Turmalinea Orihara & N. Maek., in Orihara et al., Persoonia 37: 186 (2015)
Etymology: The Latinized name, Turmalinea, refers to tourmaline, the reddish or bluish coloured mineral, referring to the striking colour variety of the fruitbodies.
Basidiomes mostly less than 20 mm diam, solitary to sparse, subglobose to depressed-globose to reniform, rubbery, sessile or rarely with a short stipe at the base, surface smooth to slightly felty, pale pink to pink, or white to brownish white, often turning blue to indigo-blue when rubbed or bruised. Rhizomorphs whitish or yellow to orange. Gleba initially white, then maturing to blackish brown, firm, loculate, of minute irregular chambers and thin tramal plates, chambers arranged somewhat radially near centre. Trama mostly pulvinate, rarely becoming a short stipe, subgelatinous. Columella absent. Peridium thin, up to 450 μm in dried specimens, single- or two-layered, of interwoven to parallel, septate, filamentous hyphae. Subhymenium undeveloped. Basidia clavate to cylindrical, 2–4-spored. Basidiospores statismosporic, ovoid to fusoid, inamyloid, non-dextrinoid, brickred to dark brown at maturity, with 5–10 longitudinal, often branched, costal to irregularly broken ridges up to 3.5 μm high, with or without a hilar appendage. Clamp connections absent in all tissues.
Index Fungorum number: IF803433
Notes: Turmalinea is morphologically characterized by ovoid to fusoid, reddish brown to dark brown basidiospores with 5–10 irregularly furcate, longitudinal ridges, and a cushion-like, subgelatinous sterile base. Two of the four species of Turmalinea have pinkish fruitbodies with yellow to orange rhizomorphs, which are unusual in hypogeous sequestrate fungi. The sister genus, Rossbeevera is morphologically different from Turmalinea in having a sterile base that often forms a short, reduced stipe and paler ellipsoid or fusoid to fusiform basidiospores that have 3–5 longitudinal ridges. Turmalinea also tends to form firm, depressed-globose to reniform basidiomata, which are less common in Rossbeevera. In addition, there is a considerable genetic divergence within the ITS2 minisatellite-like insertion between the two genera, although the insertions are found at the same position in the ITS2 region.
Ecologically, species of Turmalinea occur in broad-leaved forests and are presumably symbiotic ectomycorrhizal associates of trees in the Fagaceae. Although we have not confirmed their ectomycorrhizal status, it is likely that they are mycorrhizal based on the fact that most species in Boletaceae form ectomycorrhizas (Nuhn et al. 2013). While species of Rossbeevera exhibit tropical to temperate distribution and often fruit in summer, Turmalinea species have not yet been found in the tropics and they generally fruit during cooler weather. This might reflect physiological difference in hyphal growth between members of the two genera and, thus, might result in their distributional difference.
Another similar leccinoid sequestrate genus, Chamonixia, also has basidiospores with 6–12 longitudinal ridges, but the basidiospores are generally ellipsoid to broadly ellipsoid (Q = 1.3–1.8). Macroscopically, Chamonixia spp. form light, fragile fruitbodies whereas those in the Rossbeevera-Turmalinea lineage have a more rubbery texture. In addition, the sterile base of Chamonixia fruitbodies is never gelatinized, and often forms a percurrent or branched columella. The genus Rhodactina is a sequestrate member of Boletaceae reported from India and Thailand (Pegler & Young 1989, Yang et al. 2006). The genus is similar to Turmalinea in that the fruitbodies stain reddish to purplish and the basidiospores have 5–10 longitudinal ridges, but is distinctive from Turmalinea in the violet brown to purplish carmine gleba and well-developed (3–5 μm high), unbranched, acute ridges of the basidiospores (Yang et al. 2006; T. Orihara pers. obs.). The ATP6 sequence from Rhodactina incarnata is c. 93–94 % similar to ATP6 sequences of Turmalinea spp., suggesting that they are not members of the same lineage. We obtained an ITS1 sequence of the isotype of R. incarnata (GenBank KC552020), and the BLAST search suggests that it is most closely related to species of Tylopilus. The southern hemisphere genus, Austrogautieria, also has similar basidiospores with eight or more irregularly branched, longitudinal ridges. However, molecular phylogenetic analysis shows that Austrogautieria is a member of Gallaceaceae in the Hysterangiales (Hosaka et al. 2006), and therefore, is phylogenetically distant from Turmalinea. Morphologically, species of Austrogautieria are readily distinguished from Turmalinea by the glutinous spore mass and the presence of a well-developed columella in the gleba.
Type species: Turmalinea persicina Orihara 2015, in Orihara et al., Persoonia 37: 186 (2015)
Turmalinea chrysocarpa Orihara & Z.W. Ge 2015
Turmalinea mesomorpha Orihara 2015
Turmalinea mesomorpha subsp. mesomorpha Orihara 2015
Turmalinea mesomorpha subsp. sordida Orihara 2015
Turmalinea persicina Orihara 2015
Turmalinea yuwanensis Orihara 2015
Orihara T., Lebel T.J., Ge Z., Smith M.E., & Maekawa N. (2016). Evolutionary history of the sequestrate genus Rossbeevera (Boletaceae) reveals a new genus Turmalinea and highlights the utility of ITS minisatellite-like insertions for molecular identification. Persoonia. 37: 173–198