Agaricus macrochlamys, a New Species from the (Sub)tropical Cloud Forests of North America and the Caribbean, and Agaricus fiardii, a New Synonym of Agaricus subrufescens

Abstract

Agaricus is a genus of fungi in the family Agaricaceae, with several highly priced edible and medicinal species. Here we describe Agaricus macrochlamys, a new species, in A. sect. Arvenses, sympatric and morphologically cryptic with the edible and medicinally cultivated mushroom, A. subrufescens. Phylogenetic analyses showed that A. macrochlamys is closely related to A. subrufescens, and that A. fiardii is a new synonym of A. subrufescens. Despite being morphologically cryptic, A. macrochlamys can be distinguished from A. subrufescens by several ITS and tef1α species-specific markers and a 4-bp insertion in the tef1α sequence. Furthermore, A. subrufescens is a cosmopolitan species, while A. macrochlamys distribution is so far restricted to Mexico, the Dominican Republic, and the United States.

Keywords: Agaricaceae; Agaricus subg. flavoagaricus; Caribbean; almond mushrooms; neotropics; phylogeny; taxonomy.

Figure 1

Maximum likelihood (ML) phylogram of Agaricus sect. Arvenses based on ITS and tef1 sequence data. Bootstrap support values and Bayesian posterior probabilities greater than 50/0.9 are indicated on branches. New sequences are annotated in red and new species are in bold. T = Type specimen. * CA1110 is the strain isolation of the holotype.

Figure 1

Maximum likelihood (ML) phylogram of Agaricus sect. Arvenses based on ITS and tef1 sequence data. Bootstrap support values and Bayesian posterior probabilities greater than 50/0.9 are indicated on branches. New sequences are annotated in red and new species are in bold. T = Type specimen. * CA1110 is the strain isolation of the holotype.

Figure 2

UPGMA analysis of 66 ITS sequences of A. subrufescens and A. macrochlamys. Lowercase letters in ITS type indicate that the characteristic polymorphisms of the type are not all present.

Figure 3

Macroscopic characters of Agaricus macrochlamys from Mexico and USA. (A–K) Basidiomata. (A) Medel 1961, holotype; (B) LD201938; (C) LD201927; (D,G,H) Medel and Lorea-Hernández 2249; (E) LD201934; (F) ARB1353; (I–K) CUL-IE904. Bar = 2 cm. Photos by Lorea-Hernández (A,H); R. Medel (D,G); J. Chen (B,C,E,I–K); and A.E. Bessette (F).

Figure 4

Microscopic characters of Agaricus macrochlamys from México and USA. (A–H) In ammonical Congo red. (A,B) CUL-IE4012; (C,E,F) CUL-IE903; (D) Medel 1961, holotype; (G,H) LD201938. (A,B) Basidia; (C,D) Spores; (E,F) Cheilocystidia; (G) Hyphae of the lower surface of the annulus; (H) Pileipellis hyphae. Bar = 10 μm. Photos by J. Chen (A–C,E–H) and R. Medel (D).

Figure 5

Macroscopic characters of Agaricus macrochlamys from the Dominican Republic. (A–J) Basidiomata. (A,G) JBSD126480; (B,I) JBSD126482; (C,H) JBSD126483; (D,F) JBSD126484; (E,J) JBSD130773. Bar = 2 cm. Photos by C. Angelini.

Figure 6

Microscopic characters of Agaricus macrochlamys from the Dominican Republic. (A–J) In ammonical Congo red. (A,F) JBSD126484; (B,C) JBSD126480; (E,H–J) JBSD126482; (D,G) JBSD130773; (A,B) Basidia; (C–E) Spores; (F,G) Cheilocystidia; (H) Hyphae of the lower surface of the annulus; (I,J) Pileipellis hyphae; (J) Terminal element. Bar = 10 μm. Photos by L.A. Parra.

Figure 7

Macroscopic characters of Agaricus subrufescens. (A–I) Basidiomata. (A) LAPAM77; (B,C) LAPAM78; (D) LAPAM100; (E,F) LAPAM103; (G–I) LD201903. Bar = 2 cm. Photos by C. Angelini (A–F) and J. Chen (G–I).

Figure 8

Microscopic characters of Agaricus subrufescens from Dominican Republic. (A–H) In ammonical Congo red (LAPAM78). (A) Basidia; (B,C) Spores; (D,E) Cheilocystidia; (F) Hyphae of the lower surface of the annulus; (G,H) Pileipellis hyphae; (H) Terminal element. Bar = 10 μm. Photos by L.A. Parra.

Figure 9

Microscopic characters of type specimen of Agaricus fiardii. (A–F) In ammonical Congo red (F353, K[M] 234316, holotype). (A,B) Basidia; (C,D) Spores; (E,F) Cheilocystidia. (A–C,E,F) Bar = 10 μm; (D) Bar = 5 μm. Photos by L.A. Parra.