AUTHOR=Holzhausen Anja , Nowak Petra , Ballot Andreas , Becker Ralf , Gebert Jasmina , Gregor Thomas , Karol Kenneth G. , Lambert Elisabeth , Pérez William , Raabe Uwe , Schneider Susanne C. , Stewart Nick , van de Weyer Klaus , Wilde Volker , Schubert Hendrik 

TITLE=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

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1096181

DOI=10.3389/fpls.2023.1096181

ISSN=1664-462X

ABSTRACT=<p>In Europe, the genus <italic>Tolypella</italic> (Characeae) comprises four to eight <italic>Tolypella</italic> taxa in sections <italic>Rothia</italic> and <italic>Tolypella</italic> that 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 of <italic>Tolypella</italic> in section <italic>Tolypella</italic>, sequence data of the plastid genes <italic>atp</italic>B, <italic>rbc</italic>L and <italic>psb</italic>C for <italic>Tolypella glomerata</italic> (Desv.) Leonh., <italic>Tolypella hispanica</italic> Allen, <italic>Tolypella nidifica</italic> (O.F. Müll.) A. Braun, <italic>Tolypella normaniana</italic> (Nordst.) Nordst. and <italic>Tolypella salina</italic> Cor. 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. <italic>T. glomerata</italic> consisted of some of the samples morphologically identified as <italic>T. glomerata</italic> and seven samples of <italic>T. normaniana</italic>, while the remaining <italic>T. glomerata</italic> samples clustered with specimens of unclear affiliation (<italic>Tolypella</italic> sp.). We identified two clusters of <italic>T. hispanica</italic> within the European material: cluster <italic>T. hispanica</italic> I consisted of samples from various locations, whereas the second cluster (<italic>T. hispanica</italic> II) consisted of samples of <italic>T. hispanica</italic> from Sardinia Island. The remaining cluster consisted of all the specimens that had been determined as <italic>T. salina</italic> or <italic>T. nidifica</italic> in addition to two specimens of <italic>T. normaniana</italic>. Oospore morphology was most clearly distinguishable for <italic>T. glomerata</italic>. Oospore characteristics for all other taxa were not as informative but showed some geographical and/or environmentally influenced differences, especially for <italic>T. nidifica</italic> and <italic>T. salina</italic>. Our results suggest the need to further check the different taxonomy of <italic>Tolypella</italic> sect. <italic>Tolypella</italic> in which specimens normally identified as <italic>T. glomerata</italic> might be two different taxa, <italic>T. glomerata</italic> and an unidentified taxon; <italic>T. nidifica</italic> and <italic>T. salina</italic> are not separate taxa; <italic>T. normaniana</italic> is a diminutive variant of two different <italic>Tolypella</italic> taxa; and <italic>T. hispanica</italic> comprises two different taxa, one from the Mediterranean island Sardinia.</p>