Clarifying the butter Boletes: a new genus, Butyriboletus, is established toaccommodate Boletus sect. Appendiculati, and six new species are described

David Arora1

Casa Madera Institute, P.O. Box 672, Gualala,California 95445

Jonathan L. FrankDepartment of Biology, Southern Oregon University,Ashland, Oregon 97520

Abstract: The butter boletes (Boletus s.l. sect. Appen-diculati) are an economically important group ofectomycorrhizal fungi whose basidiocarps have a yellowtube layer that often bruises blue, yellow reticulatestipe, mild flavor and firm yellow-tinged flesh that mayor may not turn blue when exposed. Morphologicalcharacters and molecular data (ITS and LSU) place thisgroup in a separate phylogenetic clade from Boletussensu stricto. Here we establish a new genus, Butyr-iboletus, to accommodate 14 species of butter boletesthat range from Asia to Europe, north Africa and NorthAmerica. We recombine eight previously describedbutter bolete species and we describe six new species:four from western USA (Bu. persolidus, Bu. primiregius,Bu. autumnigius, Bu. querciregius) and two fromYunnan, China (Bu. yicibus, Bu. sanicibus).

Key words: Appendiculati, Boletaceae, butter bo-letes, Butyriboletus, molecular phylogenetics, newgenus, new species, taxonomy

INTRODUCTION

The genus Boletus L. (Boletales, Boletaceae) has beenshown to be polyphyletic (Binder and Hibbett 2006,Nuhn et al. 2013), with the porcini (B. edulis andclose relatives) retained in Boletus s. str. and theremaining species in a state of flux (Dentinger et al.2010). Boletus L. sect. Appendiculati Konrad &Maubl. ex. Lannoy & Estades is a well defined groupof edible boletes distinguished by firm flesh, yellowreticulate stipe, yellow pore layer that in most casesturns blue when bruised, and mild-flavored, yellow-tinged flesh that may or may not turn blue whenexposed. In North America this group is popularlyreferred to as the ‘‘butter boletes’’ because of thebutter-yellow pore surface, stalk and flesh. As far as isknown the butter boletes are restricted to thenorthern hemisphere and appear to be more diverse

in temperate climes than in tropical, subtropical orboreal ones. Several species are sold in markets inEurope, the western United States, China, Japan andMexico and one species is harvested on a massivescale in Yunnan, China. Butter boletes have indirecteconomic importance in that they form ectomycor-rhizal mutualisms with commercially valuable timber(Pseudotsuga, Pinus, Abies, Quercus).

Five European butter bolete species have beendocumented in detail (Marques and Munoz 2006,Assyov 2012), but great confusion surrounds taxa onother continents. As often is the case with higherfungi, the names of European species (especiallyBoletus regius Krombh. and B. appendiculatusSchaeff.) have been liberally applied to similar NorthAmerican butter boletes (Thiers 1975, Arora 1986,Breitenbach and Kranzlin 1991, Bessette et al. 2000)and to Mexican boletes (Guzman 1997) as well asAsian members of the group (Hongo 1960). Inaddition, the name of a northeastern North Americanspecies, B. speciosus Frost, has been applied byChinese mycologists to an economically importantbutter bolete in Yunnan province (Chiu 1948, Wanget al. 2004) by Japanese mycologists to a Japanesespecies (Imazeki et al. 1988) and by Europeanmycologists (Singer 1967, Moser 1983) to a Europeanbutter bolete now recognized as B. fuscoroseusSmotlacha or B. pseudoregius Hubert ex Estades.

Taxonomic confusion is not uncommon in thatmycologists regularly have encountered new species inpoorly studied regions and struggled to settle ondistinguishing criteria. The butter bolete group hasbeen difficult to clarify to species on the basis ofmorphology. Indeed, in this study we found severalbutter bolete collections in herbaria that were misiden-tified. DNA sequence data is an additional and oftencritically useful character to support morphologicalobservations and to elucidate which morphological orecological characters are useful in distinguishingspecies. In this paper we include ITS and LSU rDNAgene sequences and set out to compare butter boletesin western USA and Yunnan, China, (two areas wherethe authors have collected extensively) with butterbolete species originally described from Europe andeastern North America. Butter boletes from other areassuch as Japan and Mesoamerica were not examined.

Recent studies have used ITS and/or LSU nrDNAdata to determined new species and genera in theBoletaceae (Binder and Bresinsky 2002, Gelardi et al.

Submitted 10 Feb 2013; accepted for publication 24 Nov 2013.1 Corresponding author. E-mail: maxfun@cruzio.com

Mycologia, 106(3), 2014, pp. 464–480. DOI: 10.3852/13-052# 2014 by The Mycological Society of America, Lawrence, KS 66044-8897

464

2013, Li et al. 2013). Both regions present difficultiesfor phylogenetic analyses and require visual examina-tion of alignments. However, in combination withother studies with congruent phylogenetic arrange-ments (Gelardi et al. 2013, Li et al. 2013, Nuhn et al.2013), these regions provide sufficient support forour morphological observations. Our goal was tosee whether the European names B. regius and B.appendiculatus have been applied correctly and thespecies are as widely distributed as the literatureindicates or whether western USA and Chinesespecies are distinct taxa, as morphological observa-tions by DA and others suggest.

MATERIALS AND METHODS

Field and herbarium collections.—Whenever possible, freshmaterial was examined by the authors and observationswere recorded on traditional morphological characters ofthe basidiocarps, such as color, surface ornamentation onthe pileus and stipe and staining reactions after cutting orbruising. Each collection was photographed, and werecorded ecological information, such as potential ectomy-corrhizal tree hosts and time of fruiting.

DA visited sites in California and other parts of USA overthe past 30 y and intensively collected butter boletes inCalifornia 2009–2012; JLF compiled collections in Califor-nia and Oregon 2011–2012. DA has collected and visitedmarkets regularly in Yunnan, China, since 1992. Several ofthe Yunnan collections were bought from markets, a usefulmeans of obtaining specimens when the specimens are ingood condition and the vendor can provide data on habitatand locality. Chiu (1948) described more than a dozenspecies of boletes from Yunnan on the basis of purchasedspecimens. Additional vouchered specimens for this studywere provided by various other collectors, and we examinedherbarium specimens at San Francisco State University(SFSU) and Oregon State University (OSC).

Spores were examined and measured from the mostmature specimen in each collection at 10003 magnificationwith the aid of an Olympus compound microscope withbright field and phase contrast and a Leica DMLB compoundmicroscope. Thirty spores from each type collection weremeasured and averaged to determine the length-to-width(Q) ratio, which proved to be useful in some cases. However,size and shape of basidia and cystidia and other micromor-phological features were not helpful in distinguishingspecies. Vouchered specimens have been deposited in theherbaria at SFSU and OSC. GPS coordinates (latitude andlongitude in decimal degree coordinates) are provided forthe designated holotypes; in most cases the coordinates werenot recorded on site but extrapolated after collection withGoogle Earth and Google Maps.

Molecular methods.—DNA was extracted from 75 (12 freshand 63 dried) basidiocarps. Tissue samples were stored andpulverized with micropestles in buffer (0.1M Tris, 0.3M NaCl,0.04M EDTA) at 4 C and extracted in 2% cetyltrimethylammonium bromide (CTAB) with chloroform.

DNA was amplified in polymerase chain reactions (PCR)with fungal specific primer ITS1F (59–ggtcatttagaggaagtaa–39) and universal eukaryote primer TW13 (59–ggtccgtgtttcaa-gacg–39) (White et al. 1990, Gardes and Bruns 1993); 20 mLPCR were performed with 0.6 units GoTaq and 4 mL 53 greenbuffer (Promega), 200 mM each dNTP, 0.3 mM each primer,2.5 mM MgCl2 and 2 mL undiluted DNA template. An initial3 min at 93 C was followed by 30 cycles of 30 s at 95 C, 2 min at54 C, and 3 min at 72 C, with a final cycle for 10 min at 72 C.When necessary shorter fragments from older herbariumspecimens, such as the type collection of Boletus abieticolaThiers, were amplified with following primer pairs ITS1F andITS4 (59–tcctccgcttattgatatgc–39), ITS1 and ITS2, and ITS3and ITS4; 20 mL PCR were amplified as above with theannealing temperature reduced to 51 C and the extensiontime reduced to 2 min. PCR products were electrophorescedon 1.5% agarose gels, stained with GelRed nucleic acid stain(1 mg/mL) (Biotium) and visualized with a Kodak EDAS290 UV transilluminator.

PCR products were purified with QIAquick PCR purifica-tion kits (QIAGEN, Valencia, California), prepared withBigDye Terminator Ready Reaction Mix 3.1 and sequencedwith an ABI 310 Genetic Analyzer (Applied Biosystems, FosterCity, California) in the Biotechnology Center at SouthernOregon University. Molecular data were obtained by sequenc-ing the internal transcribed spacer (ITS) region, includingITS1, the 5.8S ribosomal DNA gene and ITS2, and part of the28S ribosomal gene, with forward primers ITS1F, ITS1 (59–tccgtaggtgaacctgcgg–39), ITS3 (59–gcatcgatgaagaacgcagc–39)and ITS4r (59–gcaatatcaataagcggagga–39), and reverse prim-ers ITS2 (59–gctgcgttcttcatcgatgc–39), ITS4 and TW13.

Individual sequences were edited with Chromas 1.45(McCarthy 1998). Contiguous sequences were assembled inSequencher 4.7 (Gene Codes Corp., Ann Arbor, Michigan)and compared to other fungal ITS and LSU sequences inGenBank with BLAST (Altschul et al. 1990). Boletus rubripeswas used as outgroup for the ITS dataset. Paxillus involutuswas used as outgroup for the LSU dataset. MAFFT andClustal X were used to generate multiple sequencealignment (Thompson et al. 1997, Katoh et al. 2002).Alignments were edited manually and visually assessed forregions of homology with BioEdit and Mesquite (Hall 1999,Maddison and Maddison 2011).

Phylogenetic trees, using maximum likelihood, weregenerated with fastDNAml (Felsenstein 1981, Olsen et al.1994) through the Mobyle portal of the Pasteur Institute(http:/mobile.pasteur.fr) and MEGA 5 (Tamura et al.2011). Phylogenetic trees, using parsimony with 1000bootstrap replicates and 1000 jack-knife replicates, weregenerated with PAUP* 4.10b10 (Swofford 2002). Consensustrees with 50% majority rule were generated with a tree-bisection-reconnection branch-swapping algorithm. Allcharacters were given equal weight; gaps were treated asmissing. For the LSU tree, evolutionary history was inferredwith the minimum evolution method (Rzhetsky and Nei1992). When the number of common sites was less thanone-fourth of the total number of sites, the maximumparsimony method was used; otherwise BIONJ method withMCL distance matrix was used. All positions containing gapsand missing data were eliminated. Consensus trees were

ARORA AND FRANK: BOLETES CLARIFIED 465

examined to confirm branch positions. Trees and aligmentswere deposited at www/TreeBASE.org

RESULTS

DNA sequences were generated from 75 boletecollections and deposited in GenBank, accessionnumbers KC184411–KC184489 and KC584784–KC584791 (TABLE I). We generated ITS data from 61collections and aligned these with an additional nineITS sequences from GenBank and two from Unite;a total of 776 characters were aligned, with 466remaining constant, 100 variable and 210 parsimonyinformative. LSU data from 19 collections were alignedwith an additional 21 LSU sequences from GenBank;a total of 501 characters were aligned, with 362remaining constant, 32 variable and 107 parsimonyinformative. The optimal LSU tree with the sum ofbranch length 5 0.78036770 is illustrated. Alignmentshave been deposited at http://purl.org/phylo/treebase/phylows/study/TB2:S13879.

These data support the recognition of four NorthAmerican and two Chinese butter boletes as new taxadistinct from each other and from the Europeanones. Analysis of pairwise comparisons among allspecies in the new genus reveal base pair differencesof 2–5% among species concepts. The closestgrouping of species is the western USA red-cappedbutters, Bu. primiregius, Bu. autumniregius and Bu.querciregius, which differ from each other by . 2% inthe ITS regions. All other species in the new genusdiffer by . 5% in the ITS regions. ITS analysissuggests an affinity between Bu. fechtneri and Bu.sanicibus. However, other than the western USA red-capped butters and the Bu. fechtneri-sanicibusbranch, there is low support for clustering specieswithin the genus.

The butter boletes as a whole (including Europeanspecies) merit generic recognition now that Boletus s.str. has been reserved for B. edulis and its cognates(Dentinger et al. 2010). In their phylogenetic review ofthe Boletinae, Nuhn et al. (2013) recognized a ‘‘B.regius’’ clade that encompasses the butter boletes,clearly distinct from the ‘‘porcini’’ clade. While somebranches within the new genus are not stronglysupported, our ITS and LSU phylogenetic analysesdemonstrated that the butter boletes form a monyphy-letic clade separate from the core porcini group(FIGS. 1, 2). Support for this clade also was found byGelardi et al. (2013). Although the LSU tree did notresolve all branches among other related species, thenew genus is strongly supported with a 90% bootstrapvalue. We therefore propose the genus Butyriboletus toaccommodate the butter boletes. Supported by ITS andLSU data and morphological observations, we transfer

eight existing taxa to this genus and describe six newspecies: four from California, USA, and two fromYunnan, China.

TAXONOMY

Butyriboletus D. Arora & J. L. Frank, gen. nov.MycoBank MB803207

Basidiocarps epigeous and stipitate. Pileus mostlybrown to reddish; tube layer yellow, often turningblue when bruised, stipe yellow or reddish tinged andreticulate over the upper portion; context of pileuspale yellow, turning blue erratically if at all when cut;context of stipe often vinaceous-tinged at the base.Spores fusoid, smooth, brown (olive brown in mass);pileipellis a trichodermium.

MycoBank MB803319Type: Butyriboletus appendiculatus (Schaeffer) D.

Arora & J.L. Frank, comb. nov.

Etymology: butyrum (L.) 5 butter; Boletus appendiculatus Schaeffer, Fung. Bavar. Palat. 2:

tab. 130. 1763.

These published species are transferred to Butyr-iboletus:

Butyriboletus abieticola (Thiers) D. Arora & J. L. Frank,comb. nov.

MycoBank MB803317; Boletus abieticola Thiers, California Mushrooms: a field

guide to the Boletes: 39. 1975.

Butyriboletus brunneus (Peck) D. Arora & J. L. Frank,comb. et stat. nov.

MycoBank MB803325; Boletus speciosus var. brunneus Peck, Ann. Rep. N.Y. St.

Mus. 43:85. 1890.

Butyriboletus fechtneri (Velenovsky) D. Arora & J. L.Frank, comb. nov.

MycoBank MB803320; Boletus fechtneri Velenovsky, Ceske Houby 4–5: 704. 1922.

Butyriboletus pseudoregius (Huber) D. Arora &J.L.Frank, comb. et stat. nov.

MycoBank MB804787; Boletus appendiculatus subsp. pseudoregius Huber, Z.

Pilzk. 17:87. 1938.

Butyriboletus regius (Krombholz) D. Arora & J. L.Frank, comb. nov.

MycoBank MB803323; Boletus regius Krombholz, Naturgetr. Abbild. Beschr.

Schwamme (Prague) 2:3. 1832.

466 MYCOLOGIA

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ARORA AND FRANK: BOLETES CLARIFIED 467

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468 MYCOLOGIA

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ARORA AND FRANK: BOLETES CLARIFIED 469

Butyriboletus roseoflavus (Hai B. Li & Hai L.Wei) D.Arora & J.L. Frank., comb. nov.

MycoBank MB804788; Boletus roseoflavus Hai B. Li & Hai L. Wei, Mycol Prog

2013.01.24

Butyriboletus subappendiculatus (Dermek, Lazebnicek& Veselsky) D. Arora & J. L. Frank, comb. nov.

MycoBank MB803326; Boletus subappendiculatus Dermek, Lazebn. & J. Veselsky,

Fungorum Rariorum Icones Coloratae 9:13. 1979.

Although Assyov (2012) published Boletus fuscor-oseus Smotlacha as an earlier synonym for B.pseudoregius Hubert ex Estades, we recombined thelatter name because it is better understood. It islikely that other Boletus species (e.g. Boletuspulchriceps E.E. Both, A.E. Bessette & R. Chapman)will be transferred to Butyriboletus (see Nuhn et al.2013).

The following six species are newly described;regional identification keys are provided after thedescriptions.

FIG. 1. ML tree illustrating phylogenetic relationships of species in the new genus Butyriboletus inferred from ITS nrDNAusing fastDNAml. Tree topology corresponds to the optimal ML tree. Bootstrap values (. 50%) from the parsimony analysis(1000 replicates) using PAUP* are above branches.

470 MYCOLOGIA

Butyriboletus persolidus D.Arora & J.L. Frank, sp.nov. FIG. 3AMedium-sized to large basidiocarps with brown

pileus, yellow tube layer that usually turns blue whenbruised, yellow reticulate stalk and firm, mild-tastingflesh that may turn blue erratically when exposed.Spores fusoid. Fruiting with oaks, typically in the fall.

MycoBank MB803208Holotype: USA, California, Santa Cruz County,

Henry Cowell Redwoods State Park, 37.02618,2122.03884, in a nearly pure stand of Quercusagrifolia, 1 Nov 2011, Arora11103 (SFSU).5 Boletus appendiculatus sensu Thiers, California Mush-

rooms: A Field Guide to the Boletes: 41 (1975)

FIG. 2. Maximum likelihood tree generated in MEGA 5 with LSU nrDNA, showing the new genus Butyriboletus separatefrom the core group of Boletus s. str. The tree with the highest log likelihood is shown. Bootstrap values (. 50%) from theparsimony analysis (1000 replicates) using PAUP* are above branches.

ARORA AND FRANK: BOLETES CLARIFIED 471

FIG. 3. A. Butyriboletus persolidus (Arora11103). B. Bu. primiregius (Arora11084). C. Bu. autumniregius (Arora11095).D. Bu. querciregius (Arora11100). E. Bu. querciregius (Arora11098). F. Bu. sanicibus (Arora99211). G. Bu. yicibus (Arora9727).

472 MYCOLOGIA

Additional photos: Arora (1986): color plate 134;Arora (1991):163.

Etymology: per (L.) 5 very; solidus (L.) 5 solid or dense.

Pileus 8–25(30) cm broad, convex becomingbroadly so at maturity or sometimes plane; surfacedry or sightly tacky to the touch but not viscid,glabrous but typically with a fine, pallid bloom whenyoung; mostly tan to brown, but at times cinnamon-brown and at other times yellowish brown to buff,

sometimes with darker rusty brown blushes. Contextfirm and dense, thick, pale yellow, typically unchang-ing in the button stage but with age usually turningblue at least somewhat when cut (often slowly anderratically but more dramatically in older specimens);flavor mild.

Hymenophore (tube layer) pale yellow becomingbright yellow and eventually olive yellow; pore surfaceusually concolorous with the tubes (rarely slightly

FIG. 4. A. Butyriboletus primiregius in California market. B. Bu. abieticola with distinctive fibrillose scales (JLF2564, photo byNoah Siegel). C. Yi women with Bu. yicibus and Lactarius sp. D. Bu. roseoflavus on Kunming street, Yunnan, China.

ARORA AND FRANK: BOLETES CLARIFIED 473

reddish), typically turning blue quickly when bruisedexcept in the button stage; tubes at first short inrelation to the pileus context, but 1–2 cm or longerwhen mature; individual pores typically less than 1 mmbroad.

Stipe 5–15(25) cm long, 3–7 cm thick at the apex,usually clavate or bulbous when young but oftenequal or with a slightly tapered base when mature;surface butter-yellow to bright yellow throughout,although sometimes also with brownish or reddishstains especially downward; finely reticulate over atleast the upper portion, the reticulation yellow butoften becoming brownish after spores are shed.Context firm, yellow except for the base, whichusually has a distinct vinaceous tinge, turning blueonly slightly or not at all when cut.

Spores dark olive brown in mass, 12–15 3 4–5 mm(Q 5 3.2, n 5 30), subfusoid, thin-walled, smooth,pale brown or yellowish in KOH. Basidia clavate, four-spored; hymenial cystidia fusoid-ventricose. Pileuscuticle an interwoven trichodermium with few if anyerect hyphal tips.

Specimens examined: USA, CALIFORNIA: Santa CruzCounty, Henry Cowell Redwoods State Park, in a nearlypure stand of Quercus agrifolia, 1 Nov 2011, Arora11103(Holotype: SFSU, Isotype: OSC148241). Santa Cruz County:Arora027 (SFSU, OSC), Arora11101 (SFSU), Arora11102(SFSU, OSC); Amador County, Arora11109 (SFSU, OSC),Arora11110 (SFSU, OSC); San Mateo County, Halling15(SFSU), HDT10943 (SFSU).

Occurence: Solitary or in groups in soil underhardwoods or in mixed forests, usually associated withlive oak (e.g. Quercus agrifolia), probably also with otherfagaceous trees (e.g. Notholithocarpus densiflorus, Chry-solepis chrysophylla); typically fruiting Oct–Dec andsometimes prolific after the first fall rains. So far verifiedonly from California, occurring in both the coastalregion and in the Sierra Nevada foothills. Reports ofBoletus appendiculatus sensu Thiers under conifers inthe Pacific Northwest (e.g. Tylutki 1987) appear to bemisidentifications based on Butyriboletus abieticola, Bu.primiregius and/or Bu. autumniregius. However, reportsof Boletus appendiculatus with Q. garryana on Vancou-ver Island, British Columbia, are likely based on eitherthis species and/or Bu. querciregius.

Comments: This species is remarkable even amongbutter boletes for its thick, dense flesh. The capsometimes has rusty brown areas but lacks the rose,pink or vinaceous tints of other California butterboletes. It is most likely to be mistaken for Bu.querciregius, which also is associated with oaks. Thelatter has a distinctly reddish pileus when fresh butfaded specimens can approach color of Bu. persolidus.Bu. querciregius, however, tends to be softer than Bu.persolidus and is much more likely to have blushes ofred on the stipe (although not consistently). Also, its

pileus is often blotched with yellow or pink while thatof Bu. persolidus tends to remain evenly brown.

Butyriboletus primiregius D. Arora & J.L. Frank, sp.nov. FIGS. 3B, 4AMedium-sized to large basidiocarps with reddish or

vinaceous pileus fading to brown or olive, yellow tubelayer that usually turns blue when bruised, yellowreticulate stalk and firm, mild-flavored flesh that mayturn blue erratically when exposed. Spores fusoid.Fruiting under mountain conifers, typically in late spring.

MycoBank MB803209Holotype: USA, California, Siskiyou County: 5 mi E.

of McCloud, 41.28788, 2122.07308, under Abies, 26Jun 2011, JLF2030 (SFSU).

Etymology: primi (L.) 5 first, because it is the first of the

butter boletes to appear each year in western USA mountains;

regius (L.) 5 kingly, a reflection of its market name (king butter

bolete) but also referring to its European relative, B. regius.

Pileus 8–25(30) cm broad, convex, becomingbroadly convex at maturity or at times plane orundulating; surface dry or sightly tacky to the touchbut not viscid; glabrous or breaking up to form manyscales (but these much smaller than in Bu. abieticola);color at first wholly or mostly dark red or vinaceous red(but color often obscured by a layer of brown dust),often developing dingy brown, tan, ocher-brown ordingy olive brown tones as it ages or is exposed to light;the vinaceous red tints sometimes disappearing entire-ly or more often remaining visible at least near themargin. Context firm and dense, thick, pale yellow,typically unchanging in the button stage but atmaturity usually turning blue at least somewhat whencut (often slowly and erratically and most pronouncedjust above the tube layer); flavor mild.

Hymenophore (tube layer) pale yellow becomingbright yellow and eventually olive yellow or greenish;pore surface usually concolorous with the tubes,typically turning blue quickly when bruised except inthe button stage; tubes at first short in relation to thepileus context, but 1–2 cm or longer when mature;individual pores typically less than 1 mm broad.

Stipe 5–15(25) cm long, 2–7 cm thick at the apex,usually clavate or bulbous when young but oftenbecoming more or less equal with age; surface butteryellow to bright yellow throughout or commonly withdark red (rhubarb red) stains toward the base, oftenbruising blue when touched or rubbed; finelyreticulate over at least the upper portion, thereticulation yellow but often becoming brownish afterspores are shed, rarely reddish; base often terminat-ing in one or more rootlike processes originatingdeep in the soil. Context firm, yellow except for the

474 MYCOLOGIA

base, which usually has a distinct vinaceous tinge, notturning blue or turning blue only slightly when cutbut larval tunnels often rhubarb red.

Spores dark olive brown in mass, (12)13–17(18) 3

3.5–5 mm (Q 5 3.5, n 5 30); fusoid, thin-walled,smooth, pale brown or yellowish in KOH. Basidiaclavate, four-spored; hymenial cystidia fusoid-ventri-cose. Pileus cuticle an interwoven trichodermiumwith few if any erect hyphal tips.

Specimens examined: USA, CALIFORNIA: Siskiyou Coun-ty, 5 mi E. of McCloud, under Abies, 26 Jun 2011, JLF2030(Holotype: SFSU, Isotype: OSC148242). El Dorado County,Arora11081 (SFSU, OSC), Arora11084 (SFSU, OSC),Arora11085 (SFSU, OSC); Sierra County, HDT47714(SFSU); Siskiyou County, DBB00606 (OSC), JLF1973(OSC), JLF2029 (OSC); IDAHO: Pearl Creek, UpperPayette Lake, Valley County, AHS69419 (SFSU); OREGON:Jackson County, JLF2097 (OSC), JLF2139 (OSC).

Occurence: Solitary or in groups in soil underconifers, fruiting in the late spring and early summer(May–Jul). It is associated primarily with Abies spp. at4000–7000 feet, but DBB00606 was found at 2800 feetin an oak forest with scattered conifers. It is the first ofthe butter boletes to appear each year, typicallyfruiting close on the heels of Boletus rex-veris D.Arora & Simonini and at least 2 wk before Butyri-boletus abieticola (Thiers) D. Arora & J.L. Frank. It iscommon in the Sierra Nevada of California and theMount Shasta region and also occurs in the moun-tains of Oregon and Idaho. It is absent from thecoastal region as far as is known.

Comments: This species can be distinguished fromclose relatives by its late spring fruiting season and thepronounced tendency of the cap to fade to dingyolive brown or paler when it is exposed to sunlight.The scales on the cap, if present, are smaller than inBu. abieticola and not obviously fibrillose. In theMount Shasta area of northern California, where thetype collection was made, this species is harvestedcommercially for sale to select markets and restau-rants in USA, usually under the name King ButterBolete (FIG. 4A).

Butyriboletus autumniregius D. Arora & J.L. Frank, sp.nov. FIG. 3CMedium-sized to large basidiocarps with reddish to

vinaceous pileus, yellow tube layer that usually turnsblue when bruised, yellow reticulate stalk and firm,mild-flavored flesh that may turn blue erratically whenexposed. Spores fusoid. Fruiting in the fall in mixedwoods and under conifers.

MycoBank MB803210Holotype: USA, California: Mendocino County,

Anchor Bay, 38.80983, 2123.5693, in a forest of

Douglas-fir (Pseudotsuga menziesii) and redwood, 15Nov 2011, Arora11112 (SFSU).

Etymology: autumni (L.) 5 autumn, for its autumn

fruiting habit; regius (L.) 5 kingly, and also refers to its

European relative, B. regius.

Pileus 8–30 cm broad, convex becoming broadlyconvex at maturity or sometimes plane; surface dry orsightly tacky to the touch but not viscid; glabrous orbreaking up to form many small scales (but thesetypically smaller than in Bu. abieticola); color whollyor mostly rose red to vinaceous red or at timesmottled with tan or yellow. Context firm and dense,thick, pale yellow, typically unchanging in the buttonstage but in age usually turning blue at least somewhatwhen cut (often slowly and erratically); flavor mild.

Hymenophore (tube layer) pale yellow becomingbright yellow and eventually olive yellow or greenish;pore surface usually concolorous with the tubes,typically turning blue quickly when bruised exceptin the button stage; tubes at first short in relation tothe pileus context but 1–2.5 cm or longer whenmature; individual pores typically less than 1 mmbroad.

Stipe 5–15(25) cm long, 3–7 cm thick at the apex,usually clavate and sometimes markedly bulbouswhen young but often less so (at times equal) withage; surface butter yellow to bright yellow throughoutor commonly with dark red (rhubarb red) stainstoward the base, often bruising blue when touched orrubbed; finely reticulate over at least the upperportion, the reticulation yellow or occasionally red-dish but often becoming brown after spores are shed.Context firm, pale yellow except for the base, whichusually has a distinct vinaceous tinge, turning blueslightly or not at all when cut.

Spores dark olive brown in mass, fusoid, thin-walled, smooth, pale brown or yellowish in KOH,(12)13–16.5(18) 3 4–5 mm (Q 5 3.5, n 5 30). Basidiaclavate, four-spored; hymenial cystidia fusoid-ventri-cose. Pileus cuticle an interwoven trichodermiumwith few erect hyphal tips.

Specimens examined: USA, CALIFORNIA: MendocinoCounty, near Anchor Bay in a forest of Douglas-fir(Pseudotsuga menziesii) and redwood, 15 Nov 2011,Arora11112 (Holotype: SFSU, Isotype: OSC148243). Hum-boldt County, Arora11114 (SFSU); Mendocino County,Arora11113 (SFSU, OSC), HDT43782 (SFSU, OSC);Plumas County, Arora11095 (SFSU, OSC), Arora11096(SFSU, OSC); San Mateo County, Arora11108 (SFSU,OSC). OREGON: Benton County: ARI063 (OSC); JacksonCounty, JDS289 (OSC); Josephine County, JLF2271 (SFSU,OSC), JLF2275 (OSC); Lane County, OSC66191 (OSC).

Occurence: Solitary or in groups on ground incoastal forests as well as mid-elevation forests of theSierra Nevada and Cascades; associated with conifersand possibly also with hardwoods. Most of our

ARORA AND FRANK: BOLETES CLARIFIED 475

collections were made in mixed woods, makingidentification of the mycorrhizal host speculative,but the type collection likely was associated withDouglas-fir (Pseudotsuga menziesii) in that there wereno other ectomycorrhizal tree hosts in the area; also,this species has been observed in pure stands ofsecond-growth Douglas-fir. Other possible but unver-ified tree hosts for this species (based on othercollections) include spruce (Picea engelmannii),tanoak (Notholithocarpus densiflorus), madrone (Ar-butus menziesii), fir (Abies spp.) and pine (Pinusspp.). Fruiting generally in the fall (Sep–Dec). Thisspecies is fairly common from the central Californiacoastal region northward and also at low to mid-elevations in the Sierra Nevada, Siskiyous andCascades; its northern limit has not been determinedbut at least one of its hosts, Douglas-fir, extends intoBritish Columbia, Canada.

Comments: This species is best distinguished fromBu. primiregius by its fall fruiting season. Its cap doesnot tend to fade as much as that species but this maybe a function of growing in more humid conditionsthan any inherent difference in pigment stability.From Bu. querciregius it differs in habitat (it has notbeen found to form mycorrhizal associations withQuercus) and more vivid pileus color (tending towarddeep rose red or vinaceous red when fresh ratherthan pinkish red, pinkish brown or yellowish) and inits longer spores with larger Q ratio.

Butyriboletus querciregius D. Arora & J.L. Frank, sp.nov. FIG. 3D, EMedium-sized to large basidiocarps with reddish or

yellow-tinged pileus, yellow tube layer that usuallyturns blue when bruised, yellow reticulate stalk andfirm, mild-flavored flesh that may turn blue erraticallywhen exposed. Spores short-fusoid. Fruiting in fallwith oaks.

MycoBank MB803211Holotype: USA, California, Santa Cruz County: near

Aptos, 36.96860, 2121.84540, under coast live oak(Quercus agrifolia), 31 Oct 2011, Arora11100 (SFSU).

Additional photos: Arora (1986): color plate 133 (asBoletus regius).

Etymology: querci (L.) 5 pertaining to oak; regius (L.) 5

kingly, and also refers to its European relative, B. regius.

Pileus 6–20(25) cm broad, convex becomingbroadly convex at maturity or sometimes plane;surface dry or sightly tacky to the touch but notviscid; glabrous or occasionally breaking up to formsome small scales; reddish or dull red when youngand fresh or yellow overlain with red (i.e. reddishorange overall with more yellow at the margin) or red

blotched with yellow but often fading to pale reddishbrown, pinkish tan, yellow or yellowish buff with ageor where exposed to light. Context firm, thick, paleyellow, typically unchanging in the button stage butwith age usually turning blue at least somewhat whencut; flavor mild.

Hymenophore (tube layer) pale yellow becomingbright yellow and eventually olive yellow or greenish;pore surface usually concolorous with the tubes,typically turning blue quickly when bruised exceptin the button stage; tubes at first short in relation tothe pileus context but 1–2 cm or longer when mature;individual pores typically less than 1 mm broad.

Stipe 5215(20) cm long, 2–6 cm thick at the apex,usually clavate or slightly bulbous when young butoften more or less equal in age; surface butter yellowto bright yellow throughout or with beautiful red todark red blushes toward the base, sometimes bruisingblue when pressed but variable in this respect; finelyreticulate over at least the upper portion, thereticulation yellow or occasionally reddish but oftenbecoming brown after spores are shed. Context firm,pale yellow except for the base, which usually has adistinct vinaceous tinge, turning blue little if at allwhen cut.

Spores dark olive brown in mass, fusoid, thin-walled, smooth, pale brown or yellowish in KOH,(10)11–15(16) 3 3.5–5 mm (Q 5 3.0, n 5 30). Basidiaclavate, four–spored; hymenial cystidia mostly fusoid-ventricose. Pileus cuticle an interwoven trichoder-mium with few erect hyphal tips.

Specimens examined: USA, CALIFORNIA: Santa CruzCounty, near Aptos under coast live oak (Quercus agrifolia),coll. by F. Menge, 31 Oct 2011, Arora11100 (Holotype:SFSU, Isotype: OSC148244). Santa Cruz County, Ar-ora11097 (SFSU), Arora11098 (SFSU, OSC), Arora11099(SFSU, OSC), Arora11106 (SFSU). Sonoma County, SantaRosa, Arora12012 (SFSU). WASHINGTON: Klickitat Coun-ty, 01MWB052012 (OSC), 01MWB120512 (OSC).

Occurence: Solitary or in groups in leaf litter underoaks (mainly Q. agrifolia and Q. garryana, lesscommonly with Q. lobata and other Quercus spp.). Itfruits mostly in the fall (Sep–Dec), but the first of theWashington collections listed above was made in Mayand DA has found it in coastal California in June. It ispossible that this species also occurs with tanoak, butsuch a relationship has not been verified. It iscommon after early fall rains in the oak woodlandsof California, infrequent northward to Washingtonand possibly British Columbia. We were able toidentify an ITS DNA sequence in GenBank(EU018562) of an ectomycorrhizal root tip from Q.garryana in Oregon as Bu. querciregius (FIG. 1); itsbasic ectomycorrhizal morphology is tan, monopodialand tortuous (Moser et al. 2009). The distributionand tree host preferences of this species appear to

476 MYCOLOGIA

closely parallel those of the oak-associated populationof Boletus barrowsii Thiers & Smith (Arora 2008).

Comments: This is the third species, along with Bu.primiregius and Bu. autumniregius, encompassed byThiers’ (1975) concept of Boletus regius. The latterspecies, however, turns blue only rarely when cut andhas not been verified to occur in North America. Bu.querciregius is most likely to be confused with Bu.autumniregius in that both species fruit in the fall andtheir ranges overlap. Bu. querciregius differs in itsmycorrhizal host, shorter spores with smaller Q ratio,and also by its different pileus color: red or dull red oreven orange-red, sometimes blotched with yellowbefore fading to pinkish brown, tan or yellowish. Bu.querciregius also can be mistaken for Bu. persolidus (seecomments under that species for a comparison). Somecollections of Bu. querciregius feature a beautiful blushof red over the lower portion of the stipe as shown incolor plate 133 of Arora (1986), but this is not aconsistent character. It is worth noting that Ar-ora11097 grew under the same tree as the specimensArora (1986) photographed 30 y earlier.

Butyriboletus yicibus D. Arora & J.L. Frank, sp. nov.FIGS. 3F, 4C

Medium-sized basidiocarps with brown pileus,yellow tube layer that usually stains blue-gray whenbruised, slender yellow reticulate stalk and firm, mild-flavored flesh that may stain blue-gray erratically whenexposed. Spores fusoid or subfusoid. Fruiting insummer in pine forests and mixed woods.

MycoBank MB803256Holotype: China, Yunnan, Lijiang County, 26.9947,

100.2524, scattered in pine forest (Pinus yunnanen-sis) on the road from Lijiang to Jade Dragon SnowMountain, 3 Aug 1997, Arora9727 (SFSU).

Etymology: Yi 5 the largest ethnic minority in Yunnan;

cibus (L.) 5 food.

Pileus 6–15 cm broad, with an incurved marginbecoming broadly convex; surface predominantly dullbrown, sometimes with reddish brown areas, glabrous,not viscid. Context thick, firm, pale yellow, turningblue slightly and erratically when cut, at least in mostspecimens; odor and flavor mild.

Hymenophore (tube layer) pale yellow when fresh,becoming greenish yellow with age, the pore surfacetypically bruising bluish (blue-gray) when rubbed, butthe staining may be absent in buttons; tubes relativelyshort for a long time but eventually 2 cm long ormore, typically depressed around the stipe; poressmall (, 1 mm).

Stipe relatively long and slender, 2–4 cm thick atapex and 10–20 cm long, equal or swollen at the base,

predominantly pale yellow or yellowish buff whenfresh but often brownish stained below; surface oftenstaining bluish gray when pressed or rubbed; upperportion finely reticulate. Context yellow, brighteryellow toward the base and with or without avinaceous tinge at the extreme base; turning bluelittle if at all when cut.

Spores dark olive brown in mass, fusoid, thin-walled, smooth, pale brown or yellowish in KOH,(11)12–15(16) 3 3.5–5 mm (Q 5 3.3, n 5 30). Basidiaclavate, four-spored, hymenial cystidia mostly fusoid-ventricose. Pileus cuticle an interwoven trichoder-mium.

Specimens examined: CHINA, YUNNAN: Lijiang County,scattered in pine forest on the road from Lijiang to JadeDragon Snow Mountain, 3 Aug 1997, Arora9727 (Holotype:SFSU, Isotype: OSC148246).

Occurence: Scattered on ground in pine forest(Pinus yunnanensis); fruiting in the summer (Jul–Sep). Verified from Lijiang County, Yunnan, butobserved in adjacent areas and probably more widelydistributed.

Comments: This species can be distinguished fromBu. sanicibus by its leggy, more gracile stature andtendency to stain blue-gray rather than blue whenbruised, and both species differ from Bu. roseoflavusin lacking red tones in the pileus. Bu. yicibus is eatenby the Yi minority of Lijiang and probably by otherminorities such as the Naxi and Bai. DA encounteredit several times while conducting research in Yunnan,but only the type collection was examined for thisstudy.

Butyriboletus sanicibus D. Arora & J.L. Frank, sp. nov.FIG. 3G

Medium-sized to fairly large basidiocarps withbrown pileus, yellow tube layer that usually turns bluewhen bruised, thick, yellow reticulate stalk and firm,mild-flavored flesh that usually turns blue whenexposed. Spores fusoid or subfusoid. Fruiting insummer in pine forests and mixed woods.

MycoBank MB803257Holotype: China, Yunnan, Shilin County, 24.76972,

103.34972, scattered in pine forest (Pinus yunnanen-sis) in Sani village near the Stone Forest, 4 Jul 1999,Arora99211 (SFSU).

Etymology: Sani 5 an ethnic minority especially numer-

ous to the east of Kunming, Yunnan; cibus (L.) 5 food.

Pileus 7220 cm broad, with an incurved marginbecoming broadly convex; surface predominantly dullbrown, in young specimens often overlaid with a pallidsheen, not viscid. Context thick, firm, pale yellow,normally turning blue when cut; odor and flavor mild.

ARORA AND FRANK: BOLETES CLARIFIED 477

Hymenophore (tube layer) pale yellow becomingbright yellow, slightly greenish with age, typicallybruising blue when rubbed, but the staining maybe absent in buttons; tubes relatively short for along time but eventually 2 cm long or more,typically depressed around the stipe; pores small(, 1 mm).

Stipe relatively robust, 2.5 cm or more thick, equal orsomewhat clavate, typically pale yellow when fresh andturning blue when bruised (but some variationobserved according to how wet or dry the mushroomis), finely reticulate at least over the upper portion.Context pale yellow, typically turning blue only slightlyif at all when cut (in contrast to the pileus context),typically with a vinaceous tinge in the basal area.

Spores dark olive brown in mass, subfusoid, thin-walled, smooth, pale brown or yellowish in KOH,11215 3 425 mm (Q 5 2.8, n 5 30). Basidia clavate,four-spored; hymenial cystidia mostly fusoid-ventri-cose. Pileus cuticle an interwoven trichodermium.

Specimens examined: CHINA, YUNNAN: Shilin County,scattered in mixed forest with pines present (Pinusyunnanensis) outside a Sani village near the Stone Forest,4 Jul 1999, Arora99211 (Holotype: SFSU, Isotype:OSC148247). Lijiang County, Arora9726.

Occurence: Scattered on ground in pine forests(Pinus yunnanensis) or mixed woods; fruiting insummer (Jun–Sep). Known from Shilin and Lijiangcounties in Yunnan and likely occurring throughmuch of mid-elevation Yunnan.

Comments: This species is more robust than Bu.yicibus and is phenotypically reminiscent of theEuropean species, Bu. appendiculatus and Bu.fechtneri. Indeed, it is closely related to the latter(FIGS. 1, 2). This species is commonly eaten by Sanipeople in Shilin County, Yunnan. It is occasionallyseen in farmers’ markets but not in the abundantquantities typical of the pallid- or reddish cappedspecies, Bu. roseoflavus.

To enable identification in the field, separatedichotomous keys are provided for the Butyriboletusspecies of western USA and Yunnan, China. Only onespecies, Bu. brunneus, has been identified fromeastern North America. For a key to Europeanspecies, see Assyov (2012).

KEY TO BUTYRIBOLETUS SPECIES OF CALIFORNIA, OREGON,WASHINGTON AND IDAHO, USA

1. Pileus at least partly (often entirely) pink, red, rose orvinaceous when fresh (but may fade with age) . . . . 2

1. Pileus without pink, red, rose or vinaceous tones . . . 52. Pileus with fibrillose scales at maturity; associ-

ated with conifers, especially fir . . Bu. abieticola2. Pileus not as above (if surface breaks up into

scales when mature then the scales not

fibrillose); associated with hardwoods or coni-fers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3. Pileus reddish to pinkish; spores mostly 11–15 mmlong with a Q ratio of 3; associated primarily if notexclusively with oaks . . . . . . . . . . . Bu. querciregius

3. Pileus typically vinaceous to deep rose when fresh;spores mostly 13–17 um long with a Q-ratio of 3.5;associated primarily with conifers but possibly alsowith oaks and tanoaks . . . . . . . . . . . . . . . . . . . . . 44. Fruiting in late spring-early summer (May–Jul)

in mountains . . . . . . . . . . . . . Bu. primiregius4. Fruiting in fall (Sep–Dec) in mountains as well

as lowlands . . . . . . . . . . . . . Bu. autumniregius5. Pileus appressed fibrillose or slightly felt-like when

young and breaking up into fibrillose scales bymaturity; associated with conifers . . . . Bu. abieticola

5. Not as above; associated with hardwoods, especiallyoak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66. Pileus some shade of brown; stipe typically

without red tones . . . . . . . . . . . Bu. persolidus6. Pileus yellow or yellowish; stipe sometimes with

red tones . . . . . . . . . . . . . . . . . . Bu. querciregius

KEY TO BUTYRIBOLETUS SPECIES OF YUNNAN, CHINA

1. Pileus whitish to slightly yellowish to pink or darkred but not brown . . . . . . . . . . . . . Bu. roseoflavus

1. Pileus some shade of brown . . . . . . . . . . . . . . . . 22. Stipe typically longer than width of pileus;

pore and stipe surfaces typically stainingbluish gray when bruised . . . . . . . Bu. yicibus

2. Stipe typically as long as or shorter than width ofpileus; pore and stipe surfaces typically stainingblue or blue-green when bruised . . Bu. sanicibus

DISCUSSION

North American, Chinese and European butter boletesform a new monophyletic genus, Butyriboletus, contain-ing at least 14 taxa (FIGS. 1, 2). In most cases these taxacan be distinguished by their geographic location,habitat, fruiting season and traditional field characterssuch as pileus color and staining reactions. Micromor-phology is not particularly helpful in Butyriboletus: Taxaexamined by the authors have similar basidia, hymenialcystidia, an epicuticular trichodermium and smooth,long-ellipsoid to fusoid (‘‘boletoid’’) spores.

Five species of Butyriboletus occur in western USA:Bu. abieticola Thiers plus four newly describedspecies. Three of the newly described species (Bu.autumniregius, Bu. primiregius, Bu. querciregius) havea reddish pileus when fresh. Together they compriseThiers’ (1975) concept of Boletus regius, while thefourth new species, Bu. persolidus, has a brown pileusand corresponds with Thiers’ (1975) concept ofBoletus appendiculatus. Our ITS data (FIG. 1) show

478 MYCOLOGIA

that Bu. primiregius and Bu. autumniregius have theclosest affinity to each other and to Bu. querciregius.

Three of the five western USA species are widelydistributed and associated primarily with Pinaceae(Bu. abieticola, Bu. autumniregius, Bu. primiregius),while two associate primarily with Fagaceae (Bu.persolidus, Bu. querciregius). Of the conifer-dwellingspecies, Bu. autumniregius and Bu. primiregius can bedistinguished by fruiting season: generally May–Jul forBu. primiregius versus Sep–Dec for Bu. autumniregius.Bu. abieticola Thiers generally fruits from July untilearly October and may overlap temporally with eitherof the previous species but consistently showsfibrillose scales on the mature pileus (FIG. 4B).

In addition to growing in pure conifer stands, Bu.autumniregius frequently occurs in mixed forestswhere its ectomycorrhizal host is speculative. Theoak-associated Bu. querciregius fruits at the same timeas Bu. autumniregius but differs in pileus color andby shorter spores. The other oak-associated species,Bu. persolidus, is easily distinguished by its brownpileus.

The five classic butter boletes of Europe andnorthern Africa as described by Assyov (2012), Boletusappendiculatus, Bu. fechtneri, Bu. fuscoroseus (5 Bu.pseudoregius), B. regius and B. subappendiculatus,were found to nest within Butyriboletus (FIGS. 1, 2).Our results show no overlap in the occurrence ofbutter bolete species among North America andEurope or China. A close affinity between Bu.sanicibus (China) and Bu. fechtneri (Europe) wassupported by both ITS and LSU data (FIGS. 1, 2).

One bolete from eastern USA, Butyriboletus brun-neus (; Boletus speciosus var. brunneus Peck), alsofalls clearly within the butter bolete clade. We wereunable to locate any recent collections of the typicalvariety of Boletus speciosus Frost, described as having a‘‘scarlet lake red’’ pileus (Frost 1874); therefore weraised var. brunneus to species rank in the newcombination. Most of the Boletus speciosus collectionsfrom Tennessee sequenced by Li et al. (2013) have ITSdata identical to that which we obtained from severalcollections of Boletus roseopurpureus Both, A.E.Bes-sette, & Roody (Bessette et al. 2000). B. roseopurpureusis an outlier to Butyriboletus, according to our data.Other than B. roseopurpureus, the closest relatives toButyriboletus are Boletus frostii J.L. Russell and Boletusfloridanus (Singer) Murrill, two distinctive boletes withraised reticulation on the stalk and reddish poresurface beaded with golden droplets when young. Athird species from eastern USA, Boletus auripes Peck,was placed in sect. Appendiculati by Snell and Dick(1970) but was found to have different affinities(FIGS. 1, 2). As a result it remains in the residual poolof Boletus s.l. species awaiting future reassignment.

As for the two newly described species fromYunnan, both are associated primarily (althoughperhaps not exclusively) with pine. Both are eatenlocally (FIG. 4C) and occasionally sold in farmers’markets but are not nearly as prevalent or aseconomically valuable as the recently described Bu.roseoflavus (FIG. 4D). The pileus of that species isoften reddish or pinkish as described by Li et al.(2013), but in our Yunnan collections is frequentlypallid as well but not brown.

Our study of the butter boletes was not intended tobe exhaustive. Given the geographical breadth andgreat biological diversity of China it is likely thatadditional unrecognized species of Butyriboletus occurthere. We did not include Japanese taxa in this study(see Boletus regius sensu Hongo 1960 and B. speciosussensu Imazeki et al. 1988). Butter boletes also havebeen reported from the highlands of Mexico underthe names Boletus regius and B. appendiculatus(Guzman 1997). Boletus pulchriceps E.E. Both, A.E.Bessette & R. Chapman (Bessette et al. 2000),described as occurring with oak in southern Arizona,has the aspect of other butter boletes and belongs tothe ‘‘regius clade’’ according to Nuhn et al. (2013).Additional unsequenced taxa from eastern NorthAmerica also may belong to Butyriboletus.

ACKNOWLEDGMENTS

We are extremely grateful for the help of those who providedvoucher collections for our study: John Banks, Michael Beug,Dimitar Bojantchev, Herman Brown, Matteo Gelardi, JeanneJackson, Nicholas Janson, Louis Jeandin, Freddie Menge, AlijaMujic, Pavel Nedelev, Jay Scelza, Noah Siegel, Hugh Smith,Wendy So, Andy Taylor, Dave Wasilewski, and Zhu Gui Feng.We thank Dr Dennis Desjardin of San Francisco StateUniversity and Dr Joey Spatafora of Oregon State Universityfor facilitating our study of herbarium collections and Dr WangXianghua of the Kunming Institute of Botany for her assistancethere. Dr Shaun Pennycook provided valuable nomenclaturalguidance. We thank Dr David Oline of Southern OregonUniversity for helpful discussions regarding phylogeneticanalyses, Dr James Trappe for his assistance in helping tochoose Latin names, and Dimitar Bojantchev, Dr Tom Bruns,and Dr Matthew Smith for making valuable suggestions and forreviewing the manuscript before publication.

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