer'ssolution. Vararia has dichohyphidia ari- phoderma and Hypoclwicium(where alltypes ofcys-

-sing in thesubhymeniumfromaterminalseptum tidia occur)sincethey arenot used as delimiting

of a generative hyphae and have a main stem characters in neither genus,and then suddenly branchingout like a tree in theapex.These di- statethat they arethe basiconesinaseparationof

chohyphidia may be interpreted as strongly con- Antrodiella and Jungliuhnia. Thismay well bethe

traded binding hyphae and no doubt thetwoge- case, but that isonlyan educatedguess and not

nera arerelatedas pointedoutbyParmasto (1971) substantiatedbyanyphylogenetic arguments.

andHallenberg(1985). Another example will illustrate the dilemma.

In bothVarariaand Scytinostromatherearespe- The genusTubuliainis Donk,ischaracterized by deswith amyloid sporesaswell asspecies with highly distinct many-rooted cystidia witha vari-non-amyloid spores.Besides, in bothgenerathere ableamyloidreactionfromonespecies toanother. areamixtureofspecieswith ornamentedsporesas The sporesare non-amyloid, smooth but highly wellas species with smoothspores(seeParmasto variable inshape from allantoid toglobose. For

illustrationsof the variation inthegenus,see Hjort-Inthe wholeof theAphyllophoralesthesituation

rizedby theirmicrostrudure.

Scytinostromaisabove allcharacterized byshort

and Hallenbergop. cit. for details).

Normallyit isassumed thatagenusismono- slant,Larsson& Ryvarden(1987).

phyletic unless stated otherwise. If we therefore If weassume that this characteristictypeof

cys-assume that both Vararia and Scytinostroma are tidium hasonlybeenevolvedonce,then

Tubulic-monophyletic,itimplies that the amyloidreaction rinis ismonophyleticanda naturalgenus.

How-andtype ofornamentation of thesporesaresecón- ever, thenwe reducesporeshapetoa secondary darycharacters established after the evolution of characterevolvedin Tubulia inis afterthe

establish-the ancestral species withdichohyphidiaand bind- ment of the uniquecystidiumintheancestral spe-inghyphae respectively. If this conclusion iscor- des.Whàtistheevolutionarypressurefor the dif-rectitwill haveconsequencesfor othergenera of ferent type ofsporesin thegenus? Isitmoreor less

theAphyllophoiales.

Hypoclwicium

_J.

Erikssinthe Corticiaceaeis abo- significant character? Isitconnectedtosome for

us

ve all microscopically characterized by thick-wa- unknown pleiotropic genes? We are completely

lied, cyanophilousspores,clampsat thesepta of ignorantastoanswerstothesequestions.

thegenerativehyphaeandfairly largebasidia. The

accidental and connected tosomeother, tous

in-Thegenus Litschauerella Oberw. is seemingly genus as currently defined (see

_Jiilich

&Stalpers closely relatedtoTubulicrinishaving the same type

and Eriksson&Ryvarden op.cit.fordetails) isba- of multi-rooted cystidia.Thesporesof

Litschaua-sedon the fairly large, thickwalled cyanophilous ella,however,are- globose(as inmanyTubuliainis

spores,beingeither smoothor ornamented.Hypho-' _species) _and _ornamented _and _{not smooth} _as _in derma Wallr. isgenetically speakingverysimilar, Tubulicrinis.

separated bythin-walledsporesonly. Inbothge¬

nera theré are cystidiateandnon cystidiate species. ella homologous or analogous with those of

In theformergroupthecystidiavary-from metu- Tubuliainis and the spore ornamentation

secon-loidsto tubulargloeocystidia. Inthiscase,themain

*dary?

If they are analogous, then why could this emphasisisplaced on thesporecharacter,while not be thecase withmanyof the speciescurrently

the sterileorgans are neglectedat generic level.If placed inTubulicrinis?. Ifso,then thespores

char-Hypochnicium isassumed to be monophyletic, it acterisprimary andthe cystidium secondaryand

impliesthat the thick-walled cyanophilousspores Tubuliainisapolyphyleticgenus. The same typeof

wereestablishedasthe basic character before the questionscanbe raised within thegroupincluding

speciation and the microscopicalvariationwithin Steccherinum, bpex,Antrodiella andJungliuhnia.The thegenusstartedtodevelop.

.

variable

hymenophorewhich is theonly character Thequestionisofcourse whyasporecharacter- thatseparates Steccherinum and lunghulwia,is com-isassumedto besecondary comparedtothe sterile pletely neglected In other

genera

of Polyporaceae

•organsin Vararia andScytinostromawhile theop- suchas Spongipellis Pat. and TrichaptumMurr.In

positeisthecaseinHypoclwiciumin its separation the latter for example the hymenophore varies ' fromstrictly poroidT. abietinum (Dicks.: Fr.)Ryv., The questionsis:Arethecystidiaof

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L.Ryvarden,Irpexzonalus

lamellate T. laricinus (Karst.)Ryv. to hydnoid T.

fuscoviolaceous

(Fr.)Ryv. Microscopicallyall these species are almost identical, indicating that the

typeof hymenophoreisadaptiveand secondary

while themicroscopicalcharacters(including cys-tidia) areconservativeand primary.If this inter¬

pretation is accepted in Trichaptum, there is no logicdefence for notdoing soinSteccherinuinand

Junghuhnia.Weareleft withan illogicalpragmatic generic system acting primarily as a sorting mechanismwithoutphylogeneticfoundation. The

reason why thesituation isaccepted isof course

that noonefor the timebeinghasabetter system. Before any fundamental changes are imple¬ mented, we should have a much better under¬

standingof theevolutionaryprocessesbehind the establishment of thecharacters currently used for generic separation in Aphyllophorales. Any large changewillunavoidablyalso haveserious

nomen-claturial consequences, a most undesirable situ¬ ation.Whenmorebasicknowledge on the evolu¬

tionof thegrouphas beengained,it ismy predic¬

tion that Irpexwill regainitsstatusasa large com¬ prehensivegenus.Inprincipleit isonlythetypeof septation thatseparatesit fromSteccherinuinandit may be proper to mention that there are many

generalike Athelia Pers.,BotryobasidiumDonk, Hy-plwdontia

_J.

Erikss., Phanerochaete Karst., Sistotrema

Fr.andAntrodiellaRyv.where bothtypesofsepta¬ tionoccur.

In somegenera forexample BondarzeiviaSing.

and Stereuw Pers.exS.F.Gray the generative hy-phaeof the basidiocarp are invariably simplesep¬ tate. Nevertheless,clamps arepresent when these speciesarecultivated(Stalpers1978andChamuris

1988). We do not knowwhythedevelopment of theseclamps is suppressed in nature. However, suchcasesraisesomedoubtswhether thetypeof septationissoimportantasseenforexamplein the classificationof thepolypores(seeRyvarden1991 for details).

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