Orbilia flavida Feltgen, Vorstud. Pilzfl. Luxemb., Nachtr. II

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 : 235-237

Orbilia flavida Feltgen, Vorstud. Pilzfl. Luxemb., Nachtr. II : 43 (1901). ( Fig. 3 )

Apothecia 0.3–0.5 mm in diam., up to 0.2 mm high, scattered, medium yellowish pink (29. m. y Pink) to medium orange yellow (71. m. OY), superficial, disc concave to flat, margin smooth. Asci *(82)88–99(109) × (6.6)7.5–9 μm, †78–91 × 6–7.3 μm; apex thin walled; cylindric-clavate, 32-spored, spores 2–4-seriate, with ascospores upwards oriented near apex and downwards near base, but usually mixed, pars sporifera *40–54 μm; medium long or indistincly bifurcate base. Ascospores *(5.4)6.7–8(9) × 2–3 μm, †6.6–8 × 2–2.5 μm; subcylindrical to clavate, straight to medium curved in the narrower lower part, ends rounded to obtuse; SBs *0.5–0.9 × 1–1.5 μm, lens-shaped, broadly attached to apex. Paraphyses medium to very strongly irregularly clavate to spathulate at apex, 4–6-septate, closely septate near apex; terminal cell *(6.5)7.5–11(14) × 2–4(5) μm, second cell *(3)6–10.5(13) × 2–3(4.5) μm, cell bellow *(9)12–16 × 1.4–3 μm; usually branched above the second cell; exudate 0–1.4 μm thick, pale yellow (89. p. Y), continuous and loosely attached over paraphyses; light gray (264. l. Gray) globose SCBs usually present in apical cell, 0.6–2 μm diam. Ectal excipulum at base and middle flanks of textura angularis to t. globosa, *40–55 μm thick; at margin and upper flank of t. angularis to t. prismatica, *22–40 μm; hyaline, not gelatinized, with a thin continuous light yellow (86. l. Y) layer of exudate at margin, 0.7–1.2 μm thick. Cells of ectal excipulum *9–11(13) × (6.5)7.5–8.7(10.3) μm at base and lower flank, wall thickness *0.3–0.7 μm; *(5)7–9(11.5) × 3–4(5.5) μm at margin, with light gray (264. l. Gray) globose SCBs in cortical cells at margin, 1.5–4 μm diam.

Specimens examined:— SPAIN. Canary Islands: Tenerife, Granadilla de Abona, La Martela, 28°08’29’’N, 16°37’11’’W, 1195 m, typical Canary pine woodland, on wood of a detached branch of Aeonium arboreum , 19 April 2012, L. Quijada & C. Quijada (TFC Mic. 23640!).

Distribution and ecology:— This species has been reported in the northern hemisphere, in Europe ( Germany, Spain mainland). Growing on stems of Clematis and Seseli . Occurring from spring to summer ( ASCOFRANCE 2015, GBIF, Feltgen 1904). By now, this species only has been found once in Macaronesia. It grows on succulent xeric woody branches of Aeonium arboreum in the south slope of Tenerife Island, where it was found at 1195 m of altitude where a dry pine forest develops.

Remarks:— Orbilia flavida was originally described as 8-spored by Feltgen (1904). In the revision of the holotype, one of us (H.B.) found the asci to contain ca. 25–30 spores with lens-shaped spore bodies (Baral et al. in prep.). The measurements given by Feltgen for asci (55–62 × 7–8 μm) and ascospores (4–8 × 2.5–3 μm), are similar to our measurements in the dead state, deviating only in the length of asci. A recent collection was illustrated by Enrique Rubio from Asturias ( ASCOFRANCE 2015), with ascospores 7.2–8.7 × 2.8–3.4 μm.

The morphology of spore bodies and the number of ascospores in the asci of Orbilia flavida distinguish well this taxon from the other species of Orbilia reported until now.

Figures

FIGURE 3. Morphological features of Orbilia flavida. 1. Rehydrated apothecia. 2. Excipular tissues in median section. 3. Living asci. 4. Living paraphyses. 5. Living ascospores. 500 μm= 1b, 1d–f; 100 μm= 1a, 1c, 2a; 50 μm= 2b; 10 μm= 3, 4a–b, 5. Mounted in: H2O= 2a–b, 3, 4a–b, 5. All photos from TFC Mic. 23640.