Orbilia dryadum (Velen.) Baral & E. Weber

Quijada, Luis, Baral, Hans-Otto & Beltrán-Tejera, Esperanza, 2016, A revision of the genus Orbilia in the Canary Islands, Phytotaxa 284 (4), pp. 231-262 : 245-247

Orbilia dryadum (Velen.) Baral & E. Weber , comb. & stat. nov. ( Fig. 9 ) MB 813956

Basionym: Orbilia alnea Velen. var. dryadum Velen., Monogr. Discomyc. Bohem. (Prague): 93 (1934)

Apothecia (0.4–) 0.6–1 mm in diam., 0.1–0.2 mm high, scattered to gregarious, pale yellow (89. p. Y) to medium orange yellow (71. m. OY), superficial, disc slightly concave to flat, round to slightly undulating, margin distinct and smooth. Asci *(29)32.5–35(41) × (2.7)3–3.3(3.5) μm, †(21)25–29(31) × 2.3–3 μm; cylindric-clavate, 8-spored, spores (1)2–3- seriate with (2)3–4(6) lower spores inverted (often mixed), pars sporifera *8–16 μm; with a short thin bifurcate base. Ascospores *2.7–3.4 × (0.9)1–1.3 μm, †1.7–3 × 0.8–1 μm; cylindrical, both ends rounded, straight (rarely inequilateral); SBs *(0.4)0.5–0.6(0.7) μm diam., globose. Paraphyses medium to strongly capitate to clavate, 2(3)-septate; terminal cell *(12.5)15–17(19.5) × (2)3–3.5(4) μm, cell below *(4)5.3–6.3(8.5) × 1.4–2.3 μm; not branched; usually without exudate or with a very thin and firmly attached layer (only up to 0.3 μm thick); SCBs globose, light gray (264. l. Gray), one or several large filling the apical cell. Ectal excipulum at base and middle flanks of textura angularis to t. globosa, *(30)67–95(147) μm thick; at margin and upper flank of t. angularis, *(7.7)15–20(29) μm thick; hyaline, not or slightly gelatinized, without exudate. Cells of ectal excipulum *(8.8)14–16(19.5) × (6.7)9.5–11(13.5) μm at base and lower flank, wall thickness *0.2–0.6 μm; *(4)5.5–6.5(9.7) × (3)3.8–4.5(6) μm at margin, without or with sparse light gray (264. l. Gray) globose SCBs in marginal cortical cells.

Previously reported specimens revised and corrected:— SPAIN. Canary Islands: Tenerife, San Cristóbal de La Laguna, Cruz del Carmen, (coordinates, altitude and vegetation no data), on decayed wood, 7 January 1976, R. P. Korf et al. (CUP-MM-000245!). Idem, Las Hiedras, (coordinates, altitude and vegetation no data), on angiosperm wood, 7 January 1976, R. P. Korf et al. (CUP-MM-000273!, CUP-MM-000299!). Idem, Santa Cruz de Tenerife, Roque los Pasos, (coordinates, altitude and vegetation no data), on Morella faya , 10 January 1976, R. P. Korf et al. (CUP-MM-000434!). All erroneously reported as Orbilia epipora in Korf (1992).

2c. cells at base, 2a. section at lower flank. 3. Living and dead asci. 4. Dead and living paraphyses. 5. Living ascospores. 500 μm= 1c–n;

100 μm= 1a–b; 50 μm= 2a; 10 μm= 2b–d, 3a–d, 4a–c, 5a–c. Mounted in: CR = 3c, 4a; H 2 O = 2a–d, 3a–b, 4b–c, 5a–c; MLZ = 3d. Photos: TFC Mic. 23601= 1h–j, 3b, 5a; TFC Mic. 23627= 1k–n, 2a, 4b, 5c; TFC Mic. 24109= 1c–g, 2b–d, 3a, 3c–d, 4a, 4c, 5b; TFC Mic. 24302=

1a–b.

Additional specimens examined:— SPAIN. Canary Islands: Tenerife, El Rosario, Montaña Grande, 28°25’51’’N, 16°23’05’’W, 1199 m, humid Canary pine woodland, on wood of Adenocarpus foliolosus , 3 October 2012, L. Quijada & C. Quijada ( TFC Mic. 23601!). Idem, 20 September 2013, L. Quijada & C. Quijada ( TFC Mic. 24302!). La Laguna, Anaga Rural Park, near Las Mercedes, Hija Cambada, 28°31’44’’N, 16°17’10’’W, 845 m, humid evergreen laurel forest, on wood of Ocotea foetens branch, 18 April 2013, L. Quijada & C. Quijada ( TFC Mic. 24109!). La Matanza de Acentejo, Montaña la Morra, 28°24’40’’N, 16°24’59’’W, 1521 m, humid Canary pine woodland, on wood of Chamaecytisus proliferus branch, 3 October 2012, L. Quijada & C. Quijada ( TFC Mic. 23627!). Idem, on wood of Adenocarpus foliolosus , 20 June 2014, L. Quijada & C. Quijada ( TFC Mic. 21216!). Santa Cruz de Tenerife, Anaga Rural Park, Piedra Chinobre, 28°33’30’’N, 16°10’29’’W, 901 m, Erica platycodon ridge-crest evergreen forest, on wood of Erica platycodon , 20 January 2011, L. Quijada, E. Rodríguez & J. Díaz-Armas ( TFC Mic. 23057!, 23204!).

Distribution and ecology:— This species had been only reported from the type collection in the northern hemisphere, in Europe ( Czech Republic). Growing on wood of Tilia . Occurring in autumn ( Velenovský 1934). O. dryadum was found to be plurivorous in Europe and Macaronesia on rotten hygric wood of various angio- and gymnosperms, occurring throughout the year (Baral et al. in prep., present study).

Remarks:— Orbilia dryadum is characterized by cylindrical, almost straight, small, comparatively wide ascospores with globose SBs very close to the apex, and medium to mostly strongly capitate paraphyses without or with sparse exudate. The similar O. epipora is separated by slightly longer and narrower spores, comparatively shorter asci, without ever presenting strongly capitate paraphyses (in the living state), consistently white apothecia, which often grow densely gregarious over large areas (a feature never seen in O. dryadum ), and in the Dactylella -like anamorph with distinctly smaller, especially narrower conidia with less septa (Baral et al. in prep.).

Velenovský gave in 1934 a very short documentation of Orbilia alnea var. dryadum . The revision of the holotype (PRM 151745) by one of us (H.B.) revealed cylindric ascospores (†2.7–3.8 × 1–1.2 μm) and 8-spored asci (†25–29 × 2.8–3.3 μm) (Baral et al. in prep.). These characters match with the description present here, except that the dead spores were found to be distinctly smaller and the dead asci slightly narrower.

Figures

FIGURE 9. Morphological features of Orbilia dryadum. 1. Fresh apothecia. 2a. Excipular tissues in median section, 2b. section at margin,