Three new species of Lactarius subgenus Lactiflui (Russulaceae, Russulales) in southwestern China

摘要

Three new species of Lactarius subgen. Lactiflui are described from tropical and its adjacent regions in southwestern China. Lactarius longivelutinus is characterized by the basidiocarps with an eccentric to almost lateral stipe, very long terminal cells in the pileipellis (300-400 mu m long) and a lamprotrichoderm as a stipitipellis structure with terminal cells 6.0-7.0 mu m wide and walls 2.0-4.0 mu m thick. Lactarius pseudoluteopus is similar to the tropical African L. luteopus because of its bright yellow stipe and lamellae margin and the brittle basidiocarps, but can be distinguished from the latter by the long marginal cells and absence of macrocystidia. It differs from the American L. hygrophoroides by its long marginal cells and much longer terminal cells in the pileipellis. Lactarius tenuicystidiatus is characterized by the rather robust basidiocarps with whitish stipe, the presence of thin-walled true macrocystidia, and the lowly ornamented basidiospores (up to 0.2 mu m high). This is the first time that a member of Lactarius sect. Pseudogymnocarpi is recorded outside tropical Africa.