Colonies on CMA effuse, becoming lanose to floccose, with smoke grayish flocci at the center, rosy vinaceous to pale vinaceous or vinaceous Buff, attaining 26 mm diam at ±23 C in 21 days, regular,.sporulating abundantly after 15 days; reverse pale vinaceous to vinaceous Buff. Colonies on DWA effuse, hyaline to subhyaline or dingy white, 10 mm diam in 21 days, with no aerial mycelium, producing abundant conidiophores after 7 days; reverse subhyaline to dingy white. Mycelium mostly immersed, partly superficial, composed of hyaline to subhyaline, pale olivaeous or pale brown, septate, smooth, thin-walled, branched hyphae, 1.2-2.5 µm wide. Conidiophores macronematous, mononematous, mostly unbranched, rarely branched below the fertile part, straight or flexuous, subhyaline to pale brown or olivaceous brown toward the upper part and commonly becoming lighter towards the base, sparsely septate, smooth, 54.7-167.2 µm long including conidiogenous cells, (2.2-)2.8-4.3(-5) µm diam at the base, (1.9-)2.2-4.3 µm at the apex; basal cell often swollen to 6-9.2 µm. Conidiogenous cells polytretic, terminal, intercalary, proliferation holoblastic or enteroblastic-sympodial, polyblastic, rarely monoblastic on branched conidiophores, cicatrized, pale brown to olivaceous brown. Conidia solitary, dry, acropleurogenous, partly embedded in the conidiogenous cell wall, pale yellow, pale golden brown, or olivaceous brown, straight, sometimes curved, cylindrical to clavate, obovoid, smooth (1-)2-4 (mostly 4) distoseptate, basal cell commonly cut off by darker septa and slightly bulging, apex obtuse, base mostly truncate obconic with a distinctly protruding hilum up to 2 x 2.2 µm, (9.8-)15.2-27.3 x (6.8-)7.6-9.9 µm.

Conidia are 1-4 septate and not more than 27.3 x 9.9 Am in size, which readily distinguishes this species from all other Exserohilum species (Sivanesan, 1984, 1987; Alcorn, 1986, 1988; Muchovej and Nesio, 1987). The conidial configuration of this fungus resembles that of two varieties of Sporidesmiella hyalosperma (Corda) Kirk (1982), where the conidial ontogeny, secession and proliferation are heterogeneous. Kirk delimitted one variety, S. hyalosperma (Corda) Kirk var. hyalosperma, and 5 other species of Sporidesmiella Kirk, by the monoblastic percurrently proliferating conidiogenous cells which produce holoblastic conidia with basal textura truncata, seceding often by breaking or tearing from the apical outer wall of the conidiogenous cell. The second variety, S. hyalosperma var. novae-zelandiae (= Sporidesmium hyalospermum var. novae-zelandiae) was delineated by conidia with truncate bases produced on polyblastic, sympodially proliferating conidiogenous cells (FIG. 5), but the figures of Hughes (1978, Fig. 45a, b) and Zhang et al. (1983, Fig. 2) clearly show that the conidia possess truncate obconical bases. However, our observations during this study showed that the bases of the conidia are embedded in the cicatrices of a polyblastic, enteroblastic-sympodial conidiogenous cell. Conidia secede schizolytically and are usually truncate obconical at the base with a pro-trading hilum. This pattern of development appears much closer to the existing circumscription of Exserohilum (Sivanesan,1987; Alcorn, 1988) than to Sporidesmium Link: Fr. and Sporidesmiella. Both of the latter genera are characterized as having mainly annellidic conidial development (Ellis, 1971; Carmichael et al., 1980; Kirk, 1982). Our isolate from grass debris also reinforces the affinity of this fungus with other known Exserohilum species since most are graminicous. In our opinion, conidial shape and septation should not be taken as a generic delimitation since there are many hyphomycetous fungi which share a common conidial morphology. Furthermore, conidial morphology can differ considerably even within a single species. Also, we doubt that S. brachysporoides Zhang & Kendrick, which produces conidia on sympodial, denticulate conidiogenous cells, belongs to the Sporidesmiella, but lack of an authentic specimen at this time precluded us from a final judgment.