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Amanita magnivelaris Peck
"Great Felt Skirt Destroying Angel"

A. magnivelaris A. magnivelaris

Technical description (t.b.d.)

BRIEF DESCRIPTION: The following is based on original description of Peck (1898), a modern description by Lamoureux and Neumann (1990), and the extensive notes on specimens of the species collected near Ithaca by G. F. Atkinson in the early 20th Century (now in the Cornell University Plant Pathology Herbarium, originally misdetermined as A. elliptosperma G. F. Atk.).  In addition a collection of R. Singer from Wisconsin (now in the Farlow Herbarium) and several collections sent from Canada by M. Yves Lamoureux were of great value.

The cap is 40 - 127 mm wide, white to cream or yellowish white, viscid when moist, convex at first, later planar and eventually concave in age.  It occasionally bears a membranous patch of the volva.  Infrequently the entire free limb of the volva is present on the cap in a group of discontinuous patches.

The gills are distinctly attached to the stem or free, close, white, and sometimes have faint pinkish tint.

The stem is 70 - 178 × 7 - 12.5 mm (length includes bulb), white, subcylindric or narrowing upward, and floccose to somewhat scaly.  The bulb at the stipe's base is usually greater than 20 mm wide and tapers to a point on its bottom.  The very broad ring is felted rather than membranous, unusually thick for species of sect. Phalloideae, white to cream to yellowish cream, floccose on the bottom side, and superior to apical.  The volva is limbate and has membranous limbs that are white to grayish and markedly more distant from the stem than in A. bisporigera G. F. Atk.

The odor is not reported.

The spores measure (7.2-) 8.2 - 10.8 (-12.5)  × (5.2-) 5.8 - 7.8 (-9.2)  µm and are broadly ellipsoid to ellipsoid to (occasionally) elongate and amyloid to strongly amyloid.  Basida lack clamp connections at their bases as appears to be true throughout sect. Phalloideae.

The cap of A. magnivelaris does not normally turn yellow in response to KOH solution.  However, some specimens have a tendency to turn yellow when bruised or after some period of exposure (possibly the "yellowing syndrome"?) and these specimens will give some yellow reaction when tested with KOH.  Some authors have called these yellowing specimens "A. decipiens sensu Lamoureux."  (See the key to the taxa of sect. Phalloideae in North America, cited below with link.)

This species is DEADLY POISONOUS.

Amanita magnivelaris was originally described from Long Island, New York.  It is known with confidence from southeastern Canada and the adjacent states of the US (Wisconsin to New York). This species is solitary to subgregarious to gregarious in sand or sandy soils (e.g., sandy loam).  It is found under oak (Quercus) or in mixed woods of pine (Pinus), Canadian Hemlock (Tsuga canadensis), Beech (Fagus grandifolia) and oak as well as under Birch (Betula).  Amanita magnivelaris is not commonly collected and probably should be considered rare.

The pointed base of the stem's bulb does not separate this species from members of the A. elliptosperma "group."  The spore size and shape is not much help either; however, the very large, felted ring and the floccose stem are very distinctive characters that are useful in the field and in the laboratory.

My understanding of the present species owes a great deal to an extensive correspondence over many years with M. Yves Lamoureux (Prov. Quebec, Canada) who persisted in his labors until I finally "got it."  Thank you, Yves.

The reader may want to examine the recently revised key to the taxa of sect. Phalloideae in North America. -- R. E. Tulloss

Photos: G. F. Atkinson (left, New York, USA) used by permission of Dr. Kathie Hodge, Director, Plant Pathology Herbarium, Cornell University.  Y. Lamoureux (right, Prov. Québec, Canada). 

[Note: G. F. Atkinson photos and images from other sources may be located from the Photographic Collections page of the Cornell Plant Pathology Herbarium.]

[Note: A superb illustration of the present species can be found on the web site of the Cercle des Mycologues de Montréal (here).]

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Last changed 9 October 2009.
This page is maintained by R. E. Tulloss.
Copyright 2006, 2008, 2009 by Rodham E. Tulloss.
Photograph of New York specimen is the property of Cornell University and is used by permission.
Photograph of Quebec specimens is copyright by Cercle des Mycologues de Montreal.