Chiua Y.C. Li & Zhu L. Yang, in Wu et al., Fungal Diversity 81: 76 (2016)
Etymology: ‘‘Chiua’’ is in honor of the late Prof. Wei- Fan Chiu, who first studied and monographed boletes in Yunnan around the middle of the 20th century.
Diagnosis: This genus differs from all other genera of Boletaceae in its scabrous stipe surface and chrome yellow stipe base, yellow to chrome yellow pileal and stipe context which is without color change when hurt, white to pinkish or pink hymenophore, trichodermium pileipellis and smooth basidiospores.
Basidioma stipitate-pileate with tubular hymenophore. Pileus hemispherical, to subhemispherical or convex; surface subtomentosus, dry, slightly extended at the margin when young; context yellow to bright yellow, unchanging in color when injured. Hymenophore depressed around apex of stipe; hymenophoral surface white when young, and becomes pinkish or pink to purplish when mature; pores angular or roundish; tubes concolorous with hymenophoral surface, unchanging in color when injured. Stipe central, yellow to lemon yellow at upper part, bright yellow to chrome yellow at the base; basal mycelium chrome yellow. Basidiospores smooth, subfusiform. Pleuro- and cheilocystidia subfusiform to ventricose or clavate. Pileipellis subcutis or trichodermium composed of filamentous interwoven hyphae, or hypoepithelium composed of filamentous hyphae and concatenated subglobose cells. Clamp connections absent.
Index Fungorum number: IF818401
Notes: Chiua generally shares the same colored hymenophore and basidiospore deposit with Austroboletus, Fistulinella, Harrya Halling et al., Royoungia, Tylopilus s.s., Zangia and some species in Porphyrellus, but Chiua is characterized by the yellow to chrome yellow pileal context, the pink scabrous squamules on the stipe which do not darken in age, the chrome yellow colored base of the stipe, and the smooth basidiospores. Austroboletus is characterized by lightly to heavily ornamented basidiospores with pits, warts or reticulations which are significantly different from the above genera (Wolfe 1979a, b; Singer 1986; Fulgenzi et al. 2010). Fistulinella has a viscid to glutinous basidioma with a white to dirty white stipe base and a trichoderm, ixotrichoderm or ixocutis (Redeuilh and Soop 2006; Fulgenzi et al. 2010). Porphyrellus differs from Chiua in the morphology of the stipe, the color of the context and color changes when bruised. The dotted squanmules stipe in Chiua can be observed in some species of Leccinum. However, Leccinum possesses grayish, brownish or yellowish but never pink to pinkish hymenophores, and the ornamentations on the surface of the stipe usually become darker with age (den Bakker and Noordeloos 2005). Notably, Chiua is macro-morphologically similar to Harrya, Royoungia and Zangia. But they are different in morphology (such as the pileal contex color, the discoloration when cut, and the pileipellis structure) and molecular phylogenetic evidence (Li et al. 2011; Halling et al. 2012). Four species have been found in China.
Type species: Chiua virens (W.F. Chiu) Yan C. Li & Zhu L. Yang 2016, in Wu et al., Fungal Diversity 81: 76 (2016)
Chiua angusticystidiata Y.C. Li & Zhu L. Yang 2016
Chiua olivaceoreticulata Y.C. Li & Zhu L. Yang 2016
Chiua virens (W.F. Chiu) Yan C. Li & Zhu L. Yang 2016
Chiua viridula Y.C. Li & Zhu L. Yang 2016
Wu, Gang & Li, Yan-Chun & Zhu, Xue-Tai & Zhao, Kuan & Han, Li-Hong & Cui, Yang-Yang & Fang, Li & Xu, Jianping. (2016). One hundred noteworthy boletes from China. Fungal Diversity. 81. 10.1007/s13225-016-0375-8.