Scytalidium album L. Beyer & Klingstrom

1.Scytalidium albumL. Beyer & Klingström, Svensk bot. Tidskr. 59: 35 (1965) Description and illustration. Klingström and Beyer (1965). Notes. Scytalidium album was initially isolated from Norway spruce wood damaged by root rot, and it induces blue staining in timber (Klingström and Beyer 1965). Scytalidium album is phylogenetically closely related to S. assmuthi, S. aurantiacum, S. rodionovae, S. circinatum, S. terrigenum, and S. tongrenense (Figs 1, 2). Morphologically, S. album is distinguished from S. assmuthi, S. rodionovae, and S. tongrenense by its unknown sexual morph and simultaneous production of arthroconidia and chlamydospore-like cells (Klingström and Beyer 1965; Pavlov et al. 2018; Manawasinghe et al. 2024). Scytalidium album differs from S. terrigenum by its hyaline arthroconidia (Jeong et al. 2025) and from S. circinatum by the shape and size of its chlamydospore-like cells (globose or ellipsoidal, 6.4–14.4 × 4.8–9.6 μm in S. album vs. globose, lobed, or irregular, 4–9 × 3–9 μm in S. circinatum) (Sigler and Wang 1990). Furthermore, S. album differs from S. aurantiacum by its secretion of a pale-yellow pigment (Klingström and Beyer 1965). Additionally, they can be distinguished by their low sequence similarities. Based on a pairwise comparison of ITS and LSU, S. album (ex-type CBS 372.65) differs from S. assmuthi (ex-type PYCC 9837) by 7.4 % (34 / 460 bp, four gaps) in the ITS and 4.2 % (23 / 536 bp, one gap) in the LSU; from S. aurantiacum (ex-type CBS 374.65) by 2.9 % (15 / 521 bp, no gap) in the ITS and 2.5 % (14 / 553 bp, no gap) in the LSU; from S. rodionovae (ex-type 3 C) by 8.6 % (49 / 571 bp, five gaps) in the ITS and 3.7 % (22 / 591 bp, no gap) in the LSU; from S. circinatum (ex-type CBS 654.89) by 6.8 % (49 / 721 bp, five gaps) in the ITS and 5.4 % (67 / 1,234 bp, five gaps) in the LSU; from S. terrigenum (ex-type KNUF- 23-236) by 3.9 % (23 / 580 bp, one gap) in the ITS and 3.3 % (19 / 561 bp, four gaps) in the LSU; and from S. tongrenense (ex-type CGMCC 3.28994) by 6.6 % (36 / 544 bp, six gaps) in the ITS and 2.4 % (14 / 575 bp, one gap) in the LSU. This species demonstrates notable inhibitory effects against various wood-decay fungi, revealing promising biocontrol potential (Klingström and Beyer 1965; Klingstrom and Johansson 1973; Cease et al. 1989). Furthermore, it produces diverse, unique metabolites (such as sorbicillinoid analogs) that exhibit significant inhibitory activity against cancer cells and Aspergillus niger, indicating considerable medicinal potential (El-Elimat et al. 2015).