Three New Species of Lichinella Described from Mexico

Abstract

The new species Lichinella intermedia, L. flexa and L. robustoides are described for thefirst time. L. intermedia differs from other species of the genus by, in part, foliose lobes bearing elongate thallinocarps, and thus resembles certain species of the genus Gonohymenia. L. flexa and L. robustoides are only known in sterile condition. L. flexa is characterized byfanshaped lobes and a compact axial strand. In L. robustoides the lobes are diversely branched and include a central strand of loosely interwoven hyphae with interspersed algal cells. In L. flexa and L. robustoides most of the thalli bear galls caused by a lichenicolous pyrenomycete which might be misinterpreted as fruiting structures of the lichen. In L. flexa the galls have a lateral position, in L. robustoides they occur predominantly at the tip of the lobes. New localities are given for Lichinella americana Henssen, L. robusta Henssen and L. stipatula Nyl. including first records for some countries. The genus Lichinella Nyl. is characterized by a fountain-like arrangement of the thallus hyphae and the presence of thallinocarps, a unique type of apothecium in the lichen family Lichinaceae in which asci are developed between the vegetative hyphae of the thallus giving rise to a gall-like fruiting body (Henssen 1963, 1968). Gonohymenia Steiner, the second genus of the family with a corresponding developmental morphology (Henssen 1963, 1979; Henssen et al. 1981), differs in the anatomy of the thallus and in foliose lobes in most of the species. The discovery of an undescribed Lichinella species with, in part, foliose lobes which might cause difficulties in the separation of the two genera has been mentioned previously (Henssen 1979). The new species is described in the present paper as L. intermedia. It has been collected by one of us (T. H. Nash) in the Sonoran Desert of Mexico together with two other undescribed Lichinella species resembling in habit L. robusta Henssen, a species known from the Old World. The isolation and characterization of the phycobiont of L. intermedia is the work of B. Biidel; A. Henssen is responsible for the taxonomic treatment in the present paper. METHODS The studies of the internal morphology of thallus and ascocarps were performed by the standard method of embedding freezing microtome sections in lactophenol cotton-blue (LPCB). The amyloid reaction of the hymenium was studied by adding Lugol's solution directly to sections mounted in water without pretreatment with KOH. For SEM-studies air dried or critical point dried specimens were sputter-coated with gold and viewed with a Leitz AMR 1200 B. The cultivation of the phycobiont followed the methods published by Biidel and Henssen in 1983. The terminology follows Henssen et al. (1981).