A New Name and Genus For Pingao
Pingao, one of the key sand binders of the New Zealand sandy beaches and dune systems, has long been known in New Zealand as the sole representative of the endemic genus Desmoschoenus. Desmoschoenus was proposed by Joseph Hooker in 1853 to accommodate the species which had previously been known as Isolepis spiralis.
Since then Desmoschoenus has been in almost constant use despite lacking universal support for the genus. In 1878 Johann Boeckeler legitimised a Banks and Solander manuscript name Scirpus frondosus, and in 1916 George Druce proposed Scirpus spiralis for pingao. In 1996 two South African botanists published a paper in the New Zealand Journal of Botany: Browning & Gordon-Gray (1996) noticed that the ovules of pingao were held within a gynophore, a small cup-like structure. Gynophores are the defining character of a largely South African genus, Ficinia. They also noted that pingao was not really that different from other South African species of Ficinia. New Zealanders seem to have ignored what this paper was driving at, and Desmoschoenus remained intact.
Results, published last in March 2010 in the New Zealand Journal of Botany 48 show why Desmoschoenus is better treated as Ficinia, and the authors provide the necessary combination in that genus for the species – F. spiralis (A.Rich.) Muasya et de Lange. The authors use data pooled from two molecular markers, and a sampling of 18 Ficinia, 20 Isolepis, one Hellmuthia and one Scirpoides. The paper also illustrates the diversity of Ficinia, and included are those species to which Desmoschoenus is closely allied. They argue that, aside from the all important gynophore, the presence of a condensed and spirally arranged paniculate inflorescence is another key feature shared by the two genera.
The unusual position of Ficinia spiralis as the sole endemic of the genus to be found outside South Africa, may seem remarkable. However in the New Zealand Flora there is one other parallel, Bulbinella, which is a genus shared by both countries but not found in between (although Bulbinopsis comes pretty close to it).
Read the full story here:
By Peter de Lange
DOC, Plant Conservation Research Scientist
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Posted: 19/04/2010