Haemodoraceae: phylogenetics, biology and conservation
Haemodoraceae are a small family of Commelinid monocots comprising ca.112 species in 16 genera. The family is commonly referred to as the bloodroot or bloodwort family due to the reddish pigmentation in the underground parts of subfamily Haemodoroideae, or as the kangaroo paw family, after the Australian genera Anigozanthos and Macropidia, whose flower shape resembles that of kangaroo paws. They are distributed mainly on southern continents and occur in Australia, New Guinea, South Africa, northern South America, Central America and the Caribbean, with one genus in North America. The family is divided into two subfamilies; the Conostylidoideae and the Haemodoroideae, the former being endemic to the Southwest Australian Floristic Region. This region is a global biodiversity hotspot and contains 80 of the 112 species of Haemodoraceae.
The family was first named by Robert Brown in 1810, who included a total of 12 Australian species then known in the genera Haemodorum, Conostylis, Anigozanthos and Phlebocarya, as well as the South African genera Dilatris, Lanaria and Wachendorfia, and the American genus Heritiera (now Lachnanthes). The neotropical genus Xiphidium was also mentioned as a possible family member.
Today, on the basis of DNA and other modern data sources, all these genera remain in Haemodoraceae, with the exception of Lanaria which is placed in Lanaricaeae near Hypoxidaceae. An additional 9 genera described since 1810 have been added to the Haemodoraceae – Tribonanthes, Blancoa, Macropidia, Barberetta, Schiekia, Pyrrorhiza, Cubanella ms and Paradilatris ms. Although Brown compared Haemodoraceae with Iridaceae, he also mentioned Philydrum in the protologue. Recent research has affirmed that Pontederiaceae are sister to Haemodoraceae and Philydraceae, Commelinaceae and Hanguanaceae are also closely related. While DNA sequence data strongly support the hypothesized monophyly of Haemodoraceae, there are no synapomorphies identified for the family.
Further molecular work has clarified evolutionary relationships within the family and a dated phylogeny has been published. Some interesting discoveries have also resulted from field study and molecular work: a field trip to Cuba to examine the endemic species Xiphidium xanthorrhizon resulted in the documentation of major differences in the floral structure between this and its sister species Xiphidium caeruleum. Molecular study also showed significant differences between the species and will lead to the naming of a new endemic Cuban genus. Molecular studies within the kangaroo paws and catspaws also showed that taxa previously thought to be part of the same species are actually only distantly related within the genus. This has important implications for conservation as the subspecies in question only occurs at a small number of locations and is therefore in need of formal scientific description to ensure accompanying conservation protection.
The research team is also addressing questions of biogeography, reproductive biology and conservation and on a larger scale, processes of speciation and extinction and their interaction with landscape processes. The project highlights the importance of southern continents in the exploration of global biodiversity and reinforces the value of detailed biological study as an effective basis for conservation.
Key publications 2006-2011
- Smith, R.J., Hopper, S.D. and Shane, M.W. (2011). Sand-binding roots in Haemodoraceae: global survey and morphology in a phylogenetic context. Plant and Soil 348: 453–470
- Hopper, S.D., Smith, R.J, Fay, M.F., Manning, J.C. and Chase, M.W. (2009). Molecular phylogenetics of Haemodoraceae in the Greater Cape and Southwest Australian Floristic Regions. Molecular Phylogenetics and Evolution 51: 19-30.
- Hopper, S.D., Chase, M.W. and Fay, M.F. (2006). A molecular phylogenetic study of generic and subgeneric relationships in the south-west Australian endemics Conostylis and Blancoa (Haemodoraceae). In J. T. Columbus, E. A. Friar, J. M. Porter, L. M. Prince, and M. G.Simpson [eds]., Monocots: comparative biology and evolution, Aliso 22: 527–538.