Plastid DNA sequences and oospore characters of some European taxa of Tolypella section Tolypella (Characeae) identify five clusters, including one new cryptic Tolypella taxon from Sardinia, but they do not coincide with current morphological descriptions

• DOI: 10.3389/fpls.2023.1096181
• Publication Date: 2023-03-01T06:48:36Z
• Authors: Anja Holzhausen; Petra Nowak; Andreas Ballot; Ralf Becker; Jasmina Gebert; Thomas Gregor; Kenneth G. Karol; Elisabeth Lambert; William Pérez; Uwe Raabe; Susanne C. Schneider; Nick Stewart; Klaus van de Weyer; Volker Wilde; Hendrik Schubert
• Keywords: oospore morphology; Tolypella; taxonomic concepts; charophytes; Plant culture; genetic diversity; Plant Science; phylogeny; SB1-1110

In Europe, the genusTolypella(Characeae) comprises four to eightTolypellataxa in sectionsRothiaandTolypellathat have been distinguished by vegetative morphology and gametangial characters such as antheridial size and oospore wall ornamentation. However, morphological differentiation is difficult in some cases due to overlapping and variable vegetative features, which in many cases are difficult to observe clearly. To clarify the taxonomic status of the five European taxa ofTolypellain sectionTolypella, sequence data of the plastid genesatpB,rbcL andpsbC forTolypella glomerata(Desv.) Leonh.,Tolypella hispanicaAllen,Tolypella nidifica(O.F. Müll.) A. Braun,Tolypella normaniana(Nordst.) Nordst. andTolypella salinaCor. were combined with data on oospore morphology, including oospore wall ornamentation. Gene sequence data identified five distinct clusters, but they were not consistent with the morphologically identified five taxa.T. glomerataconsisted of some of the samples morphologically identified asT. glomerataand seven samples ofT. normaniana, while the remainingT. glomeratasamples clustered with specimens of unclear affiliation (Tolypellasp.). We identified two clusters ofT. hispanicawithin the European material: clusterT. hispanicaI consisted of samples from various locations, whereas the second cluster (T. hispanicaII) consisted of samples ofT. hispanicafrom Sardinia Island. The remaining cluster consisted of all the specimens that had been determined asT. salinaorT. nidificain addition to two specimens ofT. normaniana. Oospore morphology was most clearly distinguishable forT. glomerata. Oospore characteristics for all other taxa were not as informative but showed some geographical and/or environmentally influenced differences, especially forT. nidificaandT. salina. Our results suggest the need to further check the different taxonomy ofTolypellasect.Tolypellain which specimens normally identified asT. glomeratamight be two different taxa,T. glomerataand an unidentified taxon;T. nidificaandT. salinaare not separate taxa;T. normanianais a diminutive variant of two differentTolypellataxa; andT. hispanicacomprises two different taxa, one from the Mediterranean island Sardinia.