Agaricus sect. Pantropicales L.A. Parra, Angelini, B. Ortiz, Linda J. Chen & Callac, 2018

Parra, Luis A., Angelini, Claudio, Ortiz-Santana, Beatriz, Mata, Gerardo, Billette, Christophe, Rojo, Carlos, Chen, Jie & Callac, Philippe, 2018, The genus Agaricus in the Caribbean. Nine new taxa mostly based on collections from the Dominican Republic, Phytotaxa 345 (3), pp. 219-271 : 236

Agaricus sect. Pantropicales L.A. Parra, Angelini, B. Ortiz, Linda J. Chen & Callac , sect. nov.

MycoBank: MB823276.

Type: Agaricus lodgeae L.A. Parra, Angelini & B. Ortiz.

Etymology: because of its distribution in tropical America (Caribbean region) and tropical Asia ( China and Thailand). From the Greek “ pan ” meaning all, and the Latin nominative plural adjective tropicales meaning of the tropics (from the Latin tropicus, which, in turn, derives from the Greek tropikos). Thus, the epithet means: Agaricus of the tropics.

Original description, Morphological description: Schäffer’s reaction positive dark reddish purple or reddish brown, and KOH reaction yellow when observable on the pileus surface of dried collections. Odor of anise or of almonds when rubbed or cut. Annulus superous, thin, one-layered (simple), without scales in its lower surface. Cheilocystidia generally simple or with one or two septa at the base, usually clavate, pyriform or more or less globose. Spores lacking a rudimentary apical pore, except in some spores of LAPAM 45.

Note: A. candidolutescens Linda J. Chen & R.L. Zhao ( Zhao et al. 2016: 258) was described as having a negative Schäffer’s reaction when fresh. However, reexamination of the dry holotype specimen showed that it had a reddish brown positive Schäffer’s reaction.

Section-specific ITS markers: [e-mail] marker characterizes the members of A. sect. Pantropicales among all the available sequences of A. subg. Minores . However, the characteristic nucleotide C is also present at homologous positions in samples of A. subg. Minoriopsis. Using the two flanking nucleotides [cagcTCAtgct@135– 137], we found that the short DNA segment [TCA] characterizes all samples of A. sect. Pantropicales exclusively and is not found in other sections in either A. subg. Minores or A. subg. Minoriopsis.

Stem age and phylogenetic support: In the maximum clade credibility (MCC) tree of Chen et al. (2017) the well-supported (PP ≥ 0.99) A. sect. Pantropicales, which was provisionally named A. sect. 1, is sister to A. sect. Leucocarpi and consequently has the same stem age of 27.64 Ma. In our ITS tree ( Fig. 1 ), it is also well supported (ML bootstrap support 84%; PP = 1) and includes four species or putative species.

Figures

FIGURE 1. Maximum likelihood phylogram of Agaricus subg. Minores, A. subg. Minoriopsis, and A. subg. Flavoagaricus resulting from analysis of ITS sequence data. The best scoring RAxML ITS tree is rooted with A. campestris. The bootstrap support values greater than 50% are indicated, and branches with Bayesian posterior probabilities greater than 0.8 are in bold. Species sampled from the Dominican Republic are in red; new taxa are in bold. T = Type specimen.