Russula aeruginea Lindblad ex Fr. Grüner Birkentäubling, Russule vert-de-gris, Green Brittlegill. Cap 4–9cm across, convex then flattening or depressed, grass-green, sometimes with yellowish or brownish tinges, without any violaceous tints, often with rusty spots, centre usually darker, smooth or radially veined, peeling halfway; margin often furrowed. Stem 40–80 X 7–20mm, white, fairly firm. Flesh white. Taste mild to slightly hot. Gills almost free, usually forking, yellowish-buff. Spore print cream (D–E). Spores elliptic, with rounded warts up to 0.6μ high, some joined by fine lines to form a very incomplete network with 0–2 meshes, 6–10 X 5–7μ. Cap surface hyphae with rectangular, not inflated, supporting cells; cystidia cylindrical to spindle-shaped, without septa. Habitat under birch. Season summer to early autumn. Frequent. Edible. (Never eat any mushroom until you are certain it is edible as many are poisonous and some are deadly poisonous.) Distribution, America and Europe.