Amanita petersenii - Amanitaceae.org - Taxonomy and Morphology of Amanita and Limacella

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name	Amanita petersenii
name status	nomen provisorum
author	Tulloss & Kudzma
images	1. Amanita sp-S06, longitudinal section of stipe base and volva, Blue Valley, Macon Co., North Carolina, U.S.A.
intro	The following material is based on original research of R. E. Tulloss.
cap	The slightly flat, brownish gray cap is 78 mm wide and has a brown center with a broad rounded knob. The cap appears streaked with fine hair-like lines for most of its radius. The cap's flesh is white with a thin gray region below the cap's skin (10x lens required). The cap is 4.5 mm thick above the stem and thins evenly for most of its radius and then is reduced to a membrane the rest of the way to the grooved edge. The marginal grooving about half-way from the cap's edge toward its center.
gills	The free gills are 4.5 - 5.5 mm wide with a descending line on the upper stem. The edge of the gills bear what appear to be fine hair-like projections. The short gills are cut off squarely.
stem	The pale cylindric stem is 140 x 90 mm and is decorated with pale gray powder towards the flaring top, with darker fibers and narrow gray patches below. The stem is pale grayish-white and is unchanging when cut or bruised. No ring is present. The stem is stuffed with white cottony material that bruises yellowish in a central cylinder 3 mm wide. The flimsy, crumbly, sac-like volva is white in its lower half and is gray in its upper half.
odor/taste	The odor is reported to be "faintly fungoid." The taste was not recorded.
spores	The spores measure (9.1-) 9.5 - 10.8 (-11.0) × (8.0-) 8.5 - 10.0 (-10.5) µm and are inamyloid and subglobose to broadly ellipsoid. Clamps are probably lacking at bases of basidia.
discussion	This species was found growing solitary in North Carolina in a dry coarse mixed forest made up of mainly Eastern White Pine (Pinus strobus), Eastern Hemlock (Tsuga canadensis), Maple (Acer sp.), and Rhododendron. This taxon has at least a superficial affinity to A. submembranacea of Europe or to the subarctic A. mortenii or to the North American A. sinicoflava.. Amanita petersenii was formerly called A. sp-S06 on this site.—R. E. Tulloss and N. Goldman
brief editors	RET

name

Amanita petersenii

author

Tulloss and Kudzma

name status

nomen provisorum

GenBank nos.

Due to delays in data processing at GenBank, some accession numbers may lead to unreleased (pending) pages. These pages will eventually be made live, so try again later.

accession	locus	voucher	source



MK926746	nrLSU	10.vii.1990 Ronald H. Petersen s.n. [Tulloss 7-10-90-D] (RET 147-9)	L. V. Kudzma
MK926747	nrITS	10.vii.1990 Ronald H. Petersen s.n. [Tulloss 7-10-90-D] (RET 147-9)	L. V. Kudzma

intro

Olive text indicates a specimen that has not been thoroughly examined (for example, for microscopic details) and marks other places in the text where data is missing or uncertain.

The following material is based on molecular studies of Dr. L. V. Kudzma and other original research of R. E. Tulloss

pileus

78 mm wide, brownish gray (browner than 10YR 6/2) with brown disc (slightly darker and browner than 5E4), virgate for most of radius, subplanar, umbonate, tacky; context white with thin grayish line below pileipellis (10× lens), 4.5 mm thick above stipe, thinning evenly for 80% radius, then membranous to margin; margin striate (0.5R), nonappendiculate; universal veil absent.

lamellae

free, without decurrent line on stipe apex, close(?), off-white in mass and in side view, 4.5 - 5.5 mm wide, with fimbriate margin (10× lens); lamellulae truncate to subattenuate to subtruncate.

stipe

140 × 9 mm (with stipe base inserted up to 80 mm in substrate), pallid, decorated with a pale gray pulverulence in upper 30 mm, with darker gray fibrils below shading into membranous gray narrow patches in lower half, cylindric, flaring at apex, very fragile; context pale grayish white, not changing when cut or bruised, stuffed with white cottony material that bruises ochraceous, with central cylinder 3 mm wide; exannulate; universal veil as flimsy saccate volva, submembranous and crumbling especially in upper half of limbs, measuring 30 mm from stipe base to highest point on limb, up to 17 mm wide, gray in upper half, white in lower half, collapsing.

odor/taste

Odor faintly fungoid. Taste not recorded.

macrochemical
tests

none recorded.

lamella trama

bilateral; w_cs = 50 - 55 µm (good rehydration); angle of divergence shallow or no more than 30°; subhymenial base very minimal; filamentous, undifferentiated hyphae 2.0 - 7.5 µm wide, branching, with partially inflated intercalary segments in central stratum no larger or barely larger than widest uninflated segments; terminal, inflated cells ??; vascular hyphae ?? µm wide, ??.

subhymenium

w_st-near = 10 - 20 µm (good rehydration); w_st-far = 20 - 30 µm (good rehydration); pseudoparenchymatous or comprising inflated cells with some interconnections obvious, with cells thin-walled and subglobose to broadly clavate to clavate (e.g., 12.0 × 10.0 µm), with 2 - 3 cell layers below bases of longest basidia; with basidia arising from (?)inflated cells.

basidia

4-sterigmate; clamps not observed.

partial veil

absent.

lamella edge tissue

sterile.

basidiospores

send to graphing tool

[20/1/1] (9.1-) 9.5 - 10.8 (-11.0) × (8.0-) 8.5 - 10.0 (-10.5) µm, (L = 10.1 µm; L’ = 10.1 µm; W = 9.2 µm; W’ = 9.2 µm; Q = 1.05 - 1.16 (-1.19); Q = 1.11; Q’ = 1.11), hyaline, colorless, thin-walled, smooth, inamyloid, subglobose to broadly ellipsoid, adaxially flattened; apiculus sublateral, cylindric; contents dominantly monoguttulate with or without small additional granules, occasionally granular; ?? in deposit.

ecology

North Carolina: Solitary. In dry coarse sand in mixed forest comprising chiefly Pinus strobus, Tsuga canadensis, Acer sp., and Rhododendron sp.

material examined

U.S.A.: NORTH CAROLINA—Macon Co. - Forest Service Rte. 79 (first gate on S side), Blue Valley, 10.vii.1990 Ronald H. Petersen s.n. [Tulloss 7-10-90-D] (RET 147-9, nrITS & nrLSU seq'd.).

discussion

This taxon has a virgate pileus with brown disc and gray-brown margin; the marginal striations of its pileus extend to about 1/2 of the pileus radius. It seems to have at least superficial affinity to A. submembranacea of Europe or to the subarctic A. mortenii or to the North American A. sinicoflava. However, these have the common 5' motif of rnLSU while the present taxon has the unusual motif first found by RET in A. penetratrix. Another weak volva'd species with the unusual motif is A. minnesorora

The following diagrams compare the sporographs of the four species named above:

The following figure provides a comparison of the sporographs of Amanita rhacopus and the present species:

citations

—R. E. Tulloss

editors

RET

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name	Amanita petersenii
name status	nomen provisorum
author	Tulloss & Kudzma
images	1. Amanita sp-S06, longitudinal section of stipe base and volva, Blue Valley, Macon Co., North Carolina, U.S.A.
drawing	RET - (1) sketch from field notes, Blue Valley, Macon County, North Carolina, U.S.A.

name	Amanita petersenii

name	Amanita petersenii

Spore data for collections
provisionally identified as: Amanita petersenii Tulloss & Kudzma

Spore data sets and their composite

Each spore data set is intended to comprise a set of measurements from a single specimen made by a single observer; and explanations prepared for this site talk about specimen-observer pairs associated with each data set. Combining more data into a single data set is non-optimal because it obscures observer differences (which may be valuable for instructional purposes, for example) and may obscure instances in which a single collection inadvertently contains a mixture of taxa.

basidiospore definition

Spore Measurements by Collection

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