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Page number:789 
Remarks (public):Laurilia sulcata, which is carefully described by Gross (loc. cit.) under the name of Echinodontium sulcatum, is one of the most characteristic stereoid fungi and cannot be mistaken for any other resupinate. 
Description type:Non-original description 
Description:Laurilia sulcata (Burt) Pouzar, Ceská mycol. 13 p. 14, 1959.-Stereum sulcatum Burt in Peck, N.Y. St. Mus. Ann. Rep. 54 p. 154, 1901.- Echinodontium sulcatum (Burt) Gross, Mycopath. mycol. appl. 29:1 p. 8, 1964.
Fruitbody resupinate or partly pileate, perennial, leathery or when old, partly ligneous, first orbiculate, with time confluent, reaching several dm2 and becoming really conspicuous; upperside often, esp. in young specimens, covered with a brown, tinder-like tomentum, 1-5 mm thick, in old specimens mostly dark brown to blackish, often with concentric furrows and ridges, resulting from the peripheral growth of the fungus; fruitbody in section stratified with a superior tinder-layer, then a thin hard, resinous layer visible as a dark line, then a subicular trama which is lightcoloured like the subicular layer, in old fruitbodies the tinder may be worn off or filled with resinous substances into a single hard stratum; hymenium in young specimens smooth, then tuberculate or concentrically sulcate, light yellowish with a tint of salmon, when old pale ochraceous, the herbarium; a drop of KOH on the hymenium gives an orange colour, the fresh trama turns reddish when bruised; margin in young fruitbodies white, finely fibrillose, then more glabrous, smooth or somewhat thickened, in old specimens margin consisting of parallel ridges, the result of a. receding hymenium, leaving a new sterile zone every year, the same as can be seen in some polypores (Fomitopsis rosea, Phellinus nigrolimitatus).
Hyphal system trimitic, consisting of straight, thickwalled skeletal hyphae, 2,5-4 µm wide, with sparse septa and clamps, richly branched thickwalled binding hyphae, 2-3 µm wide, and thinwalled, richly branched fibulate hyphae, 2-3 µm wide, with some adventitious septa; the upper tinder-layer consists mainly of brown skeletal hyphae, the subiculum of hyaline or pale yellowish, thickwalled, horizontal skeletals with numerous binding hyphae between them, as well as few generative hyphae, at least in young specimens; subhymenium of vertical skeletals, irregular binding hyphae, generative hyphae, cystidia and old, shrunken basidia.
Cystidia numerous, thickwalled, apically conical, encrusted, basal part tapering to the bearing hyphae, somewhat pigmented, yellowish or pale ochraceous in the proximal part, total length 40-65 µm,
encrusted part 20-30 µm, greatest width 8-10 µm. The inner structure of the cystidia is somewhat unclear. They seem to consist of two parts, a proximal pigmented part, evidently formed by thickening of the wall, and a distal part which in old cystidia is as a rule hyaline. We have not been able to decide whether the two parts are separated by an adventitious septum or not. It should be possible to solve this problem with the aid of transmission electron microscopy.
Basidia clavate, 25-35 x 4-5 µm, with 4 sterigmata and basal clamp.
Spores globose or somewhat subglobose, echinulate, with somewhat thickened walls, amyloid, 5,5-6,5 x 5 µm.
Habitat. On fallen logs of Picea abies preferably in virgin forests at higher altitudes. The habitat in Scandinavia is usually the normal Hylocomium-Vaccinium-Picea forest, but it is also found in poorer, drier communities, e.g. Cladina-Empetrum-Vaccinium-Picea or in rather wet ones with patches of Sphagnum and Equisetum. It grows together with some very characteristic fungi like Phellinus abietis (=chrysoloma), ferrugineofuscus and nigrolimitatus, Fomitopsis rosea, Phlebia centrifuga, Incrustoporia stellae and tschulymica, Amylocystis lapponicus a.o. but in Scandinavia, at least, it seems more restricted to higher altitudes than any of these fungi, 700-900 m in the S, 300-600 m in the N. It certainly plays an important role in the ecology of these forests, as it, together with the enumerated species, is able to decompose wood under the unfavourable climatical conditions prevailing in this area. It causes an extended white rot in fallen trunks. It is not clear if the decay starts already in the living trees, though this seems probable.
Distribution. Laurilia sulcata is in N. Europe restricted to areas with a pronounced continental climate. Thus, it has two separate areas of distribution on the eastern side of the Scandian mountains. The southern area goes from the NW part of Dalarna in Sweden into the adjacent counties Hedmark and Oppland in Norway. It is not found in the lower part of the mountain range between Jämtland in Sweden and Trondelag in Norway where there is a more oceanic climate. It reappears in a northern area from inner Swedish Lapland to inner North Finland. The bicentric distribution was detected by Eriksson in the 1940:s and has since been confirmed through intense field studies by several mycologists. The distribution was mapped by Ryvarden (Norw. Journ. Bot. 18:2 p. 101, 1971). Since then several new finds have been made but they do not alter the picture. Within the areas it is easily found, being relatively frequent and very conspicuous. The bicentricity of the fungus has nothing to do with the discussions concerning the bicentricity of some alpine higher plants in Scandinavia which involve theories about refuges during glacial periods. It only reflects the existing climatic conditions. Thanks to the effectiveness of the dispersal of fungi, they are excellent objects for studies of distribution in relation to ecological conditions.
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