New Names For New Zealand Filmy Ferns
Ebihara et al. (2006) have just published a worldwide revision of the Hymenophyllaceae (Filmy Ferns) based mainly on both molecular sequences obtained from the chloroplast gene rbcL, (including the following regions rbcL-accD and rps4-trnS) and morphology. From their work they conclude that subdivision of Trichomanes is necessary to maintain monophyly. A major departure from past treatments is the recognition that kidney fern (known here as either Trichomanes reniforme G.Forst or Cardiomanes reniforme (G.Forst.) C.Presl) is better placed within Hymenophyllum Sm., and as the species epithet “reniforme” is preoccupied within that genus a new name Hymenophyllum nephrophyllum Ebihara et K.Iwats. is proposed.In addition, Trichomanes venosum R.Br. is reinstated as the type of the revived genus Polyphlebium Copel., and both the endemic T. colensoi Hook.f., and indigenous T. endlicherianum C.Presl. are transferred to that genus as P. colensoi (Hook.f.) Ebihara et K.Iwats and P. endlicherianum (C.Presl.) Ebihara et K.Iwats, respectively.
The remaining two species of Trichomanes, T. elongatum A.Cunn. and T. strictum Menzies ex Hook. et Grev. have been moved to the genus Abrodictyum C.Presl. as A. elongatum (A.Cunn.) Ebihara et K.Iwats. and A. strictum (Menzies ex Hook. et Grev.) Ebihara et K.Iwats. respectively.
Only one Hymenophyllum present in New Zealand, H. ferrugineum Colla is affected by their treatment. The name H. frankliniae Colenso is now revived for the New Zealand plants previously known as H. ferrugineum. H. frankliniae is regarded as endemic to New Zealand.
While the research offers an improvement on past attempts to split the family, further work is needed to justify some of these changes, particularly why Trichomanes has been split into segregate genera when the molecular sequence data shows much the same levels of divergence in Hymenophyllum.
References
Brownsey, P.J.; Dods-worth, J.C. 2000: New Zealand ferns and allied plants. David Bateman Ltd., Auckland.
Ebihara, A.; Dubuisson, J-Y.; Iwatsuki, K.; Hennequin, S.; Ito, M. 2006 : A taxonomic revision of Hymenophyllaceae. Blumea 51: 221-280.
Posted: 18/08/2006