Not (only) poison pies - Hebeloma (Agaricales, Hymenogastraceae) in Mexico
Author
Eberhardt, Ursula
https://orcid.org/0000-0003-1221-7074
Staatliches Museum fuer Naturkunde Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany
ursula.eberhardt@smns-bw.de
Author
Kong, Alejandro
Centro de Investigacion en Ciencias Biologicas, Universidad Autonoma de Tlaxcala, Km 10.5 carretera San Martin Texmelucan-Tlaxcala, San Felipe Ixtacuixtla, Tlaxcala, 90120, Mexico
Author
Montoya, Adriana
Centro de Investigacion en Ciencias Biologicas, Universidad Autonoma de Tlaxcala, Km 10.5 carretera San Martin Texmelucan-Tlaxcala, San Felipe Ixtacuixtla, Tlaxcala, 90120, Mexico
Author
Schuetz, Nicole
Staatliches Museum fuer Naturkunde Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany
Author
Bartlett, Peter
https://orcid.org/0000-0002-8800-3219
La Baraka, Gorse Hill Road, Virginia Water, Surrey GU 25 4 AP, United Kingdom
Author
Beker, Henry J.
https://orcid.org/0000-0001-9620-1701
Rue Pere de Deken 19, B- 1040 Bruxelles, Belgium
text
MycoKeys
2022
2022-06-30
90
163
202
http://dx.doi.org/10.3897/mycokeys.90.85267
journal article
http://dx.doi.org/10.3897/mycokeys.90.85267
1314-4049-90-163
3430D3DBCCA75AA191975F7081D21916
Hebeloma cohaerens A. Montoya & Beker, sp. nov.
Figs 8
, 9
Type
.
Mexico
.
Tlaxcala
:
Municipality of Panotla
,
1 km
al este
de San Francisco Temezontla
, approx.
19.3496°N
,
98.2784°W
, alt. approx.
2600 m
, in deciduous woodland under
Quercus
sp.,
23 Jul 2017
,
A. Montoya-Esquivel
AME3102 (
holotype
TLXM 6156; isotype BR 5020224875654V;
HJB17733
); Genbank ITS
ON202511
.
Diagnosis.
The short clavate-ventricose cheilocystidia, with average apical width less 6.5
µm
, the small (on average less than 10
x
5.5
µm
), weakly ornamented but rather strongly dextrinoid basidiospores and the whitish to cream or buff color of the pileus, differentiate this species from other
Hebeloma
species.
Etymology.
From
Hebeloma cohaerens
(adj. Latin) meaning united or joined together, to emphasize the connate habitus.
Description.
Pileus (22) 32-38 (47) mm diameter, convex, often applanate, occasionally umbonate; margin smooth, often involute, particularly when young, occasionally eroded, not hygrophanous; usually almost unicolored, usually cream or buff, sometimes slightly paler towards margin. Lamellae often adnate or adnexed, occasionally emarginate, depth up to 4 mm, white, cream to brown, with white fimbriate edge but without droplets on the lamella edge, number of full-length lamellae 70-80. Stipe (31) 37-46 (48) mm long, (5) 7-8 (10) mm diameter at median, usually cylindrical but sometimes with a clavate base, surface cream, ivory, not discoloring, fibrillose, pruinose, particularly towards apex; base with white mycelium. Context in pileus and stipe white to cream, firm, in stipe stuffed; taste not recorded, smell earthy. Spore deposit color not recorded.
Basidiospores based on n = 64 spores of the holotype, 5% to 95% percentile range 8.6-10.5
x
4.9-5.7
µm
, with median 9.4
x
5.3
µm
and av. 9.5
x
5.3
µm
with S.D. length 0.57
µm
and width 0.26
µm
; Q value 5% to 95% percentile range 1.64-1.95, with median 1.79 and av. 1.78 with S.D. 0.10; spore size based on four collections medians 9.1-9.5
x
5.3-5.6
µm
and av. 9.1-9.5
x
5.3-5.5
µm
with av. S.D. length 0.50
µm
and width 0.30
µm
, av. Q 1.65-1.78, amygdaloid, occasionally limoniform, with small apiculus and rounded apically, often subacute, with a distinct thinning of the apical wall and sometimes a papilla, usually guttulate with one or sometimes more oily drops, at most weakly ornamented (ornamentation only visible under immersion), with a perispore hardly loosening, rather strongly dextrinoid, becoming medium reddish brown in
Melzer's
reagent (O1/2; P0; D3); yellow brown in KOH. Basidia 22-27
x
5-7
µm
, with av. Q 3.7-3.8
µm
, cylindrical to clavate, hyaline, 4-spored. Cheilocystidium width near apex holotype 5% to 95% percentile range 4.7-7.7
µm
, with median 6.0
µm
and av. 6.1
µm
with S.D. 1.0
µm
; across four collections median 5.6-6.4
µm
and av. 5.5-6.3
µm
; examining approx. 20 selected cheilocystidia of each of the four collections yields a range for the avs. of 33-36
x
5.5-6.3
x
3.5-4.1
x
5.5-6.6
µm
and 33
x
6.1
x
4.1
x
6.5
µm
av. for holotype. Cheilocystidium av. ratios A/M: 1.49-1.63, A/B: 0.86-1.03, B/M: 1.59-1.88, mainly clavate-ventricose, often with one or two septa. Pleurocystidia absent. Caulocystidia similar to cheilocystidia but larger, up to 90
μm
long. Pileipellis an ixocutis with an epicutis up to 110
µm
thick, with gelatinized, hyphae up to 6
µm
wide; subcutis cream to pale yellow, and the trama below the cutis made up of cylindrical, often ellipsoid cells, up to 14
µm
wide. Clamp connections present throughout the basidiome.
Ecology and distribution.
In deciduous or mixed woodlands apparently associated with
Quercus
or
Pseudotsuga
. Growth habit mainly caespitose, sometimes with a few scattered basidiomes. To date, all collections of
Hebeloma cohaerens
recorded from Tlaxcala at altitudes of 2600 m or more.
Additional collections examined.
Mexico.
Tlaxcala
: Municipality of Panotla, 1 km al este de San Francisco Temezontla, approx.
19.3496°N
,
98.2784°W
, alt. approx. 2600 m, in deciduous woodland under
Quercus
sp., 23 Jul 2017, A. Montoya-Esquivel (TLXM AME3101, HJB17732). Municipality of Panotla, 1 km al este de San Francisco Temezontla, approx.
19.3496°N
,
98.2784°W
, alt. approx. 2600 m, in deciduous woodland under
Quercus
sp., 23 Jul 2017, A. Kong (TLXM AK17-08, HJB17737). Municipality of Terrenate, Rancho el pozo, approx.
19.5407°N
,
97.9046°W
, alt. approx. 2900 m, on soil in woodland under
Pseudotsuga
sp., 13 Jul 1995, Galindo-Flores (TLXM GF1866, HJB16779).
Remarks.
The small, short clavate-ventricose cheilocystidia, together with the small rather smooth, rather strongly dextrinoid basidiospores, support the placement of this species within
Hebeloma sect. Theobromina
. Within this section the pale cream to buff pileus color together with the caespitose habitus is unique.
The description was based on just four collections all from the same region of Mexico, and is not known from any other location. More records for this species will help to define better its morphological characters and its biogeographic preferences.
The minimum interspecific distance between the ITS sequences of
H. cohaerens
and sequences from other species is around 1.2%. The BLAST result of the type sequence of
H. cohaerens
against UNITE resulted in a hit of a soil sample sequence, pointing towards UNITE SH1563973.08FU (98.5% level). This SH includes two independently generated sequences from California (UDB0767851, soil sample,
Tedersoo et al. 2021
; DQ822802, basidiome, Point Reyes National Seashore Reserve, under
Pinus muricata
,
Peay et al. 2007
) that differ by around 0.5% from the sequences assigned to
H. cohaerens
, but match no other species. These results suggest that
H. cohaerens
may occur in the US (California) and the UNITE SH corresponding to
H. cohaerens
is likely to be SH1563973.08FU.
Figure 8.
A-B
basidiomata, holotype of
Hebeloma cohaerens
TLXM 6156 (HJB17733). Photos A. Kong.
Figure 9.
Holotype of
Hebeloma cohaerens
TLXM 6156 (HJB17733)
A
basidiospores
x
1600-
B
spore ornamentation
x
1600
C
basidiospores in
Melzer's
reagent
x
1600
D-E
cheilocystidia
x
1000
F
basidia
x
1000
G
cheilocystidia
x
500
H
caulocystidia
x
500
I
epicutis hyphae
x
1000
J
subcutis
x
1000
K
cutis
x
125. All in KOH, except
C
. Scale bars: 5
µm
(
A-F
); 10
µm
(
G-J
); 50
µm
(
K
). Photos
H.
J. Beker.