Simonachne, a new genus for Australia segregated from Ancistrachne s.l. (Poaceae : Panicoideae : Paniceae) and a new subtribe Cleistochloinae

Abstract

A new genus, Simonachne E.J.Thomps. is described and Ancistrachne maidenii (A.A.Ham.) Vickery is transferred to it as Simonachne maidenii (A.A.Ham.) E.J.Thomps. The new subtribe Cleistochloinae E.J.Thomps. is described and is composed of four genera, Calyptochloa, Cleistochloa, Dimorphochloa and Simonachne, united by distinctive morphology that is associated with reproductive dimorphism. Phenetic analyses were used to examine the similarities of taxa and to test the consistency of results with variation in analysis inputs. Input variations included the dataset in terms of composition of the samples and morphological characters, and the cluster analysis algorithms, viz. classification, ordination and association measure. A baseline dataset was used for comparison of results and comprised 24 samples and 161 characters relating to anatomy, micro- and macromorphology of spikelets, leaves and fertile culms. Three major clusters were resolved, Cleistochloinae (‘the cleistogamy group’), Neurachninae in its original sense, and a cluster referred to as the ‘paniculate inflorescence group’ composed of Ancistrachne s.s., Entolasia and Panicum s.s. The results were congruent with a recent phylogenetic study that showed that Ancistrachne s.l., Cleistochloa s.l. and Dimorphochloa s.l. were not monophyletic. The process provided an array of morphological characters for descriptions of species and for distinguishing taxa at multiple ranks in natural groups, components of alpha and beta taxonomy respectively.