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Summary: The Amanita constricta group is characterized by tall slender stature, gray markedly striate cap, absence of partial veil and ring, presence of constricted volva with flaring upper border, and when moist, a characteristic reddish staining of the universal veil. The term 'grisette' refers to Amanitas with tall, slender stature, striate cap margin, and saccate (or constricted saccate) volva, but without a partial veil or annulus. Which of the grisettes occur in the Pacific Northwest is uncertain although they are common as a group: The volva in the A. constricta group is firmly attached partway up the stem and flares open at the top, whereas in A. pachycolea, A. 'alba', A. vaginata, and presumably the fulvous-colored Amanita that resembles A. vaginata differ from the A. constricta group in that the volva on A. vaginata is attached only at the bottom of the stem. The Amanita ceciliae group does have a constricted volva like Amanita constricta (see SIMILAR). There is also a species or group of species designated "NW 4" in Lindgren(1) which keys out close to A. pachycolea but has pale tan to light brown cap, and the volva may be constricted. A. constricta sensu lato has been reported from WA by O'Dell(1) and Edmonds(1) and collections from BC are deposited at University of British Columbia. Amanita constricta was described from CA. Tulloss(6) examined collections from OR and CA.
Cap: 4-13cm across, oval becoming convex or flat to slightly umbonate; color beneath the veil tissue (if present) gray, or sometimes brownish gray; "smooth or covered with a large patch of white to buff or grayish universal veil tissue which often separates later into several pieces", slightly viscid when moist, conspicuously striate, (Arora), 5-13cm across, convex becoming flat-convex to flat, eventually somewhat umbonate to umbonate, margin decurved [downcurved] at first, soon flat to wavy, slightly uplifted when old; 'gray to brownish gray, "pale mouse gray" to "light drab gray", to "drab" to "hair brown", disc at times as dark as "chaetura black", furrows of striations a paler shade of pileus color', often with inconspicuous, radial, dark streaks, viscid when moist, disc bald or covered with a patch of universal veil tissue, the patch membranous, somewhat fibrillose, typically less than 0.1cm thick, when old often breaking at the edges into smaller plaques, 'colored white to buff to "smoke gray", or sometimes with pale vinaceous shades, bruising salmon color when wetted, slowly returning to white', margin entire becoming rimose [cracked], strongly sulcate [grooved] to tuberculate-striate, striations 0.5-1.5cm long, (Thiers)
Flesh: fragile, rather thin; white to grayish, (Arora), thin, 0.5-1.7cm thick at disc, thinning toward margin, fragile; gray to drab next to cap surface, white below that, sometimes becoming very faintly pinkish when exposed, especially when young, (Thiers)
Gills: adnate to adnexed or free, close; white or grayish, (Arora), adnate to decurrent by a short hook when young, becoming free, close to crowded, subgills in several series, gills moderately broad; 'white at first becoming gray, "smoke gray" to "pallid mouse gray" to "pale drab gray"', edge usually gray; edge fimbriate [fringed], (Thiers)
Stem: 10-16cm x 1-2cm, equal or widening downward, stuffed or hollow when old, "smooth or more often belted with numerous delicate grayish scales", (Arora), 10-16(20)cm x 0.7-1.7cm at top, "equal or tapering downward, not bulbous", stuffed becoming hollow, no ring present; white with gray scales that darken when bruised; silky fibrillose, at the top with longitudinal striations or pruinose resulting from contact with the gills, becoming appressed-fibrillose in lower part, on expansion of the cap the outer layer of stem often rupturing and forming rings of appressed-fibrillose scales, (Thiers), VOLVA membranous universal veil, "gray to white or buff, often bruising reddish when wet", forming a constricted, flaring sac-like volva (i.e. lower part of volva constricted around stem, upper margin flaring outward) which may disintegrate when old, (Arora), "membranous, tightly adhering and apparently interwoven with surface layer to lower one-third to one-half of the stipe, then developing a flaring free margin resembling an annulus, collapsing with age, white to pale buff or pale yellow, bruising reddish when wet, then fading", (Thiers)
Veil: ring absent (Thiers)
Odor: not distinctive (Thiers)
Taste: not distinctive (Thiers)
Microscopic spores: spores 9.5-13 x 8-10.5 microns, elliptic to nearly round, smooth, inamyloid, (Arora), spores 9.6-12.8(14.4) x 8-10.4(11.2) microns, round to nearly round to obovoid, smooth, inamyloid, thin-walled, colorless in KOH, apiculus strongly developed, eccentric; basidia 4-spored, occasionally 1-spored and 2-spored, 56-70(77) x 11-16 microns, clavate, colorless in KOH; pleurocystidia and cheilocystidia not differentiated, margin cells of gills abundant to absent, 30-40 x 15-22 microns, saccate to spheropedunculate, colorless in KOH; clamp connections absent, (Thiers)
Spore deposit: white (Arora, Thiers)
Habitat / Range
single to scattered or in groups in woods, especially with oaks, (Arora), in "coastal forests where it occurs mainly under hardwoods such as coastal oaks and madrones, but it has, on occasion, also been found under Douglas fir", (Thiers, for California), fall
The Amanita ceciliae group has a constricted volva but differs from the Amanita constricta group in having a floccose (not membranous) volva, lacking a basal bulb, and having volvar remains that are much darker than those on the A. constricta group. The A. constricta group, like the A. ceciliae group, has a volva that is constricted forming a belt of grayish tissue (often fragmented) around the stem base, but A. constricta often has large patch on cap and it has elliptic to nearly round spores (9.5-13 x 8-10.5 microns) as opposed to round spores (10-14 microns) for A. ceciliae group. Amanita pachycolea and Amanita vaginata do not have a constricted volva.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2019. E-Flora BC:
Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for
Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
21/10/2019 9:22:53 PM
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