Preliminary statistical studies of the infraspecific variation in the ascospores of Nesolechia oxyspora growing on different genera of parmelioid lichens

Abstract

In order to ascertain the extent of possible host-specialization in the Nesolechia oxyspora complex, as a pilot study ascospores from 20 collections from different parmelioid hosts representing seven genera were drawn, measured, and had length:breadth ratios calculated. The data were then subjected to multiple regression analysis using Huber-White sandwich estimators of standard errors (apparently not previously used in mycology) which take account of spores not necessarily being independent variables as they might come from the same ascus, and a statistical analysis. Significant differences between collections from seven genera were found. While the sample size was too small to reach definite conclusions, it is clear that there is a finer degree of host-relatedness than hitherto expected, which may be geno- or phenotypic. A more extensive study including species from a wider range of hosts and complemented by molecular methods will be necessary to further elucidate degrees of specificity and cryptic co-speciation in the complex. A list of the 63 reported lichen hosts is included; these are distributed though 19 genera.