New insights on the phylogeny of Tectaria (Tectariaceae), with special reference to Polydictyum as a distinct lineage

Abstract

The fern genus Tectaria (Tectariaceae) Cav. is morphologically diverse and difficult in terms of recognizing species and species groups. To infer the systematic positions of some species and identity‐unknown collections with special morphological characters, we undertook phylogenetic analyses based on sequences of five plastid regions (atpB, ndhF + ndhF‐trnL, rbcL, rps16‐matK + matK, and trnL‐F). Three analysis methods (maximum parsimony, maximum likelihood, and Bayesian inference) were used to reconstruct the phylogeny of Tectaria. The most surprising result is that T. menyanthidis (C. Presl) Copel., T. ternata (Baker) Copel., and T. variabilis Tardieu & Ching are revealed to represent a distinct lineage from Tectaria, which should be called Polydictyum C. Presl, and is supported as sister to Pteridrys C. Chr. & Ching. Other accessions of Tectaria are well resolved into four major clades, which is consistent with the results of previous studies. Of the four clades, Clade II (T. subtriphylla (Hook. & Arn.) Copel. group) is unpredictable, with morphologically very diverse species clustered there, and is supposed to be a minor evolutionary line within Tectaria in the Old World. In addition, the position of the climbing genus Arthropteris J. Sm. and the utility of molecular data in recognizing species of Tectaria are briefly discussed. As a conclusion, we formally reinstate the genus Polydictyum by providing diagnostic characters, key to species, nomenclature, and information of detailed distribution and habitat for the currently known three species.

Pteridryaceae: A new fern family of Polypodiineae (Polypodiales) including taxonomic treatments

“…With the recently reinstated genus Polydictyum (Dong et al, ), the DMP clade coined by Zhang et al () is now expanded, with maximum statistical values in all three analyses (Fig. A), to contain four genera: Draconopteris , Malaifilix , Polydictyum , and Pteridrys ; we subsequently refer to this group as the DMPP clade.…”

“…All currently recognized genera in Tectariaceae sensu PPG I () were sampled. The sampling also included species of the recently re‐established genus Polydictyum (Dong et al, ) to re‐explore the status of this putative genus. Our sampling included 21 accessions (ca.…”

“…All currently recognized genera in Tectariaceae sensu PPG I (2016) were sampled. The sampling also included species of the recently re-established genus Polydictyum (Dong et al, 2018) Holttum, 1991). In addition to Tectariaceae, the sampling included nine species of Davallia (Tsutsumi et al, 2016), five species representing four genera of Drypteridaceae, and 11 accessions representing eight species and three genera, respectively, of Lomarioptidaceae, seven accessions representing seven species of Nephrolepidaceae, seven accessions representing six species of Oleandraceae, and 17 species in 17 genera of Polypodiaceae (all families and genera defined as in PPG I, 2016).…”

“…However, Tectariaceae sensu Zhang et al () received only a weak MPJK value (65%), even based on the then largest character sampling. Most recently, Dong et al () have recovered the DMP + Polydictyum clade sister to the Triplophyllum + Hypoderris + Tectaria clade, based on five plastid markers.…”

“…(Tectariaceae), ; Polydictyum C. Presl (our Figs. 1E-1H), Dong et al, 2018). It remains unknown whether further expanded sampling of Tectaria will identify new additional major clades.…”