Figs. 6-11, 12, 14, 17, 21

(1)

PERSOONIA

Published bythe Rijksherbarium /HortusBotanicus,Leiden Volume 14, Part 4,_pp.587-596 (1992)

587

Two confused Boletes in the Benelux,

Boletus

impolitus

Fries and Boletus

_depilatus

Redeuilh

P. Heinemann & J. Rammeloo

Boletusimpolitusand B.depilatusareknown fromtheBenelux;upto nowthe latter is foundonlyinBelgium.Bothspeciesoccur oncalcareous soils;B.depilatus, however, seemstoprefersoils witha_highercalcium contentthan B._impolitus.Themostreliable diagnosticcharactersarefound in thepileipellis,atboth themacroscopicaland the

micro-scopicallevel.It ispossiblethat B.depilatusismorethermophilous.

The

_analysis

of herbarium material from the Benelux showedaclear-cut

separation

into

two_groups

_{corresponding}

tothetwospecies

recognized by

Redeuilh. The fieldnotes

_accompanying

the collectionsare oftentoo

poorto

permit

a

'synthetic'

description.

Sowe decidedtodescribe

_only

onecollection of each

_{species, only citing}

the

others.

Boletus

impolitus

Fr.—

Figs.

6-11, 12, 14, 17, 21

Boletusimpolitus Fr., Epicr.:421 (1838).

Pileus 12cm indiam.,thick(1.5cm athalf theradius),

minutely

feltedto

felted-subgran-ulose,ochraceous

_yellow

(Munsellbetween 2.5 Y 8/6 and

_{7/6), locally}

darker(Mu.2.5 Y7/6 to6/6) orwith vague reddish brown tints when bruised.

Stipe

7 x 2.4cm,

cylindric

with clavate base upto3.2cmindiam.,

bright yellow

(Mu.5 Y8/8),

entirely minutely

flocculose-subsquamulose,withslight vinaceous redto

pinkish

zone atabout 2.5cmfrombase,later

(probably

on

handling) squamules

and

_{locally background turning}

brick red(Mu.ca.2.5 YR

4/8).

Flymenophore

emarginate-adnate;

tubes rather

_long

(ca. 1 cm);poresroundish, small,

upto2 mm diam.,dark olive

_yellow

(Mu. 5 Y6/8). Context

_{pale yellowish,}

rather

_bright

yellow

above tubes and beneath

_{stipitipellis, unchanging;}

smellweak,somewhat chemical.

* _{Faculte des Sciences}

Agronomiques,B-5030Gembloux, Belgium.

** _Nationale_Plantentuin

vanBelgiS,B-1860Meise,Belgium.

Inthe_past,Boletus

_impolitus

has been consideredasawell characterized

_{species being easily}

recognized

in the field

_by

its iodoformodour,which is

_{perceptible especially}

atthe base of the

stipe.

Recently,

Redeuilh(1986) described Boletus

_depilatus

which

_{macroscopically}

_strongly

resembles B. impolitusand hasan

analogous

smell.

_According

toRedeuilh both

_species

are

easily recognized

atthe

_{microscopical}

level,B.

impolitus having

a 'trichoderme constitue en

majorite d'hyphes

allongeesrelativement minces termineesen

partie

par des extremites arrondiesourenflees

plus

oumoins differenciees mais presque

toujours

identifiables', where-asB.depilatushas _a'structurenettementsubcelluleuse,aumoins

partiellement.'

Thename Boletus

_impolitus

has thus been usedatleast fortwodifferent

_species.

(2)

(3)

HEINEMANN & RAMMELOO: Two confused boletes 589

NH4OH:

pileus orange-ochraceous;

NH3 (vapour):

pileus immediately

darkvinaceous; KOH:on

pileus

dark reddishbrown,on

pale

context

_{pale pinkish-brownish,}

on

bright yellow

contextbrown; FeSC>4 (crystal): onpileusdark greytoblackish, on contextsomewhatsordid olive

_{(everywhere);}

Formol:noreaction.

Spores

(10.5-)10.8-12.45-14.1x 4.3-4.89-5.4pm(Q =

_{2.25-2.56-2.86(-2.93);}

n =35),

_{pale yellowish}

brown,

_elongate,

with roundish apex, with a

slight supra-apicular

depression;

wall ratherthin,

rarely

withan

apical thinning;

in Melzer's reagentatfirst

_greyish

(flushing

reaction)then

_light

reddish brown. Basidia(24-)30-39x9.2-11.9pm,4-spored,

hyaline. Cystidia

sparse,

46-55

x7.5-11.5pm,

narrowly

lanceolate,

slightly

sinuous,

thin-walled,

hyaline.

Gill-tramaregular, composedoflong, hyaline, cylindrical

hyphae

of 4-7pm diam.;

subhymenium

ramose.

Pileipellis only slightly

differentiated,in the upperpart the

hyphae predominantly

erect, then±intricate;

hyphae cylindrical

4-8pmindiam.;

underlying

contextwith somewhatbroader,

entangled hyphae, slightly

lacunose.

_{Stipitipellis composed}

ofa

disrupted hymenium

with basidia

_high

on

stipe.

S.E.M.

_—Spores

smoothor

only

slightly

rugose (x 20,000). Hab it a t.—Deciduous woodlandon± calcareous soils.

Described collectio n.—NETHERLANDS: Laagveendistrict: Oegstgeest, Rhijnhof, 29.09.1985, Bas8405 (L).

Other collections examined.—NETHERLANDS: Laagveendistrict:Oegstgeest, 10.08.

1980,Bas7637 (L); id., 28.08.1981,Bas 7784 (L); Breukelen, 12.08.1972,de Vries s.n.(L); id.,20.07. 1974,Daams 74.51_{(L); id., Kuyper}2216 (L).Gelders district_: _Zeist, _13.09.1953,Schutz s.n.CL); id., 26.07.1981, Kuyper1640(L); Utrecht, Bunnik, 23.08.1967,Arnolds s.n.(L); id., 15.10.1981,Schreurs s.n. (L); id., 30.08.1982,Schreurs s.n.(L); Langbroek, 08.08.1977,Bas 7212 (L); _Wageningen,21.07.1953,

Huysman s.n.(L).Fluviatiel district: Hemmen, 20.08.1966,Tjallingiis.n. (L); Ridderkerk, 09.08.1986, Noordeloos 8612 (L).—BELGIUM: Brabants district:Meise, 7.10.1976,Leonard 6904(BR); id., 18.09.1980), Leonard 7254 (BR); id.,1983,Rammeloo8194(BR); id., 27.09.1988,De Meulder 4232 (BR).Maasdistrict: Obourg, 07.07.1975,Pierart75 791 (UniversitédeMöns).

The field-notesof the cited collections allowustoadd furtherdetails tothe

_description.

The

_pileus

becomes sometimes

_squamulose

and

_rarely

showsalocal

tendency

to

redden-ing;

its

_margin

_{may be}_very

_{slightly exceeding.}

The

_stipe

is

_generally

clavateor somewhat bulbous

_(Figs.

6-8).The

_hymenophore

is

_generally

saidtobe

_{bright yellow}

atfirst. A

_slight

blueing

has been noticedonce. Thecontextexhibits

_rarely

_avinaceous tint in the

_pileus;

the smell is

_constantly

'chemical', sometimes

_{recognized formally}

asiodoform-like

_especially

at the base of the

_stipe;

thetasteis described several times assweetish

_(sugar-like)

atfirst, then

slightly unpleasant.

Boletus

_depilatus

Redeuilh—

Figs.

1-5, 13, 15, 16, 18-20,22

BoletusdepilatusRedeuilh inBull, trimest. Soc.mycol.Fr.101: 389 ('1985')1986. Boletus impolitusauct.p.p.

Boletusdepilatus. Kuyper

1207). —3. Elements of thepileipellisatthe

centreof thepileus(Kuyper 1207). (Garcin s.n.). Kuyper 1207).

Boletus impolitus. Daams

Schreurs 15.10.81). Schreurs 15.10.81;

Bas7212).

Heinemann 8172).

—2. Sketch ofsection,after fresh material(

—1. Habit sketches ofcarpophoreandsection,after fresh material(

Figs. 1-5.

—5.Elements of

pilei-pellis atthepileus margin ( Figs.6-11.

—4. Elements of thepileipellis

—6-8. Habit sketches ofcarpophores,after fresh material (6:

(4)

(5)

HEINEMANN & RAMMELOO: Two confusedboletes 591

Pileus 9.5cmindiam.,rather thick(1 cm),

pulvinate,

matt,uneven, reddish brown.

Stipe

15.5x2.7cm,solid, isodiametric,

slightly

narrowed towards top, attenuatedto

slightly

root-ing

atbase,

yellowish, locally

reddish,

paler yellowish

whiteatbase,

finely

floccose,

espe-cially

attopstriate,

loosely

fibrillose with fibrils

_forming

a± loose network.

_Hymenophore

ventricose,

deeply emarginate, nearly

free,

pale yellow

then

_slightly

olivaceous,

easily

sepa-rable from context; tubes

long (up

to 1.7cm) not

_{easily separable}

fromone another;pores small. Context

_{pale yellowish}

to

yellowish,

very

faintly blueing;

odour

_unpleasant,

not recog-nized

_formally

asiodoform-likeatthe base of the

stipe.

Exsiccatumochraceous; odour strong,

slightly

nauseous.

NH4OH,onfresh

pileus: immediately

dark blue thenblack,

becoming

brown,

changing

in less than1 minute.

Spores

10.0-11.91—14.0(-14.5) x _{3.9-4.63-5.5 pm} (Q =2.00-2.60-3.36(-3.58); n =29),

_{yellowish, slightly}

orthochromatic in Melzer's reagent,

_elongate,

with roundishor

slightly

conical apex, sometimes with a

slight supra-apicular depression; apical

pore absent. Basidia 32-40x 10.2-12.5 pm,

(l-)2(3-4)-spored,

clavate,

hyaline.

Cystidia

27-55x 8-14.5pm,more

frequent

nearandat_pores,lanceolate,with apex

elongate cylindraceous

or ± roundedoreven

narrowly subcapitate;

atandnearpores apexmore

elongate.

Gill-trama

subregular,

with

_{long hyphae}

of 4-10 pm diam.

Pileipellis

witherect

_{hyphae composed}

of ± inflatedcells, some

globulous,

others

_elongate,

the terminalone

generally

shorter, even

sphaerocyte-like, rarely

attenuated,10-40x7.5-39pm;

underlying

contextlacunose with

hyphae

withinflated,more

elongate

cells, (8-)17-30 pm indiam.,interwoven.

_Stipe

surface with

_{cylindraceous hyphae,}

_{6-22 pm in}diam.; flocci,

especially

in upper part, formed

by

hymenial

elements

_comprising

basidia.

_Clamp

connections absent.

S.E.M.—Spores

smoothor

slightly

rugose(x

20,000).

Habitat.—Deciduous woodlandoncalcareous soil.

Described collectio n.—BELGIUM: Brabantsdistrict:Tervuren,underFagusandCarpinus, beside apond, 31.08.1989,Heinemann 8172(BR).

Other collections examine d. —BELGIUM: Brabants district:Hoeilaart, Zoniënbos,12.10. 1970,Heinemann4931', Uccle, 20.09.1987,Heinemann8038 (BR). Maasdistnct: Han, Belvaux,laChefin, 02.10.1970, Kuyper1207(L); Nismes, Matricolo, 12.09.1971,Heinemann 5102(BR); Couvin, 25.09.1970, Heinemann4893(BR); Couvin, 18.09.1975,Marchal 75.163 (BR).

FRANCE: Trélon(Nord),forêt deTrélon, 13.09.1981,Heinemann 7302 (BR); Pont-de-Claix (Isère), 12.08.1987,Garcins.n.(BR).

Details of the

_analyzed

collections

_permit

usto

complete

the

description

of B.

_depilatus

basedonHeinemann8172.

The

_pileus

isvelvetyand sometimesminutelycracked. Thiscanbe

_{explained by}

the

micro-scopical pileipellis-structure.

With age the surface becomes somewhat scrobiculate i.e. with small shallow

_{depressions. Occasionally}

vinaceous reddish tintsareobserved;thenarrowouter

margin

may be reddish brown. The

hymenophore

isatfirst

decidedly

clear

_yellow.

The

con-text sometimes shows noblueing;avinaceous red

tinge

mayoccurunder the

pileipellis.

The

—13. B.depilatus (Marchal

75.163).

Figs. 14,15.Stipitipellis structure.—14.

(Léonard6904). B. depilatus B.impolitus B.depilatus —17. (Bas 8405). B.depilatus. (Heine-mann8172). (Kuyper1207). Boletus _impolitus (Kuyper1207). (Heinemann 8172).

Figs. 18, 19.Pleurocystidiaand hymenialelementsof

—19. Near the_pores

Figs. 12,13._Pileipellis structure.—12.

Figs. 16,17.Cheilocystidia.—16.

—18.Deeplyin the tubes

(Kuyper1640).— 15.

(Figs. 12, 13,x 350;Figs.14-19,x875).

(6)

smell is sometimes

_formally

iodoform-likeoriodine-likeatthe base of the

_stipe;

the exsicca-tum

_(recently

made)hasasomewhatnauseousmelleous smell. Thetasteismild, bolete-like.

Microscopically

the lacunosestructureof the

_underlying

contextof the

_pileipellis

doesnot exist in younger

sporophores.

Illustrations of B.

_depilatus

are veryscarce. Old

plates

attributedtoB.

impolitus

may

re-presentB.

_depilatus

aswell, but in the absence of herbariummaterial assimilationsare doubt-ful. Redeuilh(1986)

gives

two

plates

from which

_only

one

figure

(middle

right

of

_plate

241)

hasan

acceptable

colour,the other

_{carpophores being printed}

with a

dominating

blue

_tinge.

Estades & Lambert(1986)

published

a

plate

which is toored; this

_plate

hasbeen,

_equally

badly, reproduced

in acalendar of the Federation

_{Mycologique Dauphine-Savoie (January}

1989).The

plate

ofPeltereau,

reproduced

by

Redeuilh(1986),has the correct colours but could

_just

as

easily

be B.

_impolitus.

HABITAT AND DISTRIBUTION

Both

species

are,atleast

locally,

limitedto more orless calcareoussubstrates,B.

_depilatus

perhaps

more

strictly

than B.

_impolitus.

Fig.20.Comparisonof the_spores of Boletus impolitus(O)and B. depilatus (•);x-axis:meanlengthin μm;y-axis:mean_{width in μm.}

(7)

HEINEMANN & RAMMELOO: Two _confusedboletes 593

Inour

region, thermophily

and

calcarophily

are not

easily separated.

Boletus

_depilatus

is

possibly

asouthern

_species

whose northern limit lies in

_Belgium

where itappears

sporadically

inwarmerhabitats.

Boletus

_impolitus

israrein the Netherlands(Arnolds, 1984).The rathernumerous collec-tions_aremade in_alimited number oflocalities,

apparently

well knowntothe Dutch

mycol-ogists, indicating

that the

species

isconstantin these habitats.

In

_Belgium,

B.

_impolitus

is

_{formally reported}

for the first time

_by

Leonard(1977) in the National BotanicalGarden,Meise. This

_species

is

_{subsequently reported nearly}

_{every year}at thesame

place.

It has tobe consideredasa rare

species,

the senior author(P.H.)never col-lected it himself inmorethan 50 years.

DISCUSSION AND CONCLUSIVE REMARKS

If the affinities of thesetwoboletes isoutofdiscussion, their taxonomic

_position,

evenso, remains unreliable.

The delimitationof Bolete genera is far from

being

solved. Two tendencies exist:

recog-nizing

a

large

number of small generaoronlyafew 'traditional'ones.The differencebetween both tendencies isnotthat

_important:

authors

using

a

large

genusconceptare

obliged

tocreate

infrageneric

taxa

corresponding generally

tothe small generaof the

splitters.

Boletus

_impolitus

has been

_assigned

toatleast three genera:Boletus, Xerocomus,and Lec-cinum. For the time

_being

wereserve

judgement,

somecharacters

(e.g.

thestructureof the tubetrama)havetobe studied inmoredetail for the boletes.

Recently,

Sutara (1989)

using

the anatomicalstructureof the

_{stipitipellis, places}

both

_species

in Leccinum and considers B.

im-politusasynonym of Leccinum

fragrans

(Vitt.) Sutara.

Boletus

_impolitus

and B.

_depilatus

arevery

closely

allied

_species

which sharemostof their

macroscopic

and

_microscopic

characters. The

_pileipellis

structureis themostreliable

diagnos-tic character.

Redeuilh(1986) groups both

species

in a

'stirpe impolitus'

of Boletus. This

_'Stirpe'

is

essentially

characterizedbythe

_finely

flocculose

_stipe,

the ± chemical iodoform-like smellat the base of the

_stipe,

the

_yellow

_pores

_exhibiting

thesame

general

coloration and

discolora-tion,a

blueing generally being

absentorbeing

only

very faint.The

hymenial

charactersare notdistinctive with

_regard

toother Boleti.

_{Macroscopically,}

the distinctive charactersare

mostly quantitative:

colour range, scrobiculation of the

pileus.

The aspect of thepileussurface seen undera

good

lens allowsone toguess the

microscopical

structure. Themostobvious

macroscopical

feature,yetonethat isnot

_{always adequate,}

isthe

_shape

of the

_stipe

which is

generally

attenuated and

_{nearly rooting}

in B.

_{depilatus (Figs.}

1, 2).

Spores

and spore dimensionsare notdistinctiveasshown in TableIandFig.20.

The

_{slightly larger dispersion}

_{of the spore dimensions of B.}

_{impolitus (Fig.}

20)cannotbe

regardedas

being important.

Both collections with themean

length

lower than 10 |imconcern very young

specimens

in which it is hardtofind sufficient spores thatcanbe consideredtobe mature.

The

_pileipellis

structure is untilnowthe best charactertoseparate thetwo

_{species (Figs.}

(8)

(9)

HEINEMANN & RAMMELOO: Two confused boletes 595

specimens.The

_underlying

_context,_justbeneath themost

_{superficial hyphae,}

is lacunose in the

_specimens

_{described but the examination of young}

_sporophores

didnotconfirm this

pecu-liarity.

The lacunosestateis formed with

_ageing.

Nevertheless there isaclear-cut difference in

the context,evenin young

sporophores.

In B.

_impolitus

the

_hyphae

are±cylindricalwhereas in B.

_{depilatus they}

areinflated. Other

_{microscopical}

characters have

_proved

tobe ofno

diag-nostic value. Boletus depilatus L Ls W Ws Q Qs Heinemann 7302 11.39 1.05 4.53 0.31 2.51 0.23 Heinemann 4931 11.74 0.65 5.01 0.35 2.35 0.16 Heinemann 8172 11.82 1.23 4.65 0.39 2.56 0.37 Heinemann 8038 12.36 1.15 4.79 0.28 2.58 0.23 Marchai 75.163 12.69 0.80 5.00 0.27 2.54 0.17 Garcin s. n. 12.88 0.54 5.22 0.24 2.46 0.11 Heinemann 5102 13.35 1.26 5.12 0.26 2.61 0.24 Kuyper1207 14.09 0.80 5.10 0.47 2.78 0.22 Heinemann 4893 14.15 1.15 5.03 0.38 2.82 0.27 mean 12.62 - 4.94 - 2.55 -Boletus impolitus L Ls W Ws Q Qs Arnolds s.n. 9.19 0.84 4.12 0.38 2.23 0.16 Bas 7212 9.86 0.51 4.20 0.24 2.35 0.12 Schutz s.n. 10.49 1.04 4.20 0.24 2.50 0.26 De Vries s. n. 10.91 1.11 4.69 0.33 2.32 0.15

Boletus impolitus (continued)

L Ls W Ws Q Qs Heinemann 2937 11.05 1.03 4.50 0.25 2.45 0.18 Kuyper2216 11.45 0.49 4.83 0.28 2.37 0.15 Bas 7784 11.64 0.78 4.55 0.24 2.56 0.13 Huysman s. n. 11.88 1.51 4.87 0.39 2.43 0.24 Kuyper2811 12.02 0.65 4.99 0.22 2.41 0.15 Bas 7637 12.06 0.56 5.23 0.44 2.32 0.24 Daams 7451 12.36 0.62 4.66 0.18 2.65 0.17 Tjallingiis.n. 12.40 2.07 5.07 0.66 2.45 0.30 Bas 8405 12.45 0.83 4.87 0.28 2.56 0.15 Schreurs s.n. 12.47 1.09 5.45 0.56 2.30 0.22 Piérart 75791 12.69 1.45 4.89 0.30 2.61 0.31 Rammeloo 8194 12.93 0.81 5.28 0.31 2.45 0.19 Heinemann 7330 13.78 1.05 5.25 0.30 2.62 0.16 Schreurs s. n. 14.06 1.26 5.25 0.33 2.68 0.22 mean 11.87 - 4.83 - 2.46 (Garcin s.n.). (Kuyper 1640).—22. In

Table I:_{Spore parameters}based onthemeasurementsof 30 spores in side-view. L:length;Ls: standard devia-tiononlength;W:width;Ws: standard deviation onwidth; Q: L/W; Qs: standard deviation onQ.

Figs. 21,22._Pileipellis structures. —21.InB.impolitus B. depilatus

Boletus depilatus Boletusimpolitus i(continued)

L Ls W Ws Q Qs L Ls W Ws Q Qs Heinemann 7302 11.39 1.05 4.53 0.31 2.51 0.23 Heinemann 2937 11.05 1.03 4.50 0.25 2.45 0.18 Heinemann4931 11.74 0.65 5.01 0.35 2.35 0.16 Kuyper2216 11.45 0.49 4.83 0.28 2.37 0.15 Heinemann8172 11.82 1.23 4.65 0.39 2.56 0.37 Bas 7784 11.64 0.78 4.55 0.24 2.56 0.13 Heinemann 8038 12.36 1.15 4.79 0.28 2.58 0.23 Huysman s.n. 11.88 1.51 4.87 0.39 2.43 0.24 Marchai 75.163 12.69 0.80 5.00 0.27 2.54 0.17 Kuyper2811 12.02 0.65 4.99 0.22 2.41 0.15 Garcin s. n. 12.88 0.54 5.22 0.24 2.46 0.11 Bas 7637 12.06 0.56 5.23 0.44 2.32 0.24 Heinemann 5102 13.35 1.26 5.12 0.26 2.61 0.24 Daams 7451 12.36 0.62 4.66 0.18 2.65 0.17 Kuyper1207 14.09 0.80 5.10 0.47 2.78 0.22 Tjallingii s.n. 12.40 2.07 5.07 0.66 2.45 0.30 Heinemann 4893 14.15 1.15 5.03 0.38 2.82 0.27 Bas 8405 12.45 0.83 4.87 0.28 2.56 0.15 mean 12.62 - 4.94 _ 2.55 _ Schreurs s.n. 12.47 1.09 5.45 0.56 2.30 0.22 Boletus impolitus L Ls W Ws Q Qs Piérart75791 12.69 1.45 4.89 0.30 2.61 0.31 Arnolds s. n. 9.19 0.84 4.12 0.38 2.23 0.16 Rammeloo 8194 12.93 0.81 5.28 0.31 2.45 0.19 Bas 7212 9.86 0.51 4.20 0.24 2.35 0.12 Heinemann 7330 13.78 1.05 5.25 0.30 2.62 0.16 Schutzs.n. 10.49 1.04 4.20 0.24 2.50 0.26 Schreurs s.n. 14.06 1.26 5.25 0.33 2.68 0.22 De Vries s.n. 10.91 1.11 4.69 0.33 2.32 0.15 mean 11.87 4.83 - 2.46

(10)

-ACKNOWLEDGEMENTS

Sincere thanksare dueto the director of the

_{Rijksherbarium}

Leiden,the herbarium of the 'University de

_Liege',

and toProf.P.Pierart for the loan of herbarium

_specimens.

Mr. D. W. Mitchell(Hartfield,

England)

is

_acknowledged

for

_improving

the

_English

text.

REFERENCES

ARNOLDS,E.(1984). StandaardlijstvanNederlandse Macrofungi.In Coolia 26(Suppl.):1-362.

ESTADES,A. &LAMBERT,M.(1986).Boletus depilatusRedeuilh (=obsonium (Paul.)Fr. _ss.Blum non ss. Paulet).In Bull. trimesL F6d.mycol.Dauphine-Savoie102: 14-16.

LEONARD,J.(1977).Boletus impolitusFr.enBelgique.In Dumortiera7-8:53-55.

REDEUILH,G.('1985', 1986).Contribution & l'etudedes Bolets. I. InBull, trimest. Soc.mycol.Fr. 101: 373-412,Atlaspi.241-242.