Nilsonia undulata sensu Stockmans et Mathieu,1939的订正——Nilsonia stockmansiinom .nov.

A NEW SPECIFIC EPITHET NILSONIA STOCKMANSII NOM. NOV. PROPOSED FOR NILSONIA UNDULATA SENSU STOCKMANS ET MATHIEU, 1939

NilssoniaundulataStockmansetMathieu ,1939是NilssoniaundulataHarris,1932的晚出异物同名 ,为此 ,作者为NilssoniaundulatasensuStockmansetMathieu建立了一个新名称。据《植物命名国际规范》 ,属名的原始拼缀Nilsonia应优先于后来拼缀Nilssonia ,因之 ,新名称拼缀为Nilsoniastockmansiinom .

Nilsonia undulata Stockmans et Mathieu (1939, p.92; Pl.XXII, fig.2 et 2a, 3) was created for a cycadophyte fossil plant from the Chao ko chwang Group of Tangshan. The diagnosis of the species was given as follows: “Fronde atteignant au moins 6 cm de largeur, constituée d'un rachis strié longitudinalement et de pinnules espacées, de largeur quelque peu variable, comprise entre 3 et 8 mm, rubanées, se rétrécissant un peu vers la base pour s'élargir ensuite de part et d'autre, les décurrences étant toujours assez peu marquées, extrémité arrondie, souvent asymétrique, le o ^ té inférieur étant falciforme. Nervures bien marquées, quittant le rachis sous un angle droit ou subissant une légère inflexion de faon  suivre un trajet approximativement parallèle aux bords de la pinnule. D'ordinaire une seule bifurcation tout près du rachis; rameaux espacés de 0.25 mm (soit 5 par millimètre).' The original specimens were only two impressions, so it provided no cuticular features of the species. When publishing the new species, Stockmans and Mathieu (1939) obviously overlooked the article written by Harris (1932), so they created a specific epithet as the same as Harris did. In fact, Nilsonia undulata was preoccupied by Harris (1932) for some Mesozoic specimens from the Thaumatopteris zone of Greenland. Besides cuticular characteristics, Harris (1932, p.41—43; Pl.3, figs.3, 8, 9, 11; Text fig.23) gave a specific diagnosis for the gross morphology of Nilsonia undulata Harris as follows: 'Typical leaf petiolate; lamina 15 cm long, 2-3 cm broad, tapering below to the petiole, apex obtuse or emarginate. Surface of lamina usually undulating. Veins arising at an angle of 60°—80°, concentration about 20 per cm, but very variable (extremes 13 at base of large leaf and 35 at apex of small leaf). Lateral veins never branched. ' Obviously, the specimens described by Stockmans and Mathieu (1939) are quite different from those described by Harris (1932), and as a result, Nilsonia undulata Stockmans et Mathieu, 1939 turns into a junior homonym of Nilsonia undulata Harris, 1932. While studying the Permian plant with cuticule similar to some extent to that of the genus Nilsonia , the authors of the present article made reference to the works of Harris (1932) and Stockmans and Mathieu (1939), and found that these two specific epithets constituted a primary homonym. Therefore, the junior homonym Nilsonia undulata Stockmans et Mathieu, 1939 should be abandoned. Here we would like to propose a new specific epithet Nilsonia stockmansii nom. nov. for Nilsonia undulata Stockmans et Mathieu, 1939. The specific epithet is after Dr. F. Stockmans, honouring his palaeobotanical work in the Kaiping basin of China. The diagnosis of the species remains the same as cited above. Considering the absence of a holotype in the publication of Stockmans et Mathieu, 1939, the present authors designate the specimen shown in their Pl.XXII, fig.2 as lectotype. The customary spelling of the generic name was Nilssonia , but recently Kvacek and Knobloch (1997) pointed out that “according to the ICBN rules the original spelling of the generic name Nilsonia is preferred over Nilssonia (Farr et al ., 1979, p.1177; Greuter et al ., 1994).” Following the ICBN reules, the present authors spell the new specific name as Nilsonia stockmansii nom. nov.