Retiboletus, Manfr. Binder & Bresinsky

Li, Jin, Wang, Zhen, Liu, En-De, Yang, Zhu L. & Li, Yan-Chun, 2022, Morphological and molecular data reveal Retiboletus cyanescens sp. nov. and the new subgenus Nigroretiboletorum (Boletaceae), Phytotaxa 572 (3), pp. 232-242 : 240-241

Key to the species of Retiboletus in China

1. Hymenophore bright yellow to brownish-yellow, stipe yellow to orange-yellow, mycelium on the base of stipe yellow to brownishyellow .................................................................................................................................................................................................2

1. Hymenophore whitish to grayish white, stipe black to blackish or grayish-black, mycelium on the base of stipe whitish to grayishwhite ...................................................................................................................................................................................................3

2. Basidiomata medium-sized to large, pileus up to 15 cm in diam.; distributed in subtropical to temperate forestes ........................... ........................................................................................................................................................................................ R. kauffmanii

2. Basidiomata small to medium-sized, pileus up to 10 cm in diam.; distributed in tropical forestes..................................... R. sinensis

3. Pileus smoky-gray to gray or black to grayish black, always with an olivaceous tinge; context of pileus white to grayish white with olivaceous tinge, staining brownish to fuliginous when injured; context of stipe dark green to olivaceous when cut, staining brownish to fuliginous when injured..................................................................................................................................................4

3. Pileus without olivaceous tinge; context of pileus white to grayish white without olivaceous tinge, color unchanged when hurt; context of stipe white to grayish white in the upper part and grayish yellow to brownish yellow at base, color without discoloration or sometimes staining brown when injured........................................................................................................................................5

4. Pileus smoky-gray to gray with olivaceous tinge; hymenophore initially white and then lilac to purplish; basidiospores 9–11 × 4–5 μm...................................................................................................................................................................................... R. zhangfeii

4. Pileus black to grayish black with olivaceous tinge; hymenophore white to grayish white without lilac to purplish tinge; basidiospores relatively small 8–10.5 × 3.5–4 μm............................................................................................................................. R. nigrogriseus

5. Basidiomata distributed in tropical forests; pileipellis a palisadoderm composed of vertically arranged broad hyphae up to 15 μm wide ....................................................................................................................................................................................................6

5. Basidiomata distributed in subtropical forests, or subtropical to temperate forests; pileipellis a palisadoderm composed of vertically arranged broad hyphae up to 16 μm wide, or a trichoderm composed of interwoven hyphae up to 8 μm wide ...............................7

6. Pileus brown to blackish brown; basidiospores 9.5–11 × 4–4.5 μm; basidia 23–29 × 8–10 μm; pleurocystidia 40–60 × 9–11 μm .. .................................................................................................................................................................................. R. pseudogriseus

6. Pileus pale brown to grayish brown; basidiospores relatively large measuring 10–12.5 × 4.5–5 μm; basidia relatively large measuring 35–40 × 10–12 μm; pleurocystidia relatively large measuring 50–80 × 9–14.5 μm................................... R. brunneolus

7. Basidiomata distributed in subtropical forests; pileipellis a palisadoderm composed of vertically arranged broad hyphae up to 16 μm wide ..............................................................................................................................................................................................8

7. Basidiomata distributed in subtropical to temperate forests; pileipellis a trichoderm composed of interwoven hyphae up to 8 μm wide ....................................................................................................................................................................................................9

8. Pileus black to blackish; basidiospores small mostly 8–10.5 × 3–4.5 μm; context in stipe without grayish green discoloration when injured....................................................................................................................................................................................... R. ater

8. Pileus dark brown, brown, black, or brown-gray in the center and brownish or grayish towards margin; basidiospores large mostly 10–13 × 4–5 μm; context in stipe with grayish green discoloration when injured .............................................................................. ....................................................................................................................................................................................... R. cyanescens

9. Pileus grayish brown to grayish black; basidiospores 9–12 × 3.5–4 μm .............................................................................. R. fuscus

9. Pileus grayish brown to brown without black tinge; basidiospores relatively large mostly 10–13.5 × 4–5 μm........... R. sinogriseus