Black mycelium

Watery soft rot caused by S. sclerotiorum and S. minor often develops on tubers that appear sound at harvest but subsequently succumb in storage (Gaudineau and Lafon, 1958). The tubers become covered with a dense white mycelium and irregular sclerotia, which progress from white to dark brown or black. Though storage at low temperatures repressed development, S. sclerotiorum can cause serious losses at low temperature (Johnson, 1931). 

Rhizopus nigricans (Mucor stolonifer), commonly known as Black Mold or Black Bread Mold, is frequently found on bread, jellies, syrups, acetic pharmaceutical extracts and other substrata, where it forms a dense thready mycelium bearing numerous black tiny spore cases. The source of this mold is the spores, which are found in the air or water with which the attacked substratum is... 

C. panicoidearum was described from Isachne globosa O. Kuntze in Japan (Tanda and Harada, 1989). Sclerotia are dark purple or black, oblong, ovoid or obclavate, somewhat flattened and usually straight, 1.7-6.6 X 0.8-2.5 mm. Stipes are blackish purple with a tuft of mycelium at the base. Capitula are subglobose or depressed globose, darker than the stipe in color, with dark purple perithecial ostioles, 0.3-1.1 X 0.3-1.6 mm. Perithecia are oblong or ovoid, 219-312 X 122-194 uliu. Asci are 126-214 X 2.5-3.5 xm with ascospores 95-193 xm. Conidia are ellipsoid or ovoid, 2.5-5.9 X 1.6-2.5 xm (Fig. lq). 

Blue-stain is very severe on the white pines and is particularly noticeable because of their white wood. Plate 1, left part, shows a section from a sugar pine rib web in which the sapwood is stained to some extent. The small, darker, bluish black spots are the ends of the medullary rays, in which, as before stated, the fungous mycelium is moBt abundant. The longer streaks are the resin ducts. 

Fig. 4.4. Black sclerotia and soybean seed covered with mycelium of Sclerotinia sclerotio-rum. (Photo courtesy of D. Mueller)...

A well-researched booklet appeared in 1968, with procedures for synthesizing psilocyn [sic] and growing mycelium of psilocybian mushrooms for extraction (Brown 1968). This pioneering booklet was illustrated with a water-color painting of Psilocybe hoogshagenii, rather fantastically copied from a black-and-white photograph of dried specimens in the mycological literature (Heim Wisson 1958). 

Macroscopic Appearance A rapidly growing rich gray black to blackish mycelium. Alternaria first appears as scattered blackish spots in the spawn jars, soon spreading and overwhelming The mushroom mycelium. On agar, it resembles a black Penicillium- ke mold. 

Microscopic Characteristics Spores distinctively longitudinally ribbed with nerve-like ridges, produced eight at a time (rarely four) in a sac-like organ called an ascus which is in turn enclosed within a ball-like perithecium that can be dark brown to black to pink in color. Its mycelium is usually pigmented, a feature influenced by the type of habitat. Its imperfect form, Monilia, consists of a simple mycelia network which branches. Monilia segments at the tips from which ellipsoid, oval or globose spores are formed in short chains from the terminal ends. Monilia spores are frequently pinkish. 

Macroscopic Appearance Whitish at first, then grayish, soon dark brown or jet black with spore production. As Torula matures, the mycelium becomes covered with a mass of spores that give it a soot-like appearance. On compost, this fungus appears similar to Humicola. 

The cultured mycelium of the ascomycete Cordyceps ophioglossoides rapidly turns greenish black on exposure to alkali. The pigments responsible for this colour change have been isolated and characterised,... 

Aspergillus begins as a white mycelium similar to Penicillium, but as conidia mature, the colony develops a black coloration. Microscopically, conidiospores are borne in chains at the apex of flask to knob-shaped vessicles called sterigmata. A. niger plays an important role in rot, particularly in warm climates. This feature has led to its description as the hot weather mold. Aspergillus, Rhizopus, and Acetobacter represent the important members the summer bunch rot complex. 

Asexual reproduction of moulds normally occurs by means of spore formation. From the mycelium special branches reach up into the air. At the tip of these conidiophores the spores (conidiospores) are formed on a genus specific structure. The colour of mould colonies on solid substrates (e.g., different shades of green for Penicil-lium species, or black far Aspergillus niger) is entirely due to the massive production of these conidiospores. 

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