A new section, Lactifluus section Neotropicus (Russulaceae), and two new Lactifluus species from the Atlantic Forest, Brazil

Abstract

Lactifluus is a monophyletic genus of ectomycorrhizal fungi with about 200 described species classified in four subgenera: L. subg. Gymnocarpus, L. subg. Lactariopsis, L. subg. Lactifluus, and L. subg. Pseudogymnocarpus. Currently L. subg. Lactariopsis is considered monophyletic with approximately 57 species described and classified in four sections: Albati, Edules, Lactariopsis, and Russulopsidei. There are few species of L. subg. Lactariopsis described from the Neotropical region, however local mycologists commonly collect specimens of this subgenus during their mycological surveys. The goals of the present study are to evaluate the phylogenetic and morphological relationships of the species from L. subg. Lactariopsis found in Brazil, to contribute to the knowledge of Lactifluus in Neotropical ecosystems by describing a new section in this subgenus and two new species from Brazil, and to document L. neotropicus as a new record from Brazil. Based on morphological and phylogenetic evidence we propose Lactifluus sect. Neotropicus as a new section and Lactifluus catarinensis and L. marielleae as two new species in this section. We provide a key to the species of L. sect. Neotropicus, which is shown to be a monophyletic group of Neotropical species within L. subg. Lactariopsis. The most striking characteristic of several species in L. subg. Lactariopsis is the secondary angiocarpic development, not present in the other subgenera. Species with a secondary veil can be found in two lineages that diversified more recently than the rest of the genus: L. sect. Lactariopsis and L. sect. Neotropicus. Species that show morphological affinities with the two new species in L. sect. Neotropicus described here are commonly found and we expect a greater diversity to be revealed of this section in the Neotropical region.

Key words:

• ITS
• Lactarius
• milkcaps
• morphology
• phylogeny
• 28S

Acknowledgement

The authors thank the herbaria FLOR and RB for loaning specimens and LCME-UFSC for the SEM analysis. The MICOLAB UFSC team for the fieldwork. Dra. Melanie Roy from the University Paul Sabatier-Toulouse III, Toulouse, France, Dr Pierre-Arthur Moreau from University du Droit et de la Santé Lille 2, Lille, France, and Dra Aida Marcela Vasco Palacios from the University of Antioquia for the sequences. Dr Altielys Magnago for providing the picture of Lactifluus catarinensis (Fig. 4.3).

Disclosure statement

No potential conflict of interest was reported by the authors.

Figure 3. Microscopic structures of Lactifluus catarinensis. 1. Basidiospores. 2. Basidia. 3. Macrocystidia. 4. Basidiola. 5. Pileipellis. Scale bars in 1, 2 and 4 = 10 µm; 3 and 5 = 20 µm.

Supplemental material

Supplemental material for this article can be accessed here: https://dx.doi.org/10.1080/14772000.2020.1769221.

Associate Editor: Elliot Shubert

Additional information

Funding

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brazil (CAPES) – Finance Code 001.