Boletales » Sclerodermataceae » Scleroderma

Scleroderma yunnanense

Scleroderma yunnanense Y. Wang,

MycoBank number 805073

Basidiomata subglobose to globose, 2.5–5.0(–7.0) cm in diameter, with scales, dirty whitish to yellowish, the base attached to the substrate via a tuft of mycelium and rhizomorphs, sometimes aggregated into a pseudostipe, ≤2 cm long, conspicuously covered with well-developed rhizomorphs composed of hyaline hyphae, usually 2.0–3.0(–5) µm in diam., with emanating right branching hyphae and numerous clamp-connections and with some hyphae with adherent crystalline structure. Peridium 2–7 mm thick, two-layered, the outer layer ≤500 µm thick, composed of thin and thick yellowish hyphae towards the peridial surface, 1.5–2.0(–5) µm in diam.; the inner layer ≤6500 µm thick, composed of hyaline interwoven hyphae, 5.0–7.5 µm diam., clampconnections rare. Koh on the surface of peridium light reddish and no reaction on peridial cross-section. Gleba when young firm, white to whitish, and with numerous white capillitia, becoming grayish to purplish then purplish brown and finally powdery, composed of hyaline hyphae, 1.5–2.0 µm in diam., with a few dark, thick hyphae ≤3 µm in diam. Basidiospores globose to subglobose, (7.0–) 8.4 × 8.0(–9.5) µm including ornamentation, covered with dense narrow pyramidal warts, 1–1.2 µm long and 0.4–0.6(–8) µm thick at the base. Odor mushroomy; taste sweet.

Ecology & Distribution:  Sub-hypogeous, solitary or in small groups under Pinus kesiya var. langbianensis and Betula alnoides and forming ectomycorrhizae with one or both of these hosts, alt. 880–1300 m, fruiting from June to October in Yunnan, China. Known only from sub-tropical and tropical regions of Yunnan, China. Additional specimens examined: CHINA, Yunnan Province, Pure — 22º20’N 110º59’E, under Pinus kesiya var. langbianensis, 15 Sept. 2011: K.P. Ji S1102 (KUNHKAS 79664; GenBank JQ639044, JQ639045); under Betula alnoides, 15 Sept. 2011: K.P. Ji S1103 (KUN-HKAS 79665; GenBank JQ639046); Puwen — 22º30’N 101º03’E, under Pinus kesiya var. langbianensis, 24.Sep.2011: Ji S1104 (KUN-HKAS 79666), Ji S1105 (KUN-HKAS 79667), Ji S1106 (KUN-HKAS 79668); Yiliang — 24º92’N 103º14’E, 12.Sep.2007: T. Ma, YL007 (IFRD 414-012, as “Scleroderma citrinum,” GenBank FJ687275); Wuiding — 25º55’N 102º36’E, 12.Aug.1998: X.H. Wang 742, KUN-HKAS 35824, as “Scleroderma citrinum”).

Notes: ITS-rDNA sequence analysis groups all S. yunnanense collections with high (99%) bootstrap value and separate from the S. citrinum collections, which also group with high (97%) bootstrap value. The discovery of an edible Scleroderma species in a genus long considered toxic (or at least highly suspect) underlines the difficulties in generalizing the edibility or toxicity of mushrooms. In the Yunnan area where S. yunnanense is widely consumed, there is presumably sufficient general knowledge to prevent the eating of inedible or toxic lookalikes. However, the likely publicity surrounding the edibility of S. yunnanense might now persuade some people to try eating potential lookalikes outside of the natural range of this species. Fortunately, the misidentification of S. yunnanense as S. citrinum Pers. (a toxic species) should be lessened based on the accurate morphological information that we present. Morphologically Scleroderma yunnanense is similar to S. cepa Pers. in having spiny spores and thick peridium. However, it differs in having clampconnections. The ITS-rDNA sequence analysis shows that S. yunnanense is closely related to S. sinnamariense Mont. However, S. sinnamariense has a thinner (<1 mm) peridium, a bright sulfur yellow inner peridial surface, and partially reticulate spores, all of which differ in S. yunnanense.



Fig. 1 ITS-based neighbor-joining phylogenetic tree of Scleroderma species. Sequences are labeled

with their GenBank accession numbers. Bootstrap support values (1000 replications)

>50% are shown on the nodes.