Olive Shaggy Parasol

Chlorophyllum olivieri is the third of the shaggy parasols split out of the old Macrolepiota rhacodes aggregate, and the one most often overlooked because it lacks the bold contrast that makes its siblings conspicuous. Where C. rhacodes and C. brunneum show dark brown scales against a white ground, this species is drab and monochrome, its scales only a shade or two darker than the greyish, olive-tinged surface they sit on.

The genus is defined by large scaly caps, free gills separated from the stipe by a collar, a movable double ring, and flesh that turns reddish then brown when cut. All of that is present here; only the colour scheme differs. In good light, and especially when fresh and damp, the olive or greenish-grey tone of the cap is unmistakable, but on dried or weathered specimens it fades toward dull brown and the species becomes much harder to place.

It is primarily a woodland fungus, and in much of Europe it is the commonest shaggy parasol found under conifers, appearing in the needle litter of spruce and pine plantations where the more compost-loving C. brunneum rarely goes.

Cap

5-15 cm across, at first ovoid to drum-shaped, then convex and finally flat with a slight central hump. The surface is olive-grey, greyish-brown or drab greyish-fawn, and as the cap expands the skin breaks into fine to medium felty scales that are only slightly darker than the ground colour, giving a subdued, almost uniformly matt appearance. The disc remains as an intact darker olive-brown cushion.

Gills

Free and separated from the stipe by a collar, crowded, broad, white to cream, discolouring dull brownish where bruised or with age.

Stipe

8-15 cm long, pale greyish-brown, smooth, without snakeskin banding. The movable ring is thick and double-edged. The base swells gradually into a club-shaped or slightly bulbous foot with a rounded outline, and it is not finished by an abrupt encircling rim.

Flesh & spore print

The white flesh reddens on cutting, though generally more slowly and less intensely than in Chlorophyllum brunneum, eventually going brown. The spore print is white. No volva or sac is present at the base.

It grows on the litter layer of woodland, with a marked preference for conifers, particularly Norway spruce and pines, but also occurring in mixed and broadleaved woods, in shelterbelts, plantations and shaded parkland. It favours deep needle litter and humus-rich, often somewhat compacted soil, and appears less frequently on compost or garden beds than its relatives.

The species is widely distributed through Europe and reported from North America and parts of Asia. Fruiting runs from late summer through autumn, peaking after the first substantial autumn rains. Fruit bodies occur singly, in scattered troops and sometimes in loose arcs following the spread of the underlying mycelium.

Chlorophyllum olivieri is a litter saprotroph, decomposing fallen needles, leaves and fine woody debris on the forest floor. It forms no mycorrhizal association, so although it is usually found under trees, its relationship is with the litter those trees drop rather than with their roots.

In coniferous plantations, where litter is acidic, resinous and slow to decay, litter-decomposing agarics of this kind perform an important role by breaking down material that many other decomposers handle poorly. The mycelium spreads outward through the litter mat as a slowly expanding front, which is why fruit bodies sometimes emerge in curved lines or partial rings on the woodland floor.

Chlorophyllum rhacodes has a distinctly paler, whitish to cream ground colour with clearly contrasting brown scales and a club-shaped stipe base, and its flesh usually reddens more vividly. Chlorophyllum brunneum shares the coarse brown scaling but is separated at once by its abruptly marginate, rimmed bulb and its preference for compost and disturbed open ground.

Macrolepiota procera is taller and more slender with a much thinner stipe conspicuously patterned in dark snakeskin bands, and its flesh scarcely changes colour when cut. Members of Lepiota in the broad sense are far smaller, and Amanita species with scaly caps differ in having a volva or a distinctly bulbous, sac-like base and gills that are not set on a collar.