Reprinted from MYCOLOGIA, Vol. LXIV, No, 6, pp. 1258-1269, Nov.-Dec., 1972 Printed in U.S.A. PHELLINUS TORULOSUS IN NORTH AMERICA1 R. L. GILBERTSON Department of Plant Pathology, University of Arizona, Tucson 85721 AND H. H. BURDSALL, JR. Center for Forest Mycology Research, U.S. Forest Service, Madison, Wisconsin 53705 SUMMARY Phellinus torulosus (Pers.) Bourd. et Galz. has been found in two mountain ranges in southeastern Arizona. It occurs at elevations of 8,000 ft or above, mostly on southwestern white pine (Pinus strobiformis Engelm.) in which it causes a white pocket rot of the roots. It is clearly distinct from Phellinus gilvus (Schw.) Pat., with which it has been con- fused in the past. The fungi currently placed in the genus Phellinus Quél, are ligni- colous Hymenomycetes in the order Aphyllophorales. They are char- acterized by perennial basidiocarps with the hymenophore in the form of united tubes and borwn context tissue that permanently darkens to black in KOH solution (xanthochroic reaction). Setae are present in the hymenium of some specids and basidiospores are hyaline or pig- mented. The hyphae lack clamp connections. The species of Phellinus are all associated with white rots and in culture typically give a posi- tive oxidase reaction on tannic and gallic acid media or with gum guaiac solution. In older taxonomic works the species now placed in Phellinus are found in the genera Fomes (Fr.) Kickx and Poria (Pers.) S. F. Gray of the Polyporaceae sensu lato. In current systems of classifica- tion Phellinus is placed in the family Hymenochaetaceae Donk. Persoon first described Polyporus torulosus from Europe in 1825, and the transfer to Phellinus was made by Bourdot and Galzin in 1925. The combination Fomes torulosus (Pers.) Lloyd is also well established 1 The University of Arizona Agricultural Experiment Station journal article No. 1858. 1259 MYCOLOGIA, VOL. 64, 1972 in the literature. The fungus is well known in Europe, and has been reported to be widely distributed on many species of woody angiosperms and some conifers in the warmer regions of western and southern Europe, the USSR, and Japan (see Bourdot and Galzin, 1928; Pilát, 1936 ; Bondarzew, 1953; Domanski' et al., 1967 ; Jahn, 1967 ; Ito, 1955). Most of these publications state that P. torulosus occurs in North America. These records are apparently based on reports by C. G. Lloyd of P. torulosus from North American localities. Phellinus torulosus was first reported to occur in North America by Lloyd in 1910. The collection on which this report is based was made from the trunk of a live oak in Audubon Park, New Orelans, La., by C. W. Edgerton. We have examined the specimen (CGL Herb. No. 42835) and consider it to be a basidiocarp of Phellinus gilvus (Schw.) Pat. Lloyd later (1924) reported an additional North American col- lection from Florida (CGL Herb. No. 23919). We also believe this specimen should be referred to P. gilvus. Overholts (1953) recognized P. torulosus as occurring in North America on the basis of the speci- mens identified as such in the Lloyd Herbarium, but stated that the specimens were “a thick form of P. licnoides.” Polyporus licnoides Mont. is considered to be conspecific with (Lloyd, 1915a, b) or very similar to P. gilvus (Overholts, 1953; Lowe and Gilbertson, 1961). We agree with Lloyd in believing the two are conspecific and consider P. licnoides to be a synonym of P. gilvus. Overholts (1953) also cites additional specimens of P. torulosus on Sassafras from St. Louis, Mo. We have examined these (CGL 35796 and 36027) and consider them to be P. gilvus also, As far as we can determine, therefore, these previous reports of P. torulosus in North America are all incorrect. Lowe (1957) believed this to be the case and considered the specimens cited by Lloyd and Overholts from North America to be perennial speci- mens of P. licnoides. He consequently treated P. torulosus as an ex- cluded species in his monograph on the genus Fomes in North America. However, Lowe’s statement that P. licnoides is an annual form of P. torulosus is not in agreement with our conclusions. Field work in coniferous forests of southern Arizona over the past three years has disclosed the presence of Phellinus torulosus in that area. The following description of P. torulosus was prepared from data based on the 18 Arizona specimens cited. Capitalized color names are based on Ridgway (1912). The specimens from Arizona have been divided and are deposited in herbaria of the following institutions: The University of Arizona, Tucson (ARIZ); The Center for Forest Mycol- GILBERTSON AND BURDSALL : PHELLINUS TORULOSUS 1260 ogy Research, Forest Products Laboratory, U. S. Forest Service, Madi- son, Wisc. (BFDL); and The National Fungus Collections, Beltsville, Md. (BPI). PHELLINUS TORULOSUS (Pers.) Bourd. et Galz., Bull. Soc. Mycol. France 41 : 191. 1925. Polyporus torulosus Pers., Mycol. Eur. 2 : 29. 1825. Fomes torulosus (Pers.) Lloyd, Mycol. Notes, Polyp. Issue, No. 3, p. 48. 1910. Basidiocarps (FIGS. 1, 2) perennial, pileate, sessile, triangular in vertical sections with the upper surface horizontal and the pore surface at approximately a 45 degree angle, applanate to thick, up to 46 cm wide, 28 cm deep, and 11 cm thick; margin obtuse, rounded, up to 2 cm thick, upper surface buff to pale brown (Cinnamon-Buff to Clay Color), glabrous to finely tomentose or slightly strigose-matted, on older por- tions becoming blackened, sulcate; pore surface yellowish brown (Buck- thorn Brown), smooth, the pores 5-7 per mm, rounded, with thick, entire dissepiments; context yellowish brown, black in KOH solution, faintly zonate, hard and woody, up to 11 cm thick, with one or more thin, black layers that appear as fine black lines on cut or broken vertical surfaces; tube layers distinctly stratified, woody, slightly paler than context tissue. Contextual hyphae 2.5-5 µ in diam, thin-walled and hyaline to moderately thick-walled and bright yellowish brown, infrequently branched, with rare septa, clamp connections absent; tramal hyphae similar; setae (FIGS. 3, 4, 5) infrequent, ventricose to subulate, up to 49 µ long and 6-11 µ in diam, projecting 10-20µ ; basidia (FIG. 3) 4-sterigmate, clavate, 5-6 µ in diam; basidiospores (FIGS. 3, 4, 5) hyaline, smooth, negative in Melzer’s reagent, ovoid to ellipsoid, 4-6 × 3-4 µ. Specimens examined: ARIZONA-RLG 7887, 9385, 9386, 9387, 9388, ABB 1505, 1506, 1507, 1508, at base of southwestern white pine (Pinus strobiformis Engelm.), Summerhaven, Santa Catalina Mts., Coronado Nat. Forest, Pima County; RLG 9920, ABB 1512, at base of south- western white pine, Ski Area, Mt. Lemmon, Santa Catalina Mts.; HHB 1504, on Douglas fir [Pseudotsuga menziesii (Mirb.) Franco], Webb Peak area, Pinaleno Mts., Coronado Nat. Forest, Graham County; RLG 9394, 9397, 9396, ABB 1511, at base of southwestern white pine, RLG 7882, on roots of dead Douglas fir, and RLG 9390, at base of charred ponderosa pine (Pinus ponderosa Laws.) snag, Riggs Flat Lake, Pinaleno Mts. FRANCE-Dr.Pierrhugues, on Lauris nobilis, Toulon, CGL No. 5473 (BPI); H. Bourdot No. 3151, “sur aubépine,” St. 1261 MYCOLOGIA, VOL. 64, 1972 FIGS. 1-2. Basidiocarps of Phellinus torulosus. 1. RLG 9396 at base of 1 southwestern white pine, Santa Catalina Mts., Arizona, × /3. 2. Persoon Herb. 1 specimen No. 404, × /2. Priest, Allier, CGL No. 21537 (BPI); R. Maire No. 11495, on Picea excelsa, St. Martin-Vésubie (Alpes-Maritimes), CGL No. 21540 (BPI). CZECHOSLOVAKIA-Dr.Milosv Deyl, “ad truncos quer- cinos,” Parkán,V det. Dr. A. Pilát (ex-Herb. Prague, BPI). PORTU- GAL-Rev.C. Torrend, substratum not given, Lisbon, CGL No. 42834 (BPI). GILBERTSON AN D BURDSALL : PHELLINUS TORULOSUS 1262 FIGS. 3-6. Microscopic characters of Phellinus torulosus and P. gilvus. 3-5.P. torulosus. 3. HHB 1504, basidia, basidiospores, and setae. 4. CGL 5473, basidiospores and setae. 5. CGL 42834, basidiospores and setae. 6. P. gilvus, CGL 42835, basidiospores and setae. In addition, six specimens labeled Polyporus torulosus or Boletus torulosus from the Persoon Herbarium at Leiden were examined. None has the place of collection except No. 207, which is from “Gallia.” Four, Nos. 46, 62, 124, and 207, are small specimens and two, Nos. 404 (FIG. 2) and 409 are large. Number 409 also has “Polyporus torulosus, Mycol. Europ.” on a label attached to the specimen. Persoon originally 1 described the fungus as broad and thick (“Spithamin fere latus, 1 /2 unc fere crassus”). Specimen No. 409 is large (12 cm thick and 15 cm wide). As it also has the label which states “Mycol. Europ.” it seems 1263 MYCOLOGIA, VOL. 64, 1972 reasonable to assume that this specimen is the basis for the original description. An annotation label indicates that C. G. Lloyd arrived at the same conclusion. The European specimens, including those from the Persoon herb- arium, agree well in all respects, both macroscopic and microscopic, with those found in Arizona. We therefore conclude that the Arizona speci- mens are correctly referred to Phellinus torulosus. Basidiocarps of Phellinus torulosus macroscopically may resemble those of Phellinus nigrolimitatus (Rom.) Bourd. et Galz., a common fungus at higher elevations on conifer logs in the central and northern Rocky Mts., but apparently very rare in southern Arizona. Both P. torulosus and P. nigrolimitatus often have a spongy upper layer of context and thin black layers in the context that appear as fine black lines on cut or broken surfaces. Phellinus nigrolimitatus differs micro- scopically in having elongated, carrot-shaped spores and more abundant and slightly larger setae. Other species of Phellinus that have micro- scopic characters similar to those of P. torzdosus are Phellinus taxodii (Murr.) comb. nov. (basionym- Pyropolyporus taxodii Murr., Bull. Torrey Bot.