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Page number:311 
Remarks (internal):Bothia can be characterized most easily by the more or less uniformly brown to dark brown colors, soft texture, conspicuously boletinoid and decurrent, pale brown hymenophore, reticulate/pseudoreticulate stipe, and pale brown spore deposit. Basidiome appearance in consistent association with oak seems diagnostic also. An excellent color illustration appears in Roody (2003).
Phylogenetic analyses unequivocally place Bothia castanella in the Boletaceae (FIG. 7 ) with strong support (bootstrap = 96%, posterior probability = 1.0) and relationships to Paxillaceae, Boletinellaceae and Suillaceae can be rejected. A sister group of B. castanella was not resolved in this study; however the monotypic genus formed a clade with the Xerocomus chrysenteron group that receives no statistical support. We ran constrained analyses forcing Bothia and the X. chrysenteron group (X. chrysenteron, X. cisalpinus, X. dryophilus, X. porosporus, X. pruinatus, X. ripariellus, X. truncatus and allies in Fig. 7) into a single clade and evaluated monophyly comparing constrained and unconstrained trees with the KH-test (Kishino and Hasegawa 1989 ). Although a relationship was not rejected statistically (P = 0.204), only a few morphological characters (e.g. epicuticular hyphae with spiral incrustations) would support a connection between Bothia and the X. chrysenteron group.
The morphological features displayed by B. castanella have contributed to its placement in several genera. Overwhelming reliance on one feature over another (e.g. hyphal arrangement in the hymenophoral trama) apparently seems to have played a part as well. First, the radially elongated tubes is a feature seen in some Suillus species (Boletinus is considered a synonym), Gyrodon and Boletinellus. However Bothia castanella lacks the clustered hymenial and caulocystidia with amorphous pigment seen in Suillus and ecologically is not associated with Pinaceae. Unlike Gyrodon and Boletinellus, B. castanella does not produce olive brown spores in deposit, is not cyanescent, lacks clamp connections and the hymenophore is a pale brown (not yellow). The arrangement of the tube trama lacks a central zone and thus would be of the Phylloporus-type in the sense of Singer (1986) , an overriding factor directing placement in Xerocomus for some (Singer 1986, Snell and Dick 1958). Morphologically Xerocomus produces an olive brown spore deposit and lacks other cohesive features (Oolbekink 1991). Thus the unique combination of morphological features and apparent mycorrhizal association exhibited by Bothia further support generic recognition.
The dense dark brown encrustations of the pileus surface hyphae dissolve readily in 3% KOH and 10% NH4OH, producing only brownish or pale vinaceous discolorations in the mounting medium. These pigments slowly dissolve leaving hyaline or yellowish brown intracellular pigments in the surface hyphae. This reaction is useful in helping to identify dried herbarium materials of this species.
 
Description type:Non-original description 
Description:Bothia castanella (Peck) Halling, T. J. Baroni, & Binder, comb. nov. FIGS. 1-7
Boletinus castanellus Peck, Bull Torrey Bot Club 27:613. 1900.
Boletinellus castanellus (Peck) Murrill, Mycologia 1:8. 1909.
Gyrodon castanellus (Peck) Singer, Rev Mycol (Paris) 3:172. 1938.
Xerocomus castanellus (Peck) Snell & Dick, Mycologia 50:58. 1958.
Suillus castanellus (Peck) Smith & Thiers, Contr monogr N Amer sp Suillus. 26. 1964.
Chalciporus castanellus (Peck) L.D. Gómez, Rev Biol Trop 44(4):78. 1996 (1997) nom. inval. (Art. 33.3).
Holotype: - USA. New Jersey. September, E.B. Sterling (NYS), apparently missing. Neotypus: Halling 6636 (NY), here designated.
Boletinus squarrosoides Snell & Dick in Snell, Mycologia 28:468. 1936.
Phylloporus squarrosoides (Snell & Dick) Singer, Rev Mycol (Paris) 3:170. 1938.
Xerocomus squarrosoides (Snell & Dick) Singer, Farlowia 2:295. 1945.
Holotype: - USA. Pennsylvania. Reading, Mt Neversink, E.A. Dick 532 (BPI! #783691).
The following description of macroscopic features includes observations compiled by Ernst Both, for whom the new genus is named.
Pileus 30-90(-100) mm broad, convex to planoconvex, becoming depressed on the disk in age, dry, coarsely tomentose to granular tomentose or with tomentum aggregated into fibrils, at times ± appressed fibrillose, sometimes with an irregular to wavy margin, dark reddish brown becoming dark brown to very dark brown (between Russet and Cinnamon Brown) or very dark chocolate brown (Carob Brown to Chestnut Brown) when young, fading at times to Rood's Brown or Mikado Brown to Sayal Brown, sometimes with margin nearly blackish brown. Flesh soft textured, white to dingy whitish, unchanging or slowly becoming a dingy pale rust color, with odor absent and taste mild or ± acidulous. Hymenophore tubulose, decurrent when young, shallowly depressed around stipe with age but still decurrent, with tubes 4-5(-10) mm long; pores boletinoid, coarse and angular to hexagonal, usually compound, 3-4 mm broad, sublamellate at the stipe, dull pallid brown to cinnamon brown with pinkish cinnamon tones (near Cinnamon Buff to Clay Color), usually staining brown to dark brown or dark rusty brown (Cinnamon Brown, Cinnamon, Sayal Brown). Stipe 20-60 mm long, (10-)13-18 mm broad above, 8-16 mm broad below, equal or tapering downward, occasionally broader at apex and base, central or eccentric, dry, usually paler than pileus and approaching pale vinaceous brown or spotted sooty brown, sometimes stained reddish at the base, otherwise bruising blackish brown when fresh, coarsely and shallowly reticulate in upper half or confined to apex, pseudoreticulate to striate ridged and minutely tomentose to densely and finely furfuraceous below, with reticulum darker brown than background color, with white basal mycelium, with interior solid, brownish to pale cinnamon toward the base.
Spores yellow brown (5C6) in fresh deposit, (7.7-) 8.4-10.5(-11.3) x (3.5-)4.2-4.9(-5.6) µm, n = 20, x = 8.8 x 4.5 µm, Q = 1.98, ellipsoid to long ovoid, inamyloid, hyaline to pale brownish yellow, smooth, thin-walled. Basidia 25-35 x 7-9 µm, clavate, 4-sterigmate, hyaline or rarely with brownish yellow contents, with coagulated dextrinoid content in Melzer's. Hymenial cystidia present and conspicuous as pleuro- and cheilocystidia, the latter especially abundant, fusoid to fusoid ventricose or sometimes ventricose rostrate, hyaline or rarely with pale brownish yellow content, inamyloid, smooth, thin-walled, 45-70 x 7-12 µm. Hymenophoral trama bilateral, with lateral elements 5-9 µm wide, hyaline, or rarely with oleiferous elements, subgelatinized with age; a differentiated central zone not apparent. Pileus trama interwoven, hyaline, inamyloid, with elements 5-14 µm wide, smooth, thin-walled. Pileipellis a trichodermium, with erect to suberect, cylindric hyphae, smooth, hyaline or sometimes with yellowish brown contents in KOH, hyaline or with orange brown contents and occasional orange brown encrusting pigment in Melzer's, inamyloid, with dark brown, dense, plaque-like and spiral encrustations in dH2O, dissolving in dilute alkali, thin-walled, 4-7 µm wide. Stipitipellis hymeniform, with clavate cells and occasional basidia, rarely with scattered caulocystidia. Stipe trama parallel, cylindrical, vertically oriented, hyaline, inamyloid, with scattered oleiferous elements. Clamp connections absent.
Habit, habitat, and distribution: solitary to gregarious, rarely cespitose, under oaks, with birch, beech, hickory, eastern white pine, and hemlock sometimes present. Currently known in the eastern United States from the Carolinas northward to New York and New England and westward to Minnesota, appearing Jul-Sep. William Roody (pers com) has recorded eight specimens from West Virginia on deposit in DEWV.
 
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