Small to medium (occasionally large) agaric, growing on the ground, with a pinkish brown or orange-brown spore print. Pileus often papillate, brown or black, not viscid, velvety. Lamellae free, adnexed or sinuate or notched. Stipe central, velvety. Partial veil remnants absent. Odour strong, like cod-liver oil, linseed oil or cucumber. Spores pale or pinkish, non-amyloid, smooth; germ pore absent. Cheilocystidia large, lanceolate, and with similar cystidia present on all surfaces. Lamellar trama regular. Pileipellis a cutis or a trichoderm. Clamp connections present.

Australian collections of Macrocystidia have the appearance of a Mycena or Marasmius, but they differ in the pinkish brown spore print. Larger forms are known from Europe. Among pinkish brown-spored genera, Macrocystidia is distinguished by the pruinose to velvety pileus and stipe surface, caused by the prominent broadly lanceolate pileo- and caulocystidia. The pinkish brown-spored Entoloma differs further by having angular spores.

Macrocystidia Joss., Bull. Soc. Mycol. France 49: 373, 376. (1934).

One species: Macrocystidia cucumis.

Macrocystidia cucumis (Bull. : Fr.) Joss., Treb. Mus. Ci. Nat. Barcelona, sér. bot. 15: 127 (1934).

Vic. and Tas. (and probably also N.S.W.).

In native forests.

On the ground.

Saprotrophic.

Breitenbach, J. & Kränzlin, F. (eds) (1991), Fungi of Switzerland. Volume 3. Boletes and Agarics 1st part. Edition Mykologia, Lucerne. [Illustration, Description and Microcharacters of M. cucumis from Europe]

Ratkowsky, D.A. & Gates, G.M. (2002), A preliminary census of the macrofungi of Mount Wellington, Tasmania - the Agaricales, Pap. & Proc. Roy. Soc. Tasmania 136: 89–100. [Description of M. cucumis]