About Drosera erythrorhiza subsp. magna N.Marchant & Lowrie
This entry covers Drosera erythrorhiza subsp. magna, described in 1992 by N. G. Marchant and Allen Lowrie. Drosera erythrorhiza, commonly known as the red ink sundew, is a perennial tuberous carnivorous plant in the genus Drosera that is endemic to Western Australia. It grows in a rosette form, and is distinguished from other species in section Erythrorhiza by its many-flowered cymose inflorescences that can hold up to 50 individual flowers. D. erythrorhiza was first formally described by John Lindley in his 1839 publication A sketch of the vegetation of the Swan River Colony. In 1992, Marchant and Lowrie described three new subspecies of D. erythrorhiza, which also established the autonym D. erythrorhiza subsp. erythrorhiza. The subspecies were split from this variable species primarily based on differences in leaf morphology and distribution. D. erythrorhiza subsp. collina is named for its native hilly habitat, and typically produces more leaves of varying shapes within a single rosette. Compared to the other two subspecies, D. erythrorhiza subsp. erythrorhiza has fewer, wider leaves. D. erythrorhiza subsp. magna, the subspecies covered here, has larger, wider leaves than D. erythrorhiza subsp. erythrorhiza, and frequently produces more leaves. The fourth recognized taxon, D. erythrorhiza subsp. squamosa, was originally described at the species rank as Drosera squamosa by George Bentham in 1864. Marchant and Lowrie later reclassified it as a subspecies of D. erythrorhiza. Subspecies squamosa differs from subsp. erythrorhiza by its red leaf margins, which form from its dense red tentacles. Earlier, in his 1906 taxonomic monograph of the Droseraceae, Ludwig Diels published a new variety: D. erythrorhiza var. imbecilla. In 1999, Jindřich Chrtek and Zdeňka Slavíková proposed an alternative taxonomy, arguing that all tuberous Drosera (the entire Drosera subgenus Ergaleium) should be moved into Johann Georg Christian Lehmann's 1844 genus Sondera, which had previously been reduced to a synonym of Drosera. In this reclassification, Chrtek and Slavíková elevated Marchant and Lowrie's subspecies to full species rank: Sondera collina, S. erythrorhiza, S. magna, and S. squamosa. This alternative reclassification is not widely accepted by the botanical community.
