Comprehensive analysis of relationships of the representatives of subfamily Cryptogrammoideae (Pteridaceae)

Abstract

This research is the first comprehensive analysis of the intrageneric relationships inside the subfamily Cryptogrammoideae: 14 taxa of Coniogrammeand one species of Cryptogramma were involved additionally in the molecular phylogenetic studies based on rbcL gene of plastid DNA; spore morphology of 32 taxa of cryptogrammoid ferns, namely 22 taxa of Coniogramme, nine species of Cryptogramma and one species of Llavea were studied using scanning electronic microscopy (SEM); 31 taxon of Cryptogrammoideae were studied using herbarium data from Herbaria across Europe and Asia (P, PE, LE, VLA, ALTB, TK) according to global botanical and geographical zones. As a result of this comprehensive analysis, we established a deep divergence of Coniogramme merillii in Coniogramme superclade: this species is the sister lineage to the remainder ofConiogramme. We revealed also the separateness of Co. suprapilosa from Co. rosthornii and Co. longissima, Co. africana from Co. lanceolata and Co. fraxinea, Co. robusta from Co. jinggangshanensis, Co. wilsonii and Co. japonica. Among Cryptogramma species, the relationship of Far Eastern Cr. gorovoi with Cr. crispa from the Caucasus and the Turkish endemic Cr. bithynica but not with any Far Eastern species was revealed. Spores of Coniogramme are characterized by simple smooth, granulate and papillate macro-ornamentation, spores of Cryptogramma species have the more coarse colliculate or tuberculate macro-ornamentation. Peculiarities of macro-ornamentation allow us to define six spore types in cryptogrammoid ferns: four spore types in Coniogramme and two spore types in Cryptogramma; the same spore type we assigned for Llavea cordifolia and Coniogramme suprapilosa. In Coniogramme, the grouping of species attending the spore type does not agree with existing classification and phylogenetic hypotheses. Genetic separateness of Co. suprapilosa corresponds with its exceptional verrucate spore sculpture not found in other Coniogramme species. In Cryptogramma, the grouping on the spore types corresponds with other morphological characteristics, existing system and molecular phylogeny. Spore ornamentation has diagnostic value in the recognition of cryptogrammoid taxa at the generic and section (in Cryptogramma) level. Sino-Japanese and Sino-Himalaian regions of Eastern Asiatic Subkingdom are the centers of origin and diversity for subfamily Cryptogrammoideae and especially for the genus Coniogramme.