中文摘要：

文章讨论晚古生代木本石松植物圆印木属Cyclostigma命名中存在的突出问题．包括4个方面：1）圆印木属的合格发表和作者引证；2）圆印木属的异名、同名和替代名；3）圆印木属的保留；4）圆印木属的模式。基于相关原始文献和国际植物命名法规．文中澄清了这些命名问题。Hecr在1871年最早合格发表了，圆印木属．故该属应被引证为Cyclostigma Haughton ex Hcer．1871．（或Cyclostigma Hcer，1871）．而不是文献中通常引证的Cyclostigma Haughton．1860（或1859）。圆印木属不宜归入具叶舌的窝木属Botkrodendron Lindlcy et Hutton．1833．二者相关的生殖器官特征差别也较大。圆印木属的3个同名Cyclostigma Hochst．ex EndL．1842（夹竹桃科Apocynaccac）．Cyclostigma Klotzsch ex Sccm,.1853（大戟科Euphorbiaceae）和Cyclostigma Phil．，1870（茄科Solanaceae）住现代被子植物中已不再使用．Cyclostigma Hochst．ex Endl．被提议废弃，后两者为非法名称．这3者分别是更早合格发表的属名Voacang Thouars．1806．Croton L,.1753和Leptoglossi,Benth．，1844的分类学异名。Cyclostigma Haughton ex Heer因住化石石松植物中广为使用已被提议为保留名，它的模式种为基尔托克圆印木C kiltorkense Haughton ex Heer．为晚泥盆世法门期植物群的重要组分或标志化石．具有十分重要的生物地层学意义。比较而言，圆印木属的替代名Jurinodendron Doweld．2001日后被普遍接受的可能性极小。保留广泛使用的圆印木属Cyclostigma有利于命名的稳定性．而且避免了不必要的重新命名。由于圆印木属模式种的原始标本下落不明．一份保存在爱尔兰部柏林三一学院地质博物馆的标本TCD．6012（采自模式产地）被选为新模式。

英文摘要：

The outstanding nomenclatural problems in the Palaeozoic arborescent lycopsid Cyclostigrna are discussed, which include four aspects.. 1） valid publication and author citation of Cyclostigma; 2） synonym, homonym, and replacement name of Cyclostigma; 3） conservation of Cyclostigrna; and 4） typification of Cyclostigma. Based on the literature and the International Code of Botanical No menclature, these nomenclatural problems are clarified. Heer was the first to validly publish the generic name Cyclostigma in 1871, and thus it should be cited as Cyclostigma Haughton ex Heer, 1871 or Cyclostigma Heer, 1871, rather than Cyclostigma Haughton, 1860 （or 1859） as formerly cited in most literature. Cyclostigma should not be merged into an earlier validly published genus Bothrodendron Lindley et Hutton ,1833, as the latter bears the ligule and distinctive reproductive organ. Three homonyms Cyclostigma Hochst. ex Endl. , 1842 （Apocynaceae）, Cyclostigma Klotzsch ex Seem., 1853 （Euphorbiaceae） and Cyclostigrna Phil. , 1870 （Solanaeeae） are little available for use in Recent angiosperms. Cyclostigma Hochst. ex Endl. was proposed to be rejected while Cyclostig ma Klotzsch ex Seem. and Cyclostigma Phil. were illegitimate later homonyms, the three names of which are the taxonomical synonyms of earlier validly published generic names Voacanga Thouars, 1806, Croton L. , 1753 and Leptoglossis Benth. , 1844, respectively. In view of its widespread use, Cyclostigma Haughton ex Heer was proposed to be conserved, and its type species is C. kiltorkense Haughton ex Heer, indicating biostratigraphic importance in the late Late Devonian （Famennian） flora as an index fossil. In contrast, the wide acceptance of the replacement name J urinodendronDoweld ,2001 will be slim. By conserving a widely used name, it would avoid unnecessary renaming and achieve nomenclatural stability. The location of original specimens of type species C. kiltorkense Haughton ex Heer was unknown, and therefore a neotype （No. ： TCD. 6012?