Search on : Taxa descriptions


 Add this item to the list  807127 Original description
Page number:830 
Remarks (internal):Macroscopically B. orientialbus appears close to B. cremeus Corner and B. purus Corner, both of which are also pure white boletes from Fagaceae forest on Mount Kinabalu (Borneo) allied with sect. Boletus (fide Corner 1972 p 164) but appear to differ from B. orientialbus in microanatomy and from B. albobrunnescens in the lack of bruising.  
Description type:Original description 
Description:Boletus albobrunnescens Desjardin, Dentinger & Arora, sp. nov. Figs. 1, 2
MycoBank MB807127
Diagnosis: Differs from others in sect. Boletus by the pure white basidiomata, staining dark brown.
Type: Thailand. Chiang Mai Prov., Doi Inthanon National Park, 25 km marker on Hwy 1009, 18°32.56′N, 98°33.51′E, 1075 m, 27 Jun 2005, D.E. Desjardin 7854 (Holotype: MFLU, Isotype: SFSU).
Pileus 5.5-11 cm broad, hemispheric becoming broadly plano-convex, uneven to undulate with age, dry to subviscid, glabrous to finely matted, pure white overall, staining brown to dark reddish brown (10F8). Flesh white, unchanging, with mild odor and flavor or sometimes with slightly bitter aftertaste. Tubes adnexed, white with pores covered with white hyphae at first, eventually olive yellow (3C7,6,5) to olive brown (4E8,7,6), unchanging when bruised. Stipe 6-11 cm long, 1.5-2 cm broad, 2.5-3.5(-5) cm broad at base, clavate or ±e qual-cylindrical with a swollen base, dry, white, strongly reticulate at apex to finely reticulate over half the length, staining brown or chocolate brown.
Basidiospores 10.5-11.9 x 4.2-4.9 µm (n = 20; x = 11.31 x 4.62 μm; Q = 2.45), subfusoid to fusoid, with smooth walls, hyaline to pale melleous in KOH, inamyloid or a minority weakly dextrinoid in mass. Basidia 20-26 x 10-12 mm, short-clavate, hyaline, four-sterigmate. Hymenial cystidia present, broadly fusoid to broadly ventricose or nearly ventricose-rostrate, hyaline, inamyloid, thin-walled, 30-40 µm long. Tube trama boletoid and divergent, with melleous central strand; the lateral strata elements hyaline, 3-12 µm wide, subgelatinous with age. Pileipellis hyphae interwoven and repent, with elements 5-10 µm broad, smooth, hyaline or sometimes with dull mustard brown content. Pileus trama interwoven, hyaline, rarely with oleiferous elements, inamyloid, with thin-walled hyphae 3-14 µm wide. Stipitipellis hyphae forming a hymeniform layer with clavate to short ventricose caulocystidia, 25-45 µm long, hyaline, thin-walled, arising from vertically oriented contextual elements, 5-14 µm broad, hyaline and thin-walled, rarely with oleiferous contents. Clamp connections absent.
Habit, habitat and distribution: solitary to scattered in soil of mixed evergreen/deciduous forest under Pinus and Castanopsis. At present known only from Thailand.

Taxon name: