A collection from Norway
Pileus: The cap of P. semilanceata is 5 – in diameter and 6 – tall. It varies in shape from sharply conical to bell-shaped, often with a prominent papilla (a nipple-shaped structure), and does not change shape considerably as it ages. The cap margin is initially rolled inward but unrolls to become straight or even curled upwards in maturity. The cap is hygrophanous, meaning it assumes different colors depending on its state of hydration. When it is moist, the cap is ochraceous to pale brown to dark chestnut brown, but darker in the center, often with a greenish-blue tinge. When moist, radial lines can be seen through the cap that correspond to the positions of the gills underneath. When the cap is dry, it becomes much paler, a light yellow-brown color. Moist mushrooms have sticky surfaces that result from a thin gelatinous film called a pellicle. This film becomes apparent if a piece of the cap is broken by bending it back and peeling away the piece. When the cap dries from exposure to the sun, the film turns whitish and is no longer peelable. Gills: On the underside of the mushroom’s cap, there are between 15 and 27 individual narrow gills that are moderately crowded together, and they have a narrowly adnexed to almost free attachment to the stipe. Their color is initially pale brown, but becomes dark gray to purple-brown with a lighter edge as the spores mature. Spore print: deep reddish purple-brown color Stipe: The slender yellowish-brown stipe is 4 – long by 1–3.5 mm thick, and usually slightly thicker towards the base. Veil: The mushroom has a thin cobweb-like partial veil that does not last long before disappearing; sometimes, the partial veil leaves an annular zone on the stipe that may be darkened by spores. The flesh is thin and membrane-like, and roughly the same color as the surface tissue. Taste and odor: farinaceous Stain: All parts of the mushroom will stain a bluish color if handled or bruised, and it may naturally turn blue with age.
Microscopic characteristics In deposit, the spores are a deep reddish purple-brown color. The use of an optical microscope can reveal further details: the spores are oblong when seen in side view, and oblong to oval in frontal view, with dimensions of 10.5–15 by 6.5–8.5 μm. The basidia (spore bearing cells of the hymenium), are 20–31 by 5–9 μm, four-spored, and have clamps at their bases; there are no basidia found on the sterile gill edge. The cheilocystidia (cystidia on the gill edge) measure 15–30 by 4–7 μm, and are flask-shaped with long thin necks that are 1–3.5 μm wide. P. semilanceata does not have pleurocystidia (cystidia on the gill face). The cap cuticle is up to 90 μm thick, and is made of a tissue layer called an ixocutis—a gelatinized layer of hyphae lying parallel to the cap surface. The hyphae comprising the ixocutis are cylindrical, hyaline, and 1–3.5 μm wide. Immediately under the cap cuticle is the subpellis, made of hyphae that are 4–12 μm wide with yellowish-brown encrusted walls. There are clamp connections present in the hyphae of all tissues.
Other forms The anamorphic form of P. semilanceata is an asexual stage in the fungus’s life cycle involved in the development of mitotic diaspores (conidia). In culture, grown in a petri dish, the fungus forms a white to pale orange cottony or felt-like mat of mycelia. The conidia formed are straight to curved, measuring 2.0–8.0 by 1.1–2.0 μm, and may contain one to several small intracellular droplets. Although little is known of the anamorphic stage of P. semilanceata beyond the confines of laboratory culture, in general, the morphology of the asexual structures may be used as classical characters in phylogenetic analyses to help understand the evolutionary relationships between related groups of fungi. Scottish mycologist Roy Watling described sequestrate (truffle-like) or secotioid versions of P. semilanceata he found growing in association with regular fruit bodies. These versions had elongated caps, 20 – long and 0.8 – wide at the base, with the inward curved margins closely hugging the stipe from the development of membranous flanges. Their gills were narrow, closely crowded together, and anastomosed (fused together in a vein-like network). The color of the gills was sepia with a brownish vinaceous (red wine-colored) cast, and a white margin. The stipes of the fruit bodies were 5 – long by 0.1 – thick, with about 2 cm of stipe length covered by the extended cap. The thick-walled ellipsoid spores were 12.5–13.5 by 6.5–7 μm. Despite the significant differences in morphology, molecular analysis showed the secotioid version to be the same species as the typical morphotype.
