Fig. 14.

Helminthosporium quercinum, sexual morph. A, B. Ostioles. C–H. Ascomata in horizontal (C–F) and vertical (G, H) section, surrounded by a well-developed pseudostroma and subiculum (E–H). I, J. Peridium and pseudostroma in section. K. Peridium of ascoma basis in section. L. Pseudostroma with verrucose marginal cells. M–O. Verrucose subicular hyphae. P. Ascus with vital ascospores. Q. Pseudoparaphyses. R–M1. Mature ascospores surrounded by gel sheath (R–J1. vital, K1–M1. dead; in K1–M1 showing widely disposed striae in the ascospore wall). All in water, except I–K, N, O, L1 in 3 % KOH. A–E, G–N, P, X–C1, K1, M1. WU 38876 (holotype); F, O, L1. IMI 219012; Q. WU 38874; R, S. WU 38879; T–W. WU 38878; D1–J1. WU 38880. Scale bars: A = 500 μm; B–E, G, H = 200 μm; F, I = 100 μm; J–O, Q–M1 = 10 μm; P = 20 μm.