Spores: small, hyaline under the microscope, ovoid, 5-6 × 3-4 µm but usually replaced completely or in part by ovoid, smooth, thick-walled and pale brownish asexually produced spores (chlamydospores) measuring about 15 × 10 µm in size.
Habitat & Distribution: This fungus grows in clusters on old decaying specimens of various species of Russula and Lactarius (Russulaceae)—see [p. 45].
General Information: N. asterophora Fries is closely related and also grows on decaying specimens of various species of Russula, particularly R. nigricans (Fries) Fries. It differs, however, in the cap being fawn-coloured and very mealy when touched; it is recognised by the poorly formed often developmentally hindered gills on which chlamydospores are formed. Unlike the smooth asexual spores in N. parasitica this species has chlamydospores with conical, blunt humps—i.e. star-shaped; asterophora in fact means ‘I bear stars’. These fungi have been associated by some mycologists with the common chanterelle (Cantharellus cibarius Fries, see [p. 162]) in virtue of them possessing reduced fold-like gills. However, the fold-like gills are secondary in nature, correlated with the active production of chlamydospores and the suppression of the formation of basidiospores. The gills are not therefore of a primitive type. The genus Nyctalis is related to fungi such as Tephrocybe palustris (Peck) Donk (see [p. 223]).
There are several rather uncommon ‘agaric-parasites’ of agarics or other higher fungi, e.g. Volvariella surrecta (Knapp) Singer, but their formal description must be left to other more advanced texts. However, the intriguing bolete, Boletus parasiticus Fries, which grows on Scleroderma (earth-balls) in this country has been mentioned and figured previously ([p. 35] & [Plate 64]). It is of interest to note that a close relative of B. parasiticus in Japan lives on another group of Gasteromycetes.
Illustrations: N. parasitica—F 11a; LH 81; WD 257. N. asterophora—LH 81; WD 258.
General notes on Fungicoles
Many beginners are confused on finding specimens which, although appearing agaric-like, are covered in long hairs or irregularly shaped bumps. Indeed many of these abnormalities are true agarics attacked by microscopic fungi, and I know of one textbook on mushrooms and toadstools which includes such an abnormality amongst the discussion on the normal fruit-bodies. Thus Sporadinia grandis Link, which is a primitive fungus, attacks many fungi reducing them to a grey velvety mass of fungal filaments. Specimens of several species of Mycena ([p. 88]) are common in autumn, covered in whiskers with small nobbles on the top. These whiskers are produced by the parasitic Spinellus megalocarpus (Corda) Karsten, another primitive fungus—a phycomycete.
In some wet seasons the orange and green coloured Lactarius deliciosus (Fries) S. F. Gray is to be found contorted and covered in small pinkish to lilac pimples of the ascomycete Byssonectria lactaria (Fries) Petch, and other species of Lactarius are attacked by Byssonectria viridis (Berkeley & Broome) Petch which converts the fruit-bodies into a hardened mass of green tissue. In North America, species of Lactarius are frequently attacked by Hypomyces lactifluorum (Schweintz) Tulasne and the whole fungus is reduced to a contorted acidic-smelling mass of fungal tissue with vivid orange pimples or warts on the outer surface. These parasitic fruit-bodies are eaten as a delicacy in their own right whereas the same consumer will be less enthusiastic about eating the same agaric before it is so deformed.
Boletes particularly B. subtomentosus Fries, B. chrysenteron St Amans and B. edulis Fries are frequently converted into yellow powdery masses due to the production of asexual spores of the fungus Sepedonium chrysospermum Fries; the sexual stage occurs on the remains after they have collapsed into the soil surface—this stage is called Apiocrea chrysosperma (Tulasne) Sydow. Several closely related fungi in the genus Hypomyces also attack agarics.
The yellow pustules found on the spore-bearing surface of the birch polypore Piptoporus ([p. 142]) is Hypocrea pulvinata Fuckel; it is only one of several lower fungi which grow on bracket fungi. The genus Cordyceps has been mentioned previously ([p. 206]) and in the discussion it was indicated that certain hypogeous fungi are attacked by members of this genus.