Amanita constricta — Constricted grisette

Card image cap

Constricted grisette2 with moist, viscid cap, photograph by Ludovic Le Renard.

Card image cap

Constricted grisette6, patches of veil on the cap, photograph by Patrik Inderbitzin.

Non-toxic

Gills: Nearly free, narrowly touching the stem, off-white to pale grey
Spore print: White

Odour: Not distinctive.
Cap: 5–15 cm in diameter, at first convex, then expanding to become flat, sometimes with a small bump in the centre. The colour is grey to brownish grey, often with darker streaks. The surface is viscid when moist. The margin of the cap has distinct and strong grooves, up to 1.5 cm long. A felt-like patch of white or light grey tissue from the universal veil sometimes remains on the cap surface (see 'Additional image').
Gills: Rather crowded, narrowly attached to the top of the stem when young, and then breaking free. The colour is white at first, changing to grey. The edge is grey as well.
Stem: 8–16 cm long x 1–3 cm wide, cylindrical or gradually thickening towards base. Surface white and silky, often covered with flat pieces of grey material. Hollow.
Ring or veil: No ring on the stem.
Cup (volva): The tight cup at the base of the stem is constricted to a narrow sleeve before expanding with a wide flaring margin. Often greyish on the outside. The constriction gives the species its common name.
Spores: 9–13 x 8–11 µm, white, smooth, not reacting with iodine solutions.
Habitat: On the ground with western hemlock (Tsuga heterophylla), Douglas fir (Pseudotsuga menziesii) and fir (Abies spp.) in BC and Pacific northwest, commonly with oak (Quercus spp.) in California1. Ectomycorrhizal.
Geographic distribution: Widespread in coastal and montane forests in western North America, from BC to California.

The death cap (Amanita phalloides) is a highly toxic species that can be mistaken for the non-toxic grisettes. However, the death cap lacks the grooves that radiate around the margin of the western grisette's cap. When young, the death cap can also be distinguished from a grisette by the ring on its stem. However, rings can disappear, warts and other veil parts on the cap surface can be washed off by rain, and the greenish cap of a death cap can change to grey-brown with age.

Among grey to grey-brown Amanita species without a ring on the stem, the constricted grisette (Amanita constricta) stands out because of the strangely shaped cup at the base of the stem. However, if the base of the stem is left behind in the soil, a constricted grisette becomes difficult to distinguish from a western grisette (Amanita pachycolea). The western grisette has a very thick and tall cup that stains brown and like the constricted grisette, its cap is dark brown-grey, and grooved at the margin. It is a more substantial species than the constricted grisette.

None of the species in this ring-less group of Amanita species contain known toxins.

Treatment: Contact your regional Poison Control Centre if you or someone you know is ill after eating grisettes. Poison centres provide free, expert medical advice 24 hours a day, seven days a week. If possible, save the mushrooms or some of the leftover food containing the mushrooms to help confirm identification.

Poison Control:
British Columbia: 604-682-5050 or 1-800-567-8911.
United States (WA, OR, ID): 1-800-222-1222.

1
MyCoPortal. Mycology Collections Portal, <http://mycoportal.org/portal/collections/harvestparams.php> accessed March 2018.
2
Specimen Agaricus constricta UBC F33020, GenBank #MH718233.
3
Trudell, S. & Ammirati, J. F.Mushrooms of the Pacific Northwest. Timber Press, Portland, Oregon (2009).
4
Thiers, H. D. & Ammirati, J. F. New species of Amanita from western North America. Mycotaxon 15, 155-166 (1982).
5
Siegel, N. & Schwarz, C. Mushrooms of the Redwood Coast. A Comprehensive Guide to the Fungi of Coastal Northern California. Ten Speed Press, Berkeley, California (2016).
6
Specimen Amanita constricta UBC F14303, GenBank #AY228351.