L. hypophyllum; pyreniis minimis punctiformibus, sparsis, nervisequiis, innato-protuberantibus, late ellipticis, utrinque rotundatis, atris, opacis, rigidulis, sub lente subtiliter, ex epidermide, striolatis, rima angusta subflexuosa hiantibus, subinde depressis, canaliculatisve ; ascis paraphysibus paullo longioribus, sporidiis plerumque rectiusculis.

Hysterium breve: peritheciis brevibus, ellipticis, nigris, prominulis, rima angustissima, ascis linearibus elongatis. Berkel. fung. in Cryptog. antart. 3. p. 62. tab. 68. fig. 8. bona.

Ascocarps in vertical section initially subepidermal, epidermal cells becoming filled with fungal tissue as ascocarps mature. Hymenium surrounded by layer of vertically-oriented, thin-walled, hyaline, cylindric cells. Upper wall 20-25 µm wide, of dark brown, thick-walled cells, with a narrow extension, comprising very dark tissue, extending across top of hymenium.

Paraphyses 1-2 µm diam., undifferentiated or slightly swollen at apex, extending 10-15 µm beyond asci. Asci 110-130 x 6-7 µm, cylindric, apex rounded, wall not thickened, 8-spored. Ascospores 60-70 x 1.5-2 µm, 0-septate, with indistinct gelatinous sheath.

The type specimen of this species (K) is fragmentary. Vertical sections were made from part of one ascocarp from the type. Ascocarp structure was typical of L. multimatricum. Asci, ascospores, and paraphyses were not clearly seen. Berkeley (in Hooker 1847) provided illustrations, but no measurements of the hymenial elements.

Two recent collections from New Zealand, one on Uncinia (PDD 46121), and one on Gahnia (PDD 37127) have the same kind of ascocarp structure as the type of L. breve. The asci and paraphyses from these collections match the illustrations of Berkeley, and as L. breve was originally described from an Uncinia sp., it is assumed that the recent collections represent L. breve. The following description is based on the recent New Zealand collections.

L. breve was placed in synonymy with L. gramineum by Tehon (1935), however the two fungi differ in ascocarp structure and in ascus width.

See also notes under L. multimatricum.