Lactarius aff. gerardii
Lactarius aff. gerardii Peck, Bull. Buffalo Soc
Pileus 20-90 mm diam., plano-convex with papilla to slightly depressed or subumbilicate with irregular papilla, sometimes applanate; surface dry, glabrous to slightly velvety, sometimes smooth but in centre mostly radially rugulose and towards the margin veined or grooved, dark yellowish brown (5D4, 5EF6, 5F7) and dark brown (6F7/8) near the margin; margin irregularly crenulate or wavy, in older specimens sometimes faintly, translucently striate. Lamellae decurrent to deeply decurrent with tooth, subdistant to distant, 1.5-11 mm broad, yellowish white (2/3A2) to pale yellow (4A3), 2-3 lamellulae between 2 lamellae; edge smooth, often brown (5E3/4) on the entire length. Stipe 30-82 × 6-17 mm, central to eccentric, equal or tapering downwards, cylindrical; surface dry, smooth or with shallow longitudinal wrinkles, concolourous with pileus, dark brown (5/6F7/8) or yellowish brown (5E7), the base often paler (5D5) or even whitish. Context 1.5-6 mm thick in pileus, hollow in stipe, white, unchanging; yellowish white with 10% KOH, pale orange with FeSO4; smell not remarkable; taste mild, slightly sweet. Latex abundant, white, unchanging; pale yellow with 10% KOH. Spore print colour unknown. Basidiospores 6.6–7.9–9.3 × (5.4)5.8–7.1–8.4 μm (Q = 1–1.12–1.3; n = 20), globose to broadly ellipsoid; ornamentation up to 0.5 (1.8) μm high, forming a ± complete reticulum, ridges broad and stout, rounded, never acute; plage centrally diffusely amyloid. Basidia 42-72 × 9.5-11.5 μm, subcylindrical to clavate, hyaline or with guttate content, 4-spored; sterigmata 5-14 × 1.5-3 μm. Pleuromacrocystidia absent. Pleuropseudocystidia 8-10 μm diam., abundant, emergent, cylindrical and often somewhat tortuous, thin-walled, with lactiferous contents. Hymenophoral trama mostly cellular or with frequently septate hyphae; lactifers moderately abundant. Lamellar edge sterile; cheiloleptocystidia 22-50 × 3-7 μm, subcylindrical to subfusiform, thin-walled, hyaline or with brown intracellular pigmentation. Pileipellis a palisade, 33-100 μm thick, with brown intracellular pigmentation; suprapellis composed of terminal elements (18-37 × 5 μm), subcylindrical, thin-walled; subpellis composed of few to several layers of inflated cells, 9-25 μm diam. Stipitipellis a palisade, 25-70 μm thick, containing intracellular, brown pigmentation, sometimes resembling a trichoderm because of a very degenerated subpellis; terminal cells 15-25 × 5-6 μm, subcylindric to subfusiform, thin-walled, erect or oblique; subpellis composed of few layers of inflated cells, sometimes barely forming a layer.
Habitat and distribution: Rather common in June during the beginning of the rainy season, in the mid-elevation rainforests of northern Thailand and southern China. Associated with Lithocarpus or Castanopsis.
Material Examined: THAILAND: Chiang Mai Province, Mae Taeng Distr., Ban Pa Deng village, at MRC, in montane rain forest, 01/06/2004, Huyen T. Le 101 (CMU, GENT, SFSU) – Chiang Mai Province, Doi Suthep-Pui National Park, Sangasahasri Lane to Huai Kok Ma village, N18°48.62' E98°54.60', alt. 1145 m, primary montane rain forest with Castanopsis spp. and Lithocarpus polystachyus, 30/06/2003, DED 7599 (CMU, SFSU, GENT) – ibid., 24/06/2004, Huyen T. Le 134 (CMU, SFSU, GENT) – ibid., 24/06/2004, Huyen T. Le 135 (CMU, SFSU, GENT) – ibid., 24/06/2005, Huyen T. Le 295 (CMU, SFSU, GENT) – ibid., 24/06/2005, Huyen T. Le 302 (CMU, SFSU, GENT) – ibid., 02/07/2005, Huyen T. Le 343 (CMU, SFSU, GENT) – ibid., Huyen T. Le 411 (CMU, SFSU, GENT) – Chiang Mai Province, Mae Taeng dist., Ban Pha Deng village, at the MRC in plot 11, area dominated by Lithocarpus spp., 13/09/2004, Huyen T. Le 246 (CMU, GENT, SFSU) – Chiang Rai Province, Khun Chae National Park, alt. 963 m, N19°04' E99°23', montane rain forest dominated by Castanopsis armata, Castanopsis spp. and Pinus spp., 10/06/2005, Huyen T. Le 270 (CMU, SFSU, GENT) – Chiang Mai Province, Doi Inthanon National Park, junction of highway 1009 and road to Mae mixed forest with Dipterocarpus spp. and Pinus kesiya, under P. kesiya, 04/06/2006, Huyen T. Le 394 (CMU, SFSU, GENT) – Chiang Mai Province, Doi Inthanon National Park, Highway 1009 at 25 km marker, N18°32.54' E098°33.51', 1076 m alt., montane rain forest dominated by Castanopsis armata and Pinus sp., 05/06/2006, Huyen T. Le 404 (CMU, SFSU, GENT).
Notes: The above description is based on Huyen T. Le 270, and is presented here as an example of several similar collections that have been made in the same or other localities in Northern Thailand. All of them are characterized by a dark brown, rugose cap, whitish and distant lamellae often with a dark brown edge, contrasting with the dark brown stipe, and exhibiting no discoloration in context nor latex. The phylogenetic analyses of the Thai specimens show that they indeed form one clade together with the American L. gerardii (Verbeken 05-235) (Fig. 1). What is more, the analyses reveal within the gerardii-group, two highly supported clades that could not be correlated with any distinct morphological findings. A study by Verbeken, Wang and Stubbe (in preparation) compares North American collections of L. gerardii with East Asian look-a-likes (from China, Korea and Japan) and with the closely resembling Malayan species L. bicolor Massee. The basidiospores of these East Asian collections appear to be globose to subglobose instead of ellipsoid like those of their American counterparts. Due to this difference, and acknowledging the geographical disjunction, a new subspecies will be described for these East Asian collections. Lactarius bicolor differs from L. gerardii by the bigger and thin-fleshy basidiocarps, globose to subglobose basidiospores and stouter terminal elements in the pileipellis and lamellar marginal cells. The phylogenetic analyses presented here also indicate the gerardiicomplex as a separate clade from the other members of L. subg. Plinthogali. Unpublished data (by Stubbe et al.) even confirm its complete removal from the subgenus, despite the very fitting morphological characters. In light of these findings and the new collections made in Thailand, a more broad-scaled and molecular approach will be required to untangle the exact nature of the species complex surrounding L. gerardii.
Fig. 1 MP phylogeny of Lactarius subgenus Plinthogali in Northern Thailand based on ITS sequences. The 50% majority rule consensus tree resulting from the Maximum Parsimony analysis with the bootstrap values higher than 50% added on the internal nodes.
Fig. 2 Lactarius aff. gerardii. a. basidiomes, b. basidiospores, c. basidia, d. cheiloleptocystidia, e. pleuropseudocystidia, f. pileipellis, h. stipitipellis. Scale bars = 10 mm (basidiomes) and 10 μm.
Reference
Recent News
Nutritional analysis of cultivated Pleurotus giganteus in agricultural waste as possible alternative substratesutilization notes of the edibility, economic and medicinal value and if the mushroom is cultivated
The genus Lentinus in Thailand: taxonomy, cultivation tests, nutritional analysis and screening for the biological activity of wild strains
Recent Genus
TricholomopsisErythrophylloporus
Boletinellus
Recent Species
Lactarius lavandulusRussula zonaria
Russula sribuabanensis