Melanogaster minysporus sp. nov., a new sequestrate member of the Boletales from Mexico

Melanogaster minysporus sp. nov. un nuevo miembro secuestrado de los Boletales de México

Efrén Cázares¹, Gonzalo Guevara², Jesús García², James M. Trappe¹

¹ Oregon State University, Department of Forest Ecosystem and Society, Corvallis, Oregon 97331–5752, USA.

² Instituto Tecnológico de Cd. Victoria, Av. Portes Gil 1301 Pte. C.P. 87010, A.P. 175 Cd. Victoria, Tam., México.

*Autor para correspondencia:
mycoroots@comcast.net

Received 10 October 2008
Accepted 5 December 2008

Resumen

Se describe una nueva especie Melanogaster minysporus recolectada en el norte de México, en el estado de Nuevo León. La especie se distingue por presentar un peridio amarillo brillante que se mancha de rojizo cuando se maltrata y por las esporas pequeñas.

Palabras clave: Paxillaceae, hipogeos, Quercus.

Abstract

Melanogaster minysporus is described as a new species from northern Mexico (Nuevo Leon). It is distinctive in the genus in having a bright yellow peridium that stains reddish where bruised in fresh and small spores.

Key words. Paxillaceae, hypogeous, Quercus.

Introduction

Carl Lumholtz, a Norwegian explorer, collected Melanogaster variegatus var. mexicanus Farlow nom. nud. (= M. umbrinigleba Trappe & Guzmán) while exploring the Chihuahuan mountains in northern Mexico (Lumholtz, 1902). This was the first record of a sequestrate fungus from Mexico. Cázares et al. 1992 described Melanogaster variegatus found in oak forests in northern Mexico. Here we describe another new Melanogaster species from northern Mexico. It is notable for its bright yellow peridium and small spores.

Materials and methods

The methods of Castellano et al. (1989) were used for the morphological description. Hand–cut sections were mounted in 5% KOH and Melzer's reagent for examination by compound– and stereomicroscopy.

Results

Melanogaster minysporus Cázares, Guevara, García & Trappe, sp. nov.

Figures 1–3

Basidiomata 13–35 x 10–27 mm, globosa vel subglobosalobata. Peridium flavissimum, ubi contusum rubescens, 160–240 µm crassum, hyphis intertextis. Gleba solida, gelatinosa–catilaginea, maturitate brunneola vel brunnea venis albis vel flavis marmorata. Sporae subfusiformes vel obovoideae, (5–) 5.5–6.5 x (3–) 4–5 µm, laeves, avellaneaevelbrunnea.

Holotypus hic designatus: Mexico, Nuevo Leon, Santiago, El Barro, Guevara 907, ITCV

Basidiomata hypogeous, 13–35 x 10–27 mm, globose to subglobose–lobed, depressed at the base, the surface smooth to finely fibrillose, bright yellow, staining reddish where bruised when fresh. Gleba solid, gelatinous–rubbery, pale brown in youth, at maturity dark brown with white to yellow, sterile veins. KOH reddish brown on fresh peridium and black on dried specimens. FeS0₄ black on dried specimens.

Peridium 160–240 µm thick. Epicutis of appressed, hyaline, thick–walled up to 1 µm thick, interwoven hyphae upto 4 µm in diam with clamp connections, orange–brown to yellow–brown in KOH and Melzer's reagent. Subcutis of interwoven hyphae, thin– to thick walled, hyphae hyaline in KOH and yellowish in Melzer's reagent. Spores (5–) 5.5–6.5 x (3–) 4–5 µm, subfusoid to obovate, smooth, thick–walled, up to 1 µm thick, the sterigmal attachment distinct, in KOH and Melzer's reagent yellow brown to brown singly, dark brown to black in mass.

Etymology: Greek, miny– (small) and spora (spores).

Habitat and season: Hypogeous to subhypogeous, single to gregarious, in mixed Pinus–Quercus forests, under Quercus canbyi and Q. rhyzophylla. August through September.

Discussion. This species is distinguished by its bright yellow peridium that stains reddish where bruised when fresh, KOH and FeSO₄ black on dried peridium, and small spores. Melanogaster ovoidisporus Y. Wang, described from China (Wang et al., 1995) is a similar species with small spores (5–) 5.5–6.5 (–7) x (3.5–) 4–5 (–5.8) µm, but its peridium is brown. They also described M. ovoidisporus var. angustatosporus K. Tao, Chang & Liu with narrower spores 5.5–6.5 (–7) x 3–4 µm.

Alpova microspora (Velen.) Trappe, has a yellow peridium and a rubbery–gelatinous gleba, but its spores are fusiform to oblong, (4–) 4.5–6 (–7) x 2–3 (–4) µm and its gleba stains red when exposed; this species was described from central Europe (Trappe, 1975).

Acknowledgments

We thank the Dirección General de Educación Superior Tecnológica for financial support.

References

Castellano, M.A., J.M. Trappe, Z. Maser, C. Maser, 1989. Key to spores of the genera of hypogeous fungi of north temperate forests with special reference to animal mycophagy. Mad River Press, Eureka, California.         [ Links ]

Cázares, E., J. García, J. Castillo, J. M. Trappe, 1992. Hypogeous fungi from northern Mexico. Mycologia 84: 341–359.         [ Links ]

Lumholtz, C. 1902. Unknown Mexico. Vol 1. Charles Scribner's Sons, New York.         [ Links ]

Trappe, J. M. 1975. A revision of the genus Alpova with notes on Rhizopogon and the Melanogastraceae. Nova Hedwigia Beiheft 51: 279–310.         [ Links ]

Wang, Y., Chang, M., Tao, K., Liu, B. 1995. New species and new varieties of the genus Melanogaster from Ching. Journal of Shanxi University (Nat. Sci. Ed.) 18: 449–453.        [ Links ] ]]> 1989 1992 84 341-359 1902 1 1975 51 279-310 1995 18 449-453