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RMR Boll. AMER 94, Anno XXXI, 2015 (1): 29-33
PAOLO PICCIOLA, ELISEO BATTISTIN
OUDEMANSIELLA STEFFENII: AN INTERESTING TAXON FROM BRAZIL
Abstract
The macro- and microscopical features of a Brazilian collection of are
reported. Photographs of basidiomes, some microscopic structures and a black and white plate are
provided. The authors make several taxonomic considerations and illustrate its distribution over Central
and South America. A comparison with allied entities belonging to the same section Dactylosporina, i.e.
O. cephalocystidiata, O. glutinosa, O. macracantha and other sections conclude the work.
Riassunto
, nonché presentati alcuni fotocolor dei basidiomi, di alcuni elementi microscopici
distribuzione della specie nell’America centrale e meridionale. Comparazioni con taxa simili apparteneti
alla medesima sezione Dactylosporina, quali O. cephalocystidiata, O. glutinosa, O. macracantha e
altre sezioni concludono il lavoro.
Key words: Neotropics, taxonomy.
Introduction
During a recent journey in Brazil one of the authors (P.P.) picked up an interesting species
belonging to the genus Oudemansiella. Hereby we report on it in order to spread the knowledge
of such an entity and similar ones to people and mycologists who are not familiar with them.
Materials and Methods
camera. The description of macroscopic features derived from the observation of fresh specimens,
while the microscopic analysis was made on fragments of dried material previously hydrated by
distilled water and stained by Congo red or Floxine. We calculated the gracility index (IG) of our
specimen according to (1983). IG = St2 × (D×d)-1 where IG = index of gracility, St = stipe
length, D = diameter of pileus, d = diameter of stipe. Technical terms used for the morphological
description refer to (1998). Authors of fungal names were quoted in accordance
with the indications of www.indexfungorum.org/Names/AuthorsOfFungalNames.asp and
www.mycobank.org. The exsiccata were deposited in the authors’ herbaria.
TAXONOMY
Oudemansiella steenii (Rick) Singer, Lilloa 26: 66 (1954)
Basionym: Rick, Brotéria Série Botânica 24: 99 (1930).
Homotypic synonyms:
(Rick) Dörfelt, Feddes Repertorium Specierum Novarum Regni Vegetabilis
96: 237 (1985);
(Rick) Boekhout & Bas, Persoonia 13 (1): 55 (1986).
Pileus
translucently striate. Surface rugose at centre, smooth elsewhere, almost viscid, soon dry,
yellow-brown at centre, whitish or greyish at margin.
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Microscopic table. A. Basidioles; B. Pleurocystidia; C. Spores; D. Basidia; E. Caulocystidia;
F. Pileipellis; G. Hymenophoral trama. Drawing by Paolo Picciola
Lamellae adnexed to emarginate, moderately distant, ventricose, up to 6 mm broad, white,
Stipe 150 ×
Context white. Odour none, taste mild.
Spore print not recorded.
Spores (9)11-14(15) × (7)9-10(13) µm (without spines); Q = 1.0-1.2, mainly globose, but also sub-
globose, hyaline, inamyloid, thin walled, echinate. Spines 2.0-3.5 µm long having a rounded apex.
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Basidia 36-60 × 12-19(22) µm, clavate, hyaline, 2 and 4-spored.
Cheilocystidia not observed.
Pleurocystidia 90-120 × 25-27 µm, fusiform to lageniform with obtuse to subcapitate apex,
Caulocystidia 55-90 ×
Hymenophoral trama (sub)regular, made up of septate and hyaline cylindrical hyphae
2-20 µm wide and up to 120 µm long. There are sporadic clamp-connections.
Pileipellis a hymeniderm of clavate, pyriform, spheropedunculate cells 18-60 × 14-23 µm,
thin-walled which originate from a layer of hyphae 4-8 µm wide.
Stipitipellis a cutis of parallel, cylindrical hyphae 7-19 µm wide. Clamp-connections not
observed.
Clamp-connections
Ecology in a forest of Araucaria angustifolia (Bertol.) e (980 m elevation), on the ground
among buried woody debris.
Phenology 9 Jan 2014.
Material examined Brazil, Paraná, Curitiba, Campina Grande do Sul, leg. et det. P. Picciola.
Discussion
With regard to the taxonomy of xeruloid/oudemansielloid taxa (2010)
recognised eight genera based on morphological and molecular data, viz. Dactylosporina (Clémençon)
Dörfelt, Hymenopellis R.H. Petersen, Mucidula Pat., Oudemansiella Speg., Paraxerula R.H. Petersen,
Ponticulomyces R.H. Petersen, Protoxerula R.H. Petersen e Xerula Maire, while . (2009) took
into account only three genera, i.e. Xerula s. str., Oudemansiella
In her review of the Petersen & Hughes’ monograph, (2010) stated that “recognition
of non-monophyletic genera is very problematic” and “the solution might be to recognize three genera”:
Xerula ss. str., Oudemansiella and Paraxerula, sharing substantially the Chinese authors’ point
of view. Within the genus Oudemansiella . (2009) placed the species with echinulate
spores, like (Rick) Singer, into the section Dactylosporina which (1979)
instead had considered as a subgenus. Nowadays the aforementioned section encompasses
four entities: O. cephalocystidiata (R.H. Petersen & Aime) Wartchow described from Guyana,
O. glutinosa Singer found in Colombia, Ecuador and Guyana, O. macracantha Singer reported
from Argentina, Bolivia Brazil, Colombia, Mexico, Panama and Venezuela and picked
up in Argentina, Bolivia, Brazil, Costa Rica and French Guyana.
O. macracantha is the closest species and according to in
× 13.5-13.8 µm vs 10-14 × 9-13 µm) and longer spines
(3.5-5.5 µm vs 1.4-3.5 µm) of the spores. A particularly interesting feature is the gracility index
(IG), a biometric index introduced by (1093) while studying the genus Micropsalliota
Höhn, whose meaning was explained in the section Materials and Methods of this paper.
(2014) by comparing slender basidiomes of both taxa ( and
O. macracantha) noted that the IG of O. macracantha (350) was much greater than the one of
(140). The IG of our specimen is 64, closer to the typical values of
The slenderness of the basidiomes of and O. macracantha is widely accepted for species
segregation ( 1964; , 2010; 2010). Controversial is
instead the case of the number of spines of the spores. In the protologue of O. macracantha
.
Later (1964) also included the number of spines and slenderness of stipe as important
features useful for separating such close species reporting the presence of 38-42 spines per
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Figure 1. Photo by Paolo Picciola
Figure 2Hymenial cystidia and one spore. Photo by Eliseo Battistin
basidiospore; almost identical data are presented by (2010) who described
basidiospores of having more than 30 spines.
On the contrary O. macracantha were more
numerous and longer than those of Regarding this issue it is worth reporting that
think that the images provided by (2008) probably correspond to
due to the relatively shorter basidiospores spines depicted compared to the type
specimen. In our opinion a detailed statistical survey on the number of spines per basidiospore
photographed by SEM should be done in order to solve the above mentioned question,
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also because counting spines by the light microscope is not very easy and can be imprecise.
As far as we are concerned we measured many spines and found that their size ranges from
2 to 3,5 µm, values which match those of . (2008) also reported an additional
feature that perhaps could help segregate the echinulate spored Oudemansiella: in O. macracantha
the spines remain turgid in spite of the vacuum applied by electron microscope, while in
they are partially collapsed after SEM preparation.
Regarding the caulocystidia (1964) reported on the existence of specimens with
pure white or white and umber stipes, so hyaline or fuscous caulocystidia can be observed.
O. cephalocystidiata is distinguished from especially on account of the presence of
capitate caulocystidia and smaller spores provided with a lesser number of spines.
In comparison with possesses smaller basidiospores, gelatinized zones
in the pileus and stipe and cylindrical to vermiform caulocystidia. Other temperate or tropical
Oudemansiella, like O. canarii (Jungh.) Höhn., O. radicata (Relhan) Singer and O. subnigra Singer
are impossible especially because
all of them have smooth spores.
Acknowledgements
We are very grateful to Dr. Lucio Martin Zavala Gallo (Buenos Aires, Argentina) for providing
us with useful references.
Authors’ addresses
Via D’Alviano 86, 34144 Trieste (TS).
E-mail: paolo.picciola@libero.it
Museo di Storia Naturale, Corso Italia 63, 36078 Valdagno (VI).
E–mail: t
References
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