Читать книгу Identification of the Larger Fungi - Roy Watling - Страница 31

Cap: width 60–200 mm. Stem: width 10–25 mm; length 40–75 mm.

Description:

Cap: firm, convex usually with a central depression at maturity, dark olive-brown or dark greyish olive with a yellow-tawny, woolly margin when young which soon disappears, and the whole cap becomes sticky with age and turns deep purple when a drop of household ammonia is placed on it.

Stem: short, stout, similarly coloured to the cap except for the distinctly ochraceous apex, slimy and pitted.

Gills: crowded, cream-coloured to pale straw-coloured, but soon spotted with dirty brown, particularly when bruised.

Flesh: white or greyish ochre exuding a milk-like liquid which lacks a distinct smell and is white and unchanging when exposed to the air.

Spore-print: pale pinkish buff.

Spores: subglobose or ellipsoid and covered in a network of strongly developed, raised lines interconnected by finer ones, both of which stain blue-black in solutions containing iodine, generally 8 × 6 µm in size (7–8 × 6–7 µm).

Marginal cystidia: lance- or spindle-shaped and filled with oily contents.

Facial cystidia: similar to marginal cystidia.

Habitat & Distribution: Common in woods and copses, or on heaths especially in boggy places but always where birch is growing.

General Information: Easily recognised by the dull colours and purple reaction with alkali; there is no British species with which L. turpis can be mistaken. The purple reaction is similar to that found in the familiar school laboratory reagent litmus, for the compound found in L. turpis turns purple in alkali and reddens in acidic solutions. First discovered by Harley in 1893 this reaction marked the beginning of a whole series of chemical studies on the agarics which has led to the discovery of many unique compounds.

Illustrations: Hvass 214 (but too green); LH 213; NB 113³; WD 38¹.