Abstract

Gnetalean megafossils were accumulated in the last decade. Taxonomic positions of several of Ephedran megafossil species are, however, controversial, resulting in a complicated nomenclature. Liaoxia Z.Y. Cao & S.Q. Wu, “Eragrostis Z.Y. Cao & S.Q. Wu”, “Chaoyangia Duan”, and their type species “Liaoxia cheniae Z.Y. Cao & S.Q. Wu”, “Eragrostis changii Z.Y. Cao & S.Q. Wu”, “Chaoyangia liangii S.Y. Duan”, were not validly published in the original publication under the Vienna Code. The species “Liaoxia cheniae Z.Y. Cao & S.Q. Wu” was validly published as Ephedrites cheniae S.X. Guo & X.W. Wu but later combined into Liaoxia cheniae (S.X. Guo & X.W. Wu) Z.Y. Cao & S.Q. Wu and further into Ephedra cheniae (S.X. Guo & X.W. Wu) H.M. Liu et al. Some uncertain morphological characters are fundamental to elucidate the taxonomic position of Ephedrites cheniae S.X. Guo & X.W. Wu and “Chaoyangia liangii S.Y. Duan”, e.g. bract number, position, and connation in female cones, seed number and position in a female cone, and morphology of the furcated appendages of reproductive organs of “Chaoyangia liangii S.Y. Duan”.

中文摘要

巨化石在植物起源和演化研究中具有十分重要的價值，但在本世紀之前與現代買麻 藤類可比較的巨化石罕有報導。這種狀況在過去十年中得到了很大的改善，東亞、北美洲、 南美洲和歐洲等地不斷有買麻藤類的巨化石报道，然而，其中一些麻黃類巨化石除了在分 類地位上還有爭議外，在命名上也比較混亂，例如： 「Liaoxia Z.Y. Cao & S.Q. Wu」、 「Eragrostis Z.Y. Cao & S.Q. Wu」、「Chaoyangia S.Y. Duan」及其模式種「Liaoxia cheniae Z.Y. Cao & S.Q. Wu」、「Eragrostis changii Z.Y. Cao & S.Q. Wu」和「Chaoyangia liangii S.Y. Duan」等名稱均沒有合格發表。「Liaoxia cheniae Z.Y. Cao & S.Q. Wu」所代表的種首次被 合格發表為：Ephedrites cheniae S.X. Guo & X.W. Wu，但後來被組合為Liaoxia cheniae (S.X. Guo & X.W. Wu) Z.Y. Cao & S.Q. Wu 和Ephedra cheniae (S.X. Guo & X.W. Wu) H.M. Liu et al.。表示這些種類的分類關係，尚需要一些識別特徵來證明，例如雌毬果中苞片的數目、 苞片的位置、苞片的合生程度及種子數目，和「Chaoyangia liangii S.Y. Duan」中毬果周圍 分叉狀附屬物的形態特徵等。

Keyword: Cretaceous, Ephedraceae, Gnetales, megafossil, nomenclature, taxonomy.