Ascocarps intraepidermal. In vertical section upper stromatal layer 20-80 µm wide, becoming wider around opening. Wall composed of dense, black tissue around opening ascocarp, otherwise of brown to pale brown, pseudoparenchymatous cells, 4-7 µm diam. Lip cells cylindric, hyaline, becoming dark brown, embedded in gel. Short, hyaline periphyses often present, lining the upper wall. Lip cells and periphyses often elongating and becoming septate, forming an extensive excipulum-like layer in older ascocarps. Lower stromatal layer joining the upper, 8-15 µm wide, of 2-3 layers of thick walled, dark brown cells, 2.5-4 µm diam. Subhymenium 19-30 µm wide, of hyaline, thin walled cells, 3-6 µm diam.

Paraphyses 2-2.2 µm diam., becoming slightly swollen at apices, 3-4.5 µm diam., extending 10-20 µm beyond asci. Asci subclavate, gradually tapering toward the base from near the apex, tapering at top to a more or less acute apex, uniformly thin walled, 104-142 x 7.5-11 µm, non-amyloid, 8-spored. Ascospores acicular, 41-60 x 2.2-3 µm, tapering slightly to the basal end, 0-septate, poorly developed gelatinous sheath.

ETYMOLOGY: lauraceus; refers to host plant family.

NOTES: C. lauraceus is more or less intermediate between C delta (Kunze) Saccardo, and C. dentatus (Kunze & Schmidt:Fries) Saccardo, two species discussed by Sherwood (1980). All three species have subclavate asci and paraphyses with slightly swollen apices.

C lauraceus agrees well with C. delta (Azores, Sao Miguel, Hickling Park, on Lauraceae, R. P. & N. Korf, L. M. Kohn, A. Y. Rossman, 5.IV. 1978 CUP-MM1845; Canary Is., La Palma, Los Tilos, on Ocotea sp., R. P. Korf, W. C. Dennison, L. M. Kohn, M. A. Sherwood, 14.1.1976 - CUP-MM654; ibid., on Laurus sp. - CUP-MM647; Madiera, Chao dos Louros, on Lauraceae, R. P. & N. Korf, L. M. Kohn, A. Y. Rossman, 26.IV.1978 - CUPMM2455) in possessing lip cells, in lacking pycnidia, in ascus size, and in being found exclusively on Lauraceae. It differs from C. delta in having periphyses which develop into an excipulum-like layer, and in having significantly shorter and broader ascospores (41-60 x 2.2-3 µm versus 80-100 x 2 µm).

The ascospore length of C. lauraceus matches that of C. dentatus (Sydow, Mycotheca Germanica 1249- PDD; USA, Oregon, on Castanopsis sp., Sherwood, 8.Vlll. 1978 - FH; Ellis and Everhart, North American Fungi 3336, on Berberis sp. - PDD). However, C. dentatus lacks lip cells, is associated with pycnidia, has shorter asci (80-105 µm), and, according to Sherwood (1980) is found on a wide range of host plants.

This is the only Coccomyces species found on Lauraceae in New Zealand.