NOVON 9(1): 77-78. 1999.
Robert R. Mill
Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh EH3 5LR, Scotland, United Kingdom
Abstract. The new combination Nageia nankoensis (Hayata) R. R. Mill is proposed, and the affinities of the species with N. formosensis and N. nagi are discussed briefly. Nageia nankoensis is endemic to northern Taiwan, N. formosensis only to the south tip of the island; the latter is not native in northern Taiwan as mis-stated by some authors. It is shown that this error may have arisen because of a wrong citation of the type of N. formosensis by Li, which has been followed in later literature.
The revision of the gymnosperms for the Flora of China is in progress. Following the views of many authors, Nageia Gaertner (Podocarpaceae) is here regarded as a genus separate from Podocarpus LíHéritier ex Persoon. Indeed, Nageia was recently raised to family rank, as Nageiaceae, by Fu (1992). This ranking is not accepted here, pending further work in progress on Podocarpaceae sensu lato at the Royal Botanic Garden Edinburgh. However, Fuís generic limits of Nageia agree with those adopted by me for the Flora of China treatment. De Laubenfels (1969, 1987) took a much broader view of the genus and included various species from Africa, South America, and the Australasia-Pacific region, which Page (1989) segregated as the genera Afrocarpus C. N. Page and Retrophyllum C. N. Page.
In the Flora of China, it is proposed to recognize the taxon Podocarpus nankoensis Hayata at species rank within Nageia. Most other necessary combinations in Nageia have been made by de Laubenfels (1987) and Page (1989). However, Podocarpus nankoensis was regarded as a synonym of N. nagi (including N. formosensis) by de Laubenfels, and of N. formosensis by Page.
Nageia nankoensis (Hayata) R. R. Mill, comb. nov. Basionym: Podocarpus nankoensis Hayata, Icon. Pl. Formos. 7: 39. 1918. TYPE: [Taiwan]. "Hab. Nanko, leg. B. Hayata Mai 1916" (holotype, TI not seen).
Nageia nankoensis and N. formosensis (Dummer) C. N. Page are both endemic to Taiwan. The latter was based on Podocarpus formosensis Dummer, the type of which (Henry 1357, K) was collected by Schmüser at the extreme south tip of the island. Unfortunately, Li and Keng (1954: 43) and Li (1963: 40) have wrongly stated that the type of N. formosensis is Henry 1446, which was collected at Tamsui (Tanshui) at the north end of the island. This has led to considerable confusion between N. formosensis and N. nankoensis in some later literature, including the sinking of the latter as a synonym of the former by Page (1989) and the citation of N. formosensis as occurring in northern Taiwan by Li (1963). The two plants are in fact separable by leaf and branch characters and are here recognized as separate species, as was done under Podocarpus by Hu (1964: 33, 35). This has necessitated a new combination in Nageia for Podocarpus nankoensis. Huís distribution information for both species is correct.
Nageia formosensis is distinguishable from N. nankoensis and N. nagi (Thunberg) Kuntze, by its leaf morphology: many leaves are obovate or obovate-elliptic rather than lanceolate or ovate-elliptic, and those that are obovate have very broad, truncate tips, which are frequently blackened (Dummer likened this character to them having been touched by a hot iron). Obovate leaves have not been seen in any specimens of N. nagi or N. nankoensis, although leaf shape in both is variable, particularly in length : width ratio. (This has led to the recognition of varieties within N. nagi as represented in Japan). Nageia formosensis, which only occurs in southern Taiwan, has been recently reduced to varietal rank, as N. nagi var. formosensis (Dummer) J. Silba (Silba, 1990: 38), but this seems too low a rank; if a broad concept of N. nagi is preferred, N. formosensis should be recognized as a subspecies of it.
Nageia nankoensis is more similar to N. nagi than it is to N. formosensis but tends to have narrower, more distinctly lanceolate leaves. It is endemic to northern Taiwan. Specimens from Hainan that have been identified as N. nankoensis (e.g., McClure 8131 (E, K) from Nodoa; C. I. Lei 745 (K) from Ku Tung Village; W. T. Tsang 17430 (E, K) from Paak Shek Shan) all have broader, much more broadly obtuse leaves than any plants of N. nankoensis from Taiwan. They have been compared with specimens of N. nagi from Japan and China and showed no significant differences. Therefore, these Hainan plants are here considered to belong to N. nagi. This accords with the identifications of Hu (1964: 35--36), who came to the same conclusion.
Both Nageia formosensis and N. nankoensis were included in the long synonymy of N. nagi (as Decussocarpus nagi (Thunberg) de Laubenfels) by de Laubenfels (1969: 357). His concept of N. nagi, and of other species of Nageia, was very broad.
Acknowledgments. The Royal Botanic Garden, Edinburgh, is supported by The Scottish Office Agriculture, Environment and Fisheries Department. I thank the directors of BM and K for allowing me to examine material, including the type of Nageia formosensis.
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