Taxonomic and nomenclatural novelties in Leucoagaricus (Agaricaceae) from Brazil
Author
Heisecke, Celeste
0000-0003-1316-2212
Programa de pós-graduação em Botânica, Escola Nacional de Botânica Tropical, JBRJ, Rua Pacheco Leão 2040, Solar da Imperatriz, 22460 - 036, Rio de Janeiro, RJ, Brazil. & Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rua Pacheco Leão 915, 22460 - 030, Rio de Janeiro, RJ, Brazil. & celeste. heisecke @ gmail. com; https: // orcid. org / 0000 - 0003 - 1316 - 2212
celeste.heisecke@gmail.com
Author
Barbosa, Jaime Andrés Duque
0000-0001-9892-9245
Programa de pós-graduação em Botânica, Escola Nacional de Botânica Tropical, JBRJ, Rua Pacheco Leão 2040, Solar da Imperatriz, 22460 - 036, Rio de Janeiro, RJ, Brazil. & Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rua Pacheco Leão 915, 22460 - 030, Rio de Janeiro, RJ, Brazil. & jimialadino @ gmail. com; https: // orcid. org / 0000 - 0001 - 9892 - 9245
jimialadino@gmail.com
Author
Neves, Maria Alice
Author
Jr, Anibal Alves De Carvalho
0000-0002-6176-2039
Programa de pós-graduação em Botânica, Escola Nacional de Botânica Tropical, JBRJ, Rua Pacheco Leão 2040, Solar da Imperatriz, 22460 - 036, Rio de Janeiro, RJ, Brazil. & Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rua Pacheco Leão 915, 22460 - 030, Rio de Janeiro, RJ, Brazil. & carvanibal @ gmail. com; https: // orcid. org / 0000 - 0002 - 6176 - 2039
carvanibal@gmail.com
text
Phytotaxa
2021
2021-03-31
494
1
42
58
http://dx.doi.org/10.11646/phytotaxa.494.1.2
journal article
10.11646/phytotaxa.494.1.2
1179-3163
5756293
Leucoagaricus nzumbae
C. Heisecke, A.A. Carvalho & M.A. Neves
sp. nov.
(
Figs 3C
,
6A–C
)
MycoBank:
―
MB 835923
Type
:―
BRAZIL
.
Rio de Janeiro
:
Teresópolis
,
Parque Nacional da Serra
dos Órgãos
, first part of the
Pedra do Sino
trail,
22°27’02.7”S
,
43°00’06.3”W
,
09 December 2016
,
Heisecke
&
Duque, C.H.C.
348
(
holotype
RB)
.
Pileus
10–13 mm
diameter, hemispherical, planeo-convex or applanate, sometimes umbonate; surface dry, smooth and brown at the center (6E8), then splitting radially and forming brownish orange fibrillose scales (6C5) on a white to yellowish-white background (1A1, 1A2); margin entire, straight, exceeding the lamellae; context less than
1 mm
broad, white, not changing when damaged. Lamellae free, ventricose,
1–3 mm
wide, white to yellowish; edge entire, concolorous with the sides. Stipe 20–30 ×
2–3 mm
, central, cylindrical, fistulose; surface fibrillose, white. Annulus superior to central, membranous, fragile, easily detachable, ascending, white. The entire basidiome turns lilac when dried (15B4, 15C4).
Basidiospores 5.2–6.9 × 3.3–4.8 µm (Q = 1.29–1.91), broadly ellipsoid to oblong, ovoid in side view, uniguttulate, yellowish in water, paler or hyaline in KOH, dextrinoid, metachromatic, thin-walled, without a germ pore. Basidia 17.5–30 × 6.6–9.3 µm, clavate, 4-spored. Cheilocystidia absent. Pleurocystidia absent. Pseudoparaphyses absent. Hymenophoral trama subregular, subhymenium cellular. Pileus covering made up of upright trichodermal elements, 19.8–67.9 × 4.7–9.8 µm, cylindrical to irregular, often tapering upwards with obtuse apex, thick-walled, with brown intracellular and parietal pigments, often encrusted, brown in water and paler in KOH. Scattered oleiferous hyphae present in the pileus context. Clamp connections absent.
Paratypes
:—
BRAZIL
.
Rio de Janeiro
:
Teresópolis
,
Parque Nacional da Serra
dos
Órgãos
, first part of the
Pedra do Sino
trail,
22°27’02.7”S
,
43°00’06.3”W
,
09 December 2016
,
Heisecke
&
Duque, C.H.C.
349
(RB, FLOR)
;
idem
,
11 December 2016
,
Heisecke
&
Duque, C.H.C.
365
(RB)
;
idem
,
19 December 2017
,
Heisecke
&
Duque, C.H.C.
498
(RB)
;
idem
,
16 March 2019
,
Heisecke
&
Duque, C.H.C.
525
(RB)
.
Etymology:—
In honor of Nzumba, a deity from the Afro-Brazilian religion Candomblé Bantu, who dresses in purple and has mud as his representative element. This name was chosen because the
type
was collected alongside an imperial trail, probably built by slaves, the muddy habitat of the species and the purplish color of the basidiomes when dry.
FIGURE 6.
Leucoagaricus nzumbae
C.H.C.349 (Holotype). A. Basidiospores. B. Basidia. C. Elements of the pileus covering. Scale bars are 10 µm. Illustration by C. Heisecke.
Distribution and habitat:—
Solitary in small groups, in the shade on moist ground among litter and clay, in tropical cloud forest in the Atlantic Forest in
Rio de Janeiro State
.
Taxonomy:—
This species can be recognized by the small basidiomes that turn completely lilac when dried, the brownish color of the pileus surface, and the trichodermal elements with intracellular and parietal brown pigments in the pileus covering.The lack of cheilocystidia is unusual for
Leucoagaricus
species.
However, after exhaustive analyses of all basidiomes collected, not a single cystidium was found, and the lamella edge is formed only by basidioles and basidia.
Due to the small size of the basidiomes (
Fig 3C
, pileus
10–13 mm
wide and stipe
20–30 mm
long),
La. nzumbae
resembles specimens of
Lepiota
, but the basidiospores are metachromatic and clamp connections are absent in the entire basidiome (
Fig 6A–C
).
Based on molecular data,
La. nzumbae
was retrieved in a strongly supported clade along with other species that also change color on drying. The clade is formed by a Mexican specimen labeled as
Leucoagaricus
cf.
coerulescens
(
Peck 1899:63
) J. F. Liang, Zhu L. Yang & Xu (2010: 1147)
, an undescribed species from
Hawaii
(ecv3754 and ecv3757), and the Asian species
Leucoagaricus viriditinctus
(
Berkeley & Broome 1871: 503
) J.F. Liang, Zhu L. Yang & J. Xu
in
Liang
et al.
(2010: 1146)
, characterized by their basidiomes that turn bluish green when dehydrated, which is quite different from
La. nzumbae
which turns lilac.
The color changes of the basidiomes in response to bruising or drying are important characteristics for the taxonomy of
Lepiota
s.l.
(
Reid 1990
,
Liang
et al.
2010
, Vellinga 2006, 2010,
Vellinga
et al.
2010
). The lilac tint of
La. nzumbae
when dry is like that found in other representatives of
Leucoagaricus
.
Leucoagaricus lilaceus
, originally reported for
Argentina
and then
Brazil
(
Sobestiansky 2005
,
De Meijer 2006
,
Rother & Silveira 2008
,
2009
,
Ferreira & Cortez 2012
), has a robust fleshy basidiome with whitish lamellae that turn pinkish with age and when dried, and the stipe base is abruptly bulbous with rhizomorphs (
Singer & Digilio 1952
,
Rother & Silveira 2009
).
Leucoagaricus variicolor
, from
Spain
, has yellowish to ochraceus-cream, volvate, fleshy basidiomes that turn pinkish when dried and has spheropedunculate cheilocystia (
Muñoz
et al.
2012
).
Lepiota roseolivida
Murrill (1912: 234)
from the
U.S.A.
also has delicate basidiomes that turn lilac when dried, but the pileus surface is livid to dull rose-lilac when fresh, which is different from the brownish color on a whitish background present in
La. nzumbae
.
Lepiota roseolivida
also has larger amygdaliform basidiospores (6.7–9.8 × 3.8–5.7 μm) and clavate cheilocystidia (
Murrill 1912
, Vellinga 2006).
Some species of
Leucoagaricus
described from
Brazil
show morphological affinities to
La.nzumbae
:
Leucoagaricus confusus
(
Rick 1937: 341
)
Singer (1951: 422)
,
Leucoagaricus imperialis
(
Spegazzini 1889: 382
)
Pegler (1997: 33)
and
Leucoagaricus tricolor
Singer (1989: 98)
. Both
La. confusus
and
La. tricolor
have small basidiomes as in
La. nzumbae
(pileus diameter <
20 mm
,) (
Rick 1937
,
Singer 1951
,
1989
). However,
La. confusus
could be differentiated by a yellowish pileus surface, absence of reaction when damaged or dried, and bigger basidiospores (10 × 5 μm) (
Rick 1937
,
Singer 1951
); and
La. tricolor
, by the reddish-brown pileus surface, lamella color that changes from grey to brownish grey on drying and the fasciculate pileus covering (
Singer 1989
). Meanwhile,
Leucoagaricus imperialis
(
Spegazzini 1889: 382
)
Pegler (1997: 33)
has a brownish pileus surface as in
La. nzumbae
, but differs from it by the bigger basidiomes (pileus
40−50 mm
diameter, stipe 100 ×
4−5 mm
) that are mostly whitish and change to brownish when dried, and the larger basidiospores (8−12 × 5.5−6.5 μm) (
Spegazzini 1889
,
Pegler 1997
).
Another
Leucoagaricus
species
reported from
Brazil
and morphologically related to
La. nzumbae
is
Leucoagaricus sulphurellus
(
Pegler 1983: 420
) B.P. Akers
in
Akers, Angels & Kimbrough (2000: 48)
, described from the Caribbean islands (
Pegler 1983
,
1997
,
Wartchow
et al.
2008
,
Rosa & Capelari 2009
). This species shares the small basidiome (pileus
8−21 mm
diameter) and the brownish pileus surface with
La. nzumbae
, but it differs by its sulphur yellow basidiome, that changes color to pinkish brown and then blue-green when damaged, basidiospores with a germ pore, and the appressed pileus covering (
Pegler 1983
,
Akers
et al
. 2000
).