Abstract
ABSTRACT The Australian endemic family Nizymeniaceae, based on Nizymenia australis Sonder, consists of three species in the two genera Nizymenia (1 sp.) and Stenocladia (2 spp.). We have reassessed the generic composition of the family based on evidence from nonfibrillar wall polysaccharides, vegetative anatomy, and the nucleotide sequences of an internal transcribed spacer, ITS 2, of the nuclear ribosomal cistron. Investigation of the polysaccharides by constituent sugar analysis, sulfate content determination, and methylation analysis, combined with gas chromatography‐mass spectrometry and infrared analysis, showed that the polysaccharides elaborated by the three species were branched, highly sulfated xylogalactans. These polysaccharides also contained significant amounts of mono‐O‐methyl galactose (5–8 mol% of total sugars), mainly 4‐O‐methyl galactose. Although no discrete chemical structures could be assigned to the polysaccharides, the analyses showed that those from Nizymenia australis and Stenocladia australis (Sonder) Silva were more alike than either was to that from S. furcata (Harvey) J. Agardh. This polysaccharide affinity was echoed by a suite of vegetative anatomical features. However, the only likely synapomorphy was the presence of refractive, thick‐walled medullary rhizines in both N. australis and S. australis. The ITS 2 sequences were inferred from direct sequencing of the products of polymerase chain reaction amplification. Comparison of the ITS 2 sequences of its three species with those of two outgroups indicated that the family Nizymeniaceae is monophyletic but that interspecific relationships within the family could not be resolved. We conclude that there is insufficient evidence to separate any of the species from the rest at the genus level. Therefore, all three species are consolidated into the genus Nizymenia. This necessitates nomenclatural changes of Stenocladia australis to Nizymenia conferta (Harvey) Chiovitti, Saunders, et Kraft comb. nov.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
