Polygonum schischkinii is a member of Atraphaxis (Polygonaceae, Polygoneae): evidences from morphological and molecular analyses

The Chinese endemic Polygonum schischkinii was studied from both morphological and molecular points of view. On the basis of the structure of ocreas and ocreolas, P. schischkinii appears to be a member of the genus Atraphaxis. The results of Maximum Likelihood and Bayesian analyses of combined data of the plastid [rpl32-trnL(UAG) IGS, trnL(UAA) intron, trnL-trnF IGS] and nuclear rDNA ITS1-2 regions, carried out on 61 members of tribe Polygoneae, confirmed position of P. schischkinii in the Atraphaxis clade. A new combination-Atraphaxis glareosa-based on P. glareosum, which has nomenclatural priority over P. schischkinii, is proposed. Ecological notes and a detailed distributional map of the species are also provided. © 2021 Magnolia Press. All rights reserved

A new nomenclatural change in Atraphaxis (Polygonaceae).

Yurtseva, Olga V., Govaerts, Rafaël (2022): A new nomenclatural change in Atraphaxis (Polygonaceae). Phytotaxa 552 (1): 125-126, DOI: 10.11646/phytotaxa.552.1.1

"A character does not make a genus, but the genus makes the character": three-taxon statement analysis and intuitive taxonomy

Three-taxon statement analysis (3TA) is a method that may help to formalize the taxonomical intuition of the synapomorphy of the clade as a combination of its diagnostic traits, even if each trait, if taken separately, may be found in one or many other taxa of the same relationship. Using example based on the real morphological data, we are showing that 3TA can recognize clade in case of the complete lack of it synapomorphies, as optimized under the criterion of standard parsimony

Fig. 1. A in "A character does not make a genus, but the genus makes the character ": three-taxon statement analysis and intuitive taxonomy

Fig. 1. A. Strict consensus of 61 most parsimonious phylogenetic trees; tree length = 90 steps; CI = 0.6000; RI = 0.8302, recovered from a standard cladistic analysis (MP) (Fitch Parsimony) of the complete conventionalmorphologicalmatrixofAtraphaxiss.l.(TableS1).All27unordered(non-additive)characters are parsimony informative. B. Strict consensus of two nested most parsimonious hierarchies of patterns; length = 8328 steps; CI = 0.8521; RI = 0.8264), recovered from a MP analysis of the three-taxon statement representation of the complete conventional 27 characters' morphological matrix of Atraphaxis s. l. (Table S1). The number of 3TSs (characters) is equal to 7096, all are parsimony-informative. C. Strict consensus of six most parsimonious phylogenetic trees; tree length = 56 steps; CI = 0.6071; RI = 0.8370, recovered from a MP analysis of the reduced conventional 18 characters' morphological matrix of Atraphaxis s. l. (Table S1) with the characters one, two, four, eight, 12, 16, 18, 19, and 26 excluded. D. Strict consensus of two nested, most parsimonious hierarchies of patterns; length = 5844 steps; CI = 0.8665; RI = 0.8460), recovered from a MP analysis of the three-taxon statement representation of the reduced conventional 18 characters' morphological matrix of Atraphaxis s. l. (Table S1) with characters 1, 2, 4, 8, 12, 16, 18, 19 and 26 excluded. The number of 3TSs (characters) is equal to 5064, all are parsimony-informative. All MP analyses as in PAUP* 4.0a150 (Swofford 2002) were conducted using either conventional matrices or TAXODIUM's output 3TS NEXUS files with a heuristic search of 1000 random addition replicates (saving no more than 100 trees per replicate), and the TBR branch swapping/MulTrees option into effect. Branches with a minimum length of zero were collapsed. The three-taxon statement analysis (3TA) of the unordered morphological matrix was established after it three-taxon (3TS) Williams-Siebert (WS) representation (Williams & Siebert 2000) using TAXODIUM v. 1.2 (Mavrodiev & Madorsky 2012). The 3TS permutations were performed with the following command: taxodium input_file_name. csv –ium –ob –og –nex The value of the operational outgroup was fixed as a value of Bactria lazkovii. All 3TSs were weighted uniformly and treated as ''ordered'' (Wagner Parsimony). The bootstrap resampling of both conventional and 3TS matrices have been performed as described in Mavrodiev & Madorsky (2012). The diagnostic traits are optimized using Mesquite (Maddison & Maddison 2011)

What is Atraphaxis L. (Polygonaceae, Polygoneae): cryptic taxa and resolved taxonomic complexity instead of the formal lumping and the lack of morphological synapomorphies

Background: The recently proposed recircumscription of the genus Atraphaxis (incl. Atraphaxis section Ovczinnikovia O.V. Yurtseva ex. S. Tavakkoli and Polygonum sect. Spinescentia Boissier (=A. sect. Polygonoides S. Tavakkoli, Kaz. Osaloo & Mozaff.) makes this genus fairly heterogeneous and therefore almost undefinable based on morphology. A critical comprehensive reappraisal of the group is necessary. Methods: Using the DNA sequence data (ITS1&2 regions of nrDNA and combined trnL intron + trnL–F IGS and rpl32–trnL(UAG) IGS regions of plastid genome), Maximum Likelihood (ML) and Bayesian analyses (BI) were applied for phylogenetic reconstructions of the tribe Polygoneae with special attention to Atraphaxis, and related taxa. Maximum parsimony reconstructions of the evolution of perianth morphology and sporoderm ornamentation in the tribe Polygoneae were also performed. Life history, morphology of shoots, leaf blades, ocreas, perianth and achene morphology, ultrasculpture of achene surface, and pollen morphology were compared, and SEM and LM images were provided. Principal findings: The genera Atraphaxis and Polygonum were found to be widely polyphyletic. The rarest and morphologically remarkable endemic of Tian-Shan and Pamir Atraphaxis ovczinnikovii (Atraphaxis sect. Ovczinnikovia O.V. Yurtseva ex. S. Tavakkoli) was confirmed to be a sister of the clade (Atraphaxis + Polygonum sect. Spinescentia) in plastid topology. The genus Bactria (=Atraphaxis sect. Ovczinnikovia), which circumscribes two species, is newly established as a result of this analyses. Morphological data confirm the originality of the taxon. Discussion: We are arguing for a narrow delimitation of Atraphaxis with petalloid segments and striato-perforate sporoderm ornamentation as morphological synapomorphies. The recently proposed inclusion of Polygonum sect. Spinescentia in Atraphaxis is fairly questionable from a morphological standpoint. The rank of Polygonum sect. Spinescentia requires further clarification. The generic composition of the tribe Polygoneae also requires future reappraisals