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 Add this item to the list   Daedalea xantha (Fr.) Roy & De, comb. nov.
   
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Page number:421 
Description type:Non-original description 
Description:Daedalea xantha (Fr.) Roy & De, comb. nov.
Basionym: Polyporus xanthus Fr., Obs. 1: 128, 1815 = Poria xantha Fr. Cke., Grevillea 14: 112, 1886
Basidiocarp annual, extensively effused, adnate, soft when fresh, chalky white when dry, subiculum less than 1 mm thick, surface cream to sulphur yellow when fresh, fading to white or cream and freely cracking into blocks on drying; pores circular, 5-6 per mm, pore tubes white, up to 3 mm thick.
Hyphal system trimitic. Generative hyphae hyaline, thin-walled, 2-4 µm in diam. (Fig.l), some thick-walled, thickening often irregular (Fig.2), 2.5-7.0 µm in diam. Skeletal hyphae (Fig.3) abundant, hyaline, unbranched, thick-walled to subsolid, 2.2-6.5 µm in diam. Binding hyphae (Fig.4) few, hyaline, shortly branched, 2.5-5.0 µm in diam. Both the skeletal and binding hyphae rarely showed thin-walled clamped cell at their basal septa. Basidia (Fig.5) clavate, 4-sterigmate, 10-15 x 4-5 µm Basidiospores (Fig.6) allantoid, hyaline, thin-walled, 4.0-5.0 x 1.0-1.5 µm. The spore sizes with data on the number of spores measured and the number of the specimens examined are given below
Number of the Number of spores Basidiospore
specimens measured sizes
VBMH 89901 20 4.5-5.0 x 1.2-1.5 µm
VBMH 89902 20 4.0-5.0 x 1.0-1.5 µm
VBMH 90903 20 4.0-4.5 x 1.0-1.3 µm
VBMH 91904 20 4.0-5.0 x 1.0-1.5 µm
VBMH 93905 20 4.0-5.0 x 1.0-1.4 µm
VBMH 93906 20 4.0-5.0 x 1.0-1.5 µm

SPECIMENS EXAMINED : VBMH 89901 and VBMH 89902, growing on dead wood of Pinus excelsa Wall. ex Don, Sojar, Suraj Division (Punjab); VBMH 90903, on a dead ranch of Pinus wallichiana Jacks., Pulga (H.P.); VBMH 91904, growing on log of ercus semeca ifolia Sm., Banjar Range (Punjab);
VBMH 93905, on log of ercus semecar i o is Sm., Toshnal (H.P.); VBMH
93906, on log of ercus semecarpi o ia Sm., Kulu (H.P.).

DISCUSSION
The aforesaid description indicates that Poria xantha has a trimitic hyphal system and thus contradicts the views held -by earlier workers (Bakshi 1971, Rattan 1977, Melo 1984, Rajchenberg 1984, Gilbertson and Ryvarden 1986, Rayvarden and Gilbertson 1990) who considered it as dimitic with generative hyphae and skeletal hyphae. Bakshi (1971), Rattan (1977), Gilbertson and Ryvarden (1986) and Ryvarden and Gilbertson (1990) recorded the rare presence of branched skeletal hyphae. We also noted the occurrence of aseptate thick-walled hyphae with short branches in all the basidiocarps though they were few in number. Our critical observations revealed that they were true binding hyphae and not branched skeletals as reported by the earlier workers because they were short, branched with many short branches and showed thin-walled clamped cell at their basal septa. Therefore, P. xantha is not dimitic but trimitic in construction with scanty and rudimentary binding hyphae. It may be mentioned here that we have recorded some thick-walled clamped generative hyphae in P. xantha which often showed irregular wall thickening. This type of generatÀ­ve hyphae have also been recorded by Rajchenberg (1984) although these have not been observed by Gilbertson and Ryvarden (1986) and Ryvarden and Gilbertson (1990).
P. xantha has been described by several authors under different genera viz. Amyloporia, Antrodia and Poria. But P. xantha shows the closest resemblance with Daedalea quercina L.: Fr., the type species of the genus Daedalea. though Van der Westhuizen (1971), from comparative cultural and anatomical studies on D. quercina, concluded it to be a dimitic species, the prevailing opinion, see Cunningham (1948), Teston (1953), Kotlaba and Pouzar (1957), Domanski et al. (1973), and Ryvarden (1976), is that this species is trimitic with 'scanty and rudimentary binding hyphae (Reid 1976). In possessing a trimitic hyphal system with thin-walled as well as thick-walled generative hyphae including generative hyphae with characteristic irregular wall thickening (Van der Westhuizen 1971), skeletal hyphae and scanty and rudimentary binding hyphae (Reid 1976) D. quercina closely resembles P. xantha.
Besides, like P. xantha D. quercina causes a brown rot, produces no extracellular ˵i asse in cu ture and possesses a bipolar type of sexuality (Nobles 1965). The species code of D. quercina (Nobles 1965) also comes close to that of P. xantha. So many features in common suggest a close relationship between P. xantha and D. quercina. Therefore, it is concluded that P. xantha and Daedalea quercina are congeneric and the following new combination is proposed: Daedalea xantha (Fr.) Roy & De, comb. nov.
 
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