Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 68. (Budapest 1976)

Bohus, G.: Agaricus studies, VI.

AGARICUS STUDIES, VI. 47 The problem of Agaricus Iiiteolorufesceus Orton This species of the Silvaticus-group was described in 19(50 and its chief characteristics are that besides the reddening of the flesh also the lower part of the stem becomes yellow. ORTON distinguishes it from A. lanipes, silvaticus and haemorrhoidarius. We succeeded in collecting a similar fungus (Budapest, garden, on ground on a hazel gtump, 25 June 1969, leg. G. BOHUS), of which flesh in pileus and in upper part of the stem ^eddened and the bulb of the stem turned chrome yellow when touched. Description: Pileus 4-5 cm ; convex then expanded ; at first smooth and lighter chocolate brown, then + concentrically with broad fibrillosc scales in chocolate brown colour on lighter ground, centre almost smooth. Stem 3-4 cm long, 5 mm wide, bulb 10 mm; bulbous; above ring whitish, below ring brown fibrillosofloccose; base turning chrome yellow when handled. Ring pendulous, white, edge below brownish villous. Flesh whitish, reddening in pileus and above in stem. Spores 4.9-5.4 X 3.4-4,0 fim. In comparing the two descriptions, there is a difference in the colour and size of the pileus. The colour of the pileus of A. luteolorufescens shows a reddish shade (though during drying a pink shade could be observed also on the fungus from Budapest). The smaller size is due to the poor soil. On the basis of literature and my own observations, the following data can be found regarding the possible turning of yellow of the Silvaticus-group : Agaricus lanipes — HENNIG (1958, p. 146): "Stiel mit rundlicher, fast abgesetzter, oft Chromgelb anlaufender Knolle." The aquarelle shows besides a chrome yellow colour on the cut surface in the basis of the stem. — MOELLER (1950, p. 26) : "the base . .. ends in a white, later yellowish mycelial strand in older specimens the flesh at the base of the stem is yellow." Agaricus haemorrhoidarius

—MOELLER (1950, p. 34): "Flesh . . . sometimes finally ochraceous at the base of the stem." — ESSETTE (1964. Tab. 14): "Chair blanche, parfois ochracée à la fin." On the coloured plate reddening of the stem and the turning yellow of the stem bulb can be seen on the cut surface. Agaricus langei — In case of fungi collected on 31 .May 1970 the flesh in pileus and in upper part of the stem turned red, lower part became yellow. (Spores 8.2-8.8x5.05.3 fim.) On the basis of these examples A. luteolorufescens cannot be regarded as a distinct species and this has been referred to also by ORTON (p. 183): "It remains to be seen if this is really distinct from A. lanipes. . . " Recent occurrences of Agaricus luteo-maeulatus (Moell.) Moell. (Fig. 2) Regarding the species collected in 1937 on one occasion and described in 1951 by MOELLER, there is only one further datum to be found in literature concerning this species (HEINEMANN, 1965). In the autumn of 1974 — the weather being very rainy — a rather rich material could be collected at several sites of Budapest : Kamaraerdő and so the species could be studied more intensively. By using the description of MOELLER, the further statements made on the basis of the above material where put into brakets. The most interesting characteristic feature of the fungus was its rapid colouring into apricot yellow. On several thalli no purplish colour was to be seen on the fruit-bodies. There were thicker and thinner specimen (see drawing, Fig. 2). Pileus 3-4 cm (3-7 cm); semiglobate, then flattened; silky; straw yellow with purplish brown centre, in Latin : medio purpureo-tincto (whitish or cream, with purplish centre or here and there with light lilac, purplish lilae spots or often only cream without any purplish tinge); turning apricot yellow (rusty yellow) on the slightest touch; under the lens minutely flocculose (under the lens short-fibrillose or possibly minutely scaly). At the margin small teeth from the veil (not always). Gills free; crowded, rather broad ; pale (long cream, then possibly rosy), later grey, finally dark. Edge sterile. Stem 3-4 cm X 5-7 mm (4-7 cm X 6-18 mm); cylindrical with a somewhat marginate, suddenly swelling, bulbous base, up to 13 mm broad (or clavate or bulbous, up to 20 mm broad); pithy-hollow; white (whitish), but becoming apricot yellow (rusty