Data from CBS Aphyllophorales database

SISTOTREMA RADULOIDES (P.Karst.) Donk

Mats white, most isolates immediately around inocula thin to moderately thick, slightly raised to raised, downy to tomentose, then becoming moderately thick to thick, raised, velvety to woolly or woolly-cottony toward margins, other isolates moderately thick, slightly raised to raised, downy to woolly throughout, occasionally zonate, a few isolates sometimes developing white to Cinnamon-Drab, pulvinate sclerotium like structures at 2 wk, by 6 wk white to Ivory Yellow, around inocula thin to moderately thick, appressed and subfelty or slightly raised and tomentose, then becoming moderately thick to thick, raised, woolly to cottony toward margins, often zonate, some isolates producing sclerotium like structures, these Buckthorn Brown to Dresden Brown, pulvinate to gongylodic, often covered with a droplet of clear liquid, deeply pitted when mature; margins even, raised, cottony; odor sweet, fruity at 2 wk, absent, sour, or sweet at 6 wk; no agar discoloration at 2 and 6 wk; not fruiting by 6 wk.

MEA 23-45; 58-88 GAA -, tr-25; 18-30(-46); TAA -, 0-tri TYA -, 25-35; 50-75

Microscopic characters: Marginal hyphae 2-4 µm diam, thin walled, nodose septate, sparsely branched, usually branches arising opposite clamps. Submerged and aerial hyphae 1.5-5 µm diam thin walled, nodose septate, moderately branched, with scattered ampullate hyphae and ampullate clamps at 2 and 6 wk. Conidia (Fig.76a) obovate to pyriform, 4-7 x 2-3 µm, hyaline, thin walled, blastic, borne on simple or rachiform conidiophores, these 15-35 x 0.5-2.5 µm, thin walled, terminal, abundant in aerial mats at 2 and 6 wk. Sclerotium like structures (Fig.76b) composed of (a) internal cells 8-15 x 8-10 µm, thick walled, pale yellow, empty or filled with dense cytoplasm; (b) outer cells similar to internal cells except yellowish brown and often with a single, filamentous, hairlike appendage.

Sexuality: Nine presumptive monosporous cultures of HHB 10204 were paired in all combinations. Two mating types were identified: A1 = 1,4,5,6,12 and A2 = 2,14,15,16. Thus, S. raduloides is bipolar.

Cultural descriptions: Maxwell (1954, p.270); Stalpers (1978, p.145).

Species codes: 1.3c.23.31.d.33.36.37.38.44-45.(50).(53).54.(55). 59.

l.(2).3.7.(23).33.36.38.45.46.54.55. (Nobles 1965, p.1115).

Trechispora raduloides

Key pattern: (1, 2) 1 2 1 (9, 2) 2 1 2 (2, 3) 2 2

The mycelium derived from the germination of a number of spores grows slowly, covering the plate in four to five weeks. The advancing zone is even, narrow, hyaline, and appressed or occasionally with slightly raised aerial mycelium to the limit of growth (Fig. 49). The mat at two weeks is white and raised, with long, cottony-silky fibers radiating from the inoculum (Fig. 49), later becoming appressed and thin farinaceous (Figs. 50 and 5I). Cottony tufts covered with colorless drops of exudate appear, usually at the inoculum, after two weeks, and then in thicker zones which develop across the mat, especially near the edges of the Petri plates, at four weeks (Figs. 50 and 51). These tufts gradually become characteristic, dark brown (7 .5YR4/4), sclerotium-like bodies which are granular and honeycombed in structure and covered with amber drops of exudate (Fig. 51). From the reverse of the Petri dish, the agar under the mat remains unchanged. On gallic and tannic acid agars, diffusion zones are absent. There is a colony of growth 1.0-2.5 cm, in diameter on gallic acid agar and none on tannic acid agar.

The hyphae are thin-walled, hyaline, staining in phloxine, nodose-septate, branched at and between the septa, many enlarged or irregularly swollen at the septa in cultures three weeks old, 1.6-4.5 µm in diameter (Fig. 16). Within a week after transfer of inocula to fresh media and continuing throughout the six weeks of observation, conidiophores develop at the ends of hyphae or, more commonly, as lateral branches, frequently from clamp connections (Figs. I8, 35, and 36). Although the majority of conidiophores begin to produce conidia while still short, others may elongate considerably before doing so and, occasionally, conidium formation is interrupted by an elongation of the conidiophore which, in some cases, may become irregularly swollen and atypical (Fig. 17). The conidia are produced successively in sympodial clusters (Figs. 19 and 39) as a result of proliferation of the conidiophore below each conidium after it is formed to produce a blunt projection on which another conidium is borne, each new conidium assuming a terminal position so that the others appear to have arisen laterally (Figs. 18, 35, 36, and 38). Development continues in this fashion until the conidiophore has exhausted its possibilities, the oldest conidia being cut off at the base of the conidiophore while others are continually forming at the tip, The parent hypha may break apart after the conidia have been formed (Fig. 20). The conidiophores are thin-walled, hyaline, staining in phloxine, the contents somewhat granular at five weeks, no broader than ordinary hyphae, variable in length, occasionally simple-septate, and recognizable, even after the conidia are detached, by reason of their blunt, branching appearance (Fig. 20). The conidia are ovoid, truncate, the attached end blunt and the distal end rounded, thin-walled, hyaline, staining in phloxine, the contents somewhat guttulate in cultures five weeks old, 4.5-9.0 X 1.8-4.5 µm (Fig. 21). The sclerotia are composed of closely packed, pseudoparenchyma-like cells which are hexagonal, thickwalled, the walls of some with pointed seta-like projections, the contents granular, hyaline at first, staining in phloxine, usually brown when mature, occasionally becoming empty, 9.6-14.4 µm in diameter (Figs. 22 and 37).

Mycelium derived from the germination of a single conidium is similar in all respects to that derived from the germination of a number of spores except that there are no clamp connections at the septa. No single basidiospore cultures were available for this species.