Ambispora reticulata

Abstract

A new glomeromycotean fungus,Ambispora reticulata, was found in the Swiss Alps and in the Chilean Andes. Only acauloambisporoid spores were detected so far, 87-131 x 125-150 μm in diameter and having a three-layered, yellow-brown to brown outer wall, a bi-layered, hyaline middle wall and a generally three-layered, hyaline inner wall. The middle wall has a characteristic reticulate outer surface with irregular triagonal to octagonal (usually tetrato hexagonal) pits that are surrounded by ridges. As known for all Ambispora species with acaulo-ambisporoid spore formation, the middle wall is a substantial part of the pedicel which connects the spore with the mycelium. The new species is a frequent member of arbuscular mycorrhizal fungal communities in mountainous and subalpine grasslands of the Swiss Alps at 1000-2100 m above sea level. It occurred less frequent in high alpine grasslands and at altitudes below 1000 m, where the fungus was found in a conservation tillage and a low-input tillage system. It was also detected in evergreen and in deciduous forests in the Andes of Southern Chile at elevations of 550-1600 m.