Amanita gemmata has a distinct 4 to 10cm diameter, rounded cap on top of a 5 to 13cm tall, .5 to 2cm thick, white stalk. The cap is a creamy light yellowish tan with a darker center and often displays warts that are the remnants of the universal veil. The cuticle of the cap is slighty sticky, especially when moist. The warts can sometimes form a single patch or may be absent as they can disappear with age. The flesh of the cap is white and thick, though just beneath the cuticle the flesh is a light lemon-yellow color. With age, the rounded cap can become plane or even convex. On the lower surface of the cap, the white gills are closely spaced and adnate or free. Spores produced on the gills are white. A partial veil is typically present as a membranous, white, fragile, skirt at the median of the stalk. The universal veil is cottony, white and forms the volva at the tip of the basal bulb.
The fruiting bodies of A. gemmata can be found as a single individual, scattered or in large groups in the woods and along forested paths or roads. In the Pacific Northwest and the Sierra Nevada they are commonly found under coniferous trees from the spring to the fall.
This species is consider poisonous. The toxins produced by A. gemmata are similar to those produced by A. pantherina and A. muscaria, both of which are highly toxic. In the Pacific Northwest, hybrids with A. pantherina have been found.
A synonym of A. gemmata is A. junquillea and the common names include Gemmed Amanita, in reference to the warts on the cap, and Jonquil Amanita.
A. gemmata is similar in appearance to several species of Amanita: A.pantherina, A. flavoconia, A. russuloides and A. breckonii. It differs in that A. gemmata is smaller than A. pantherina, has white veil remnants as opposed to the yellow remnants of A. flavoconia, occurs in the west as opposed the eastern range of A. russuloides and has a single annulus and no rooting base beneath the bulb in contrast to A. breckonii.
Arora, D. (1986) Mushrooms Demystified. Ten Speed Press, Berkeley, CA.
Lincoff, G. (Ed.) (1981) Simon & Schuster’s Guide to Mushrooms. Simon & Schuster Inc, New York, New York.