Part 23

Stem: yellow above and red-brown or orange-tawny below and darkening on bruising; veil forming a delicate fibrillose zone in the upper part of the stem which is soon lost on excessive handling.

Gills: adnate to slightly decurrent, thin and crowded, at first golden yellow, but soon spotted rust colour.

Flesh: yellow and lacking distinctive smell.

Spore-print: rich orange-tawny.

Spores: medium-sized, ellipsoid, finely roughened and deep yellow brown under the microscope, less than 10 µm in length (7-8 × 5-4 µm).

Marginal cystidia: hyaline, flask-shaped with long often slightly irregular neck.

Facial cystidia: similar to the marginal cystidia, but often broader.

Habitat & Distribution: This fungus is found on sticks or twigs or chips of coniferous wood, particularly in plantations.

General Information: Although it has only comparatively recently been recognised in Britain it is very wide-spread. It has been confused with, indeed described under, the name of the less-common fungus Gymnopilus sapineus (Fries) Maire which also grows in conifer woods; it is easily distinguished, however, by its spotted gills. Both the fungi above can be found in books under the old name Flammula, from the bright colour of the caps of many of its constituent members, but Flammula has been used for a genus of flowering plants also and this has precedence.

Illustrations: F 29a; Hvass 152 not very good; LH 175 not very good; NB 109⁶.

Notes on the artificial family group ‘Pleurotaceae’--the Oyster mushrooms

One of the common features of lignicolous fungi is the fact that they lack a distinct stem or if one is present it is attached to one side of the cap, i.e. lateral. However, in the past the correlation of the habitat with lack of stem has induced mycologists to define a single family to include all these forms. After studying the anatomy and microscopic characters this grouping has been found to be entirely artificial and simply reflects how the morphology is tied up intimately with the ecology of a species.

In this one family members of the genera Panus, Panellus, Lentinus, Lentinellus, Crepidotus, Pleurotellus, and Pleurotus have all been grouped together, but some of the genera are more related to the polypores referred to later (p. 135); many of those with brown spores are better placed with Cortinarius and some of those with white or cream-coloured spores are better placed close to Mycena and Tricholoma. This leaves as a residue the genus Pleurotus, a genus which although rather heterogeneous contains one familiar member, i.e. the common Oyster mushroom, Pleurotus ostreatus.

~Pleurotus ostreatus~ (Fries) Kummer

Oyster mushroom

Grows up to 150 mm across.

Cap: flattened, shell-shaped, smooth or slightly cracked, deep bluish grey, gradually becoming brownish with age and finally dark buff.

Stem: absent or very short, passing gradually into one side of the cap.

Gills: white flushing dirty yellow with age, rather distant and deeply decurrent.

Flesh: white, soft and with very pleasant smell.

Spore-print: pale lilac.

Spores: long, hyaline, oblong under the microscope and 10-11 × 4 µm in size.

Marginal and facial cystidia: absent.

Habitat & Distribution: Common, clustered in tiers on stumps, trunks, posts, etc.

General Information: This fungus is not infrequent on old telephone-poles and forms white sheets of mycelium immediately under the bark of fallen trees. Although frequent in autumn it may be found throughout the year and is easily recognised by its size and bracket-like, shell-shaped caps. It surprisingly has a pale lilac spore-print and not as might be expected a white spore-print. In the var. columbinus Quélet the young caps are a beautiful peacock-blue; this variety frequently grows on poplars.

Illustrations: F 125²; Hvass 109; LH 107; NB 125²; WD 31¹.

~Panus torulosus~ (Fries) Fries is a tough, funnel-shaped, yellowish cinnamon fungus with oblong-ellipsoid, small, hyaline spores measuring 5-6 × 3 µm and changing yellowish not bluish grey in iodine solutions.

~Panellus stipticus~ (Fries) Karsten forms tiers of pale cinnamon-brown, more or less kidney-shaped, scurfy caps on old wood and has egg-shaped, hyaline, small spores measuring 4 × 2-3 µm which become bluish grey in iodine solutions.