Colonies conspicuous, effused. Mycelium partly immersed and partly superficial, pale brown, branched and anastomosing, smooth, septate,1.5-2.5 µm thick. Conidiophores setiform, arising from dark brown, smooth, swollen cells of the superficial mycelium, macronematous, mononematous, single, unbranched, erect, straight or flexuous, smooth, septate, dark reddish-brown, paler towards the acute apex, up to 410 µm long, 6.5-10 µm thick. Conidiogenous zone less than half way up the conidiophore, base to conidiogenous zone 70-105 µm, apex to conidiogenous zone 100-245 µm, zone 55-100 µm long, 15-21 µm wide, consisting of a single row of phialides; phialides obscured by a shield of sterile, pale brown, shield cells; each shield cell ca. 4-5 µm long, 2-3.5 µm wide. Conidiogenous cells monophialidic, discrete, cylindrical to lageniform, pale brown, 8-13 µm long, 2.5-3.5 µm wide. Conidia acrogenous, produced in slime and adhering to the fertile part of the conidiophore in a lateral droplet, hyaline, falcate, smooth, medianly 1-septate, (12-) 13-16 (-16.5) x 1-1.5 µm, acute at the apex, obtuse at the base.

On Dracophyllum arboreum Ckn.

Coloniae conspicuae, effusae. Mycelium partim intermum et extermum, ex hyphis pallide-brunneis, ramosis et anastomosantibus, laevibus, septatis, 1.5-2.5 µm crassis. Conidiophora setiformia e cellulis atro-fuscis, laevibus, basi inflata, macronematosa, mononematosa, singula, eramosa, erecta, recta vel flexuoua, laevia, septata, atro rubro-brunnea, apicem versus pallidiora, acuta, usque ad 410 µm longa, 6.5-10 µm crassa. Zona conidiogenosa inframediana, scutelliformis, 55-100 µm longa, 15-21 µm crassa, uno ordine phialidum; phialis scutello cellarum sterilium pallide fusco celata; cellulae steriles ca. 4-5 µm longarum, 2-3.5 µm latarum. Cellulae conidiogenae monophialidicae, discretae, cylindricae vel lageniformes, pallide-brunneae, 8-13 µm longae, 2.5-3.5 µm latae. Conidia acrogenosa, hyalina, adherentia, falcata, laevia, 1 septata, (12-) 13-16 (-16.5) x 1-1.5 µm, apice acuta, basi obtusa. In fohis dejectis epacridaceae speciei Dracophylli arborei Ckn. Holotypus PDD 49399.

The specific epithet refers to the island nature of the type locality.
In a recent account Sutton et al. (1989) provided a key to nine species of Cryptophiale, a tenth species, C. secunda Kuthubutheen & Sutton, having been previously transferred to Cryptophialoidea Kuthubutheen & Nawawi (1987). C. insulare can be distinguished from other species by the structure of the conidiophore apex, size of conidia, and position of the conidiogenous zone on the conidiophore. In conidial size it approaches C. minor Farr, but the conidia of C. insulare are less variable in shape and slightly larger. The conidiophores are also longer, and the conidiogenous zone is in the lower half of the conidiophore, whereas in C. minor it is in the upper half.

Specimen examined: New Zealand, Chatham Islands, Rekohu, Taiko Camp, 8.III.1983, E. H. C. McKenzie (PDD 49399 - holotype).