【摘要】 <正> 鱼网叶(Sagenopteris)的角质层特征颇具系统分类意义。此属建于1838年(Persl),但在此之前已被描述过(Brongniart,1882)。最初误认为蕨类植物;与现代水蕨科(Hydropterideae)苹属(Marsilia)比较。Thomas, H. H.(1925)据角质层特征将此型叶片与共生的含种子器官(Caytonia)和含花粉器官(1937年Harris订为Caytonanthus)联系,建立了开通目(Caytoniales),隶属于种子蕨纲。Harris(1940,1951,1964)更多还原

【Abstract】 Here structurally detailed are two species from the Upper Mesozoic of West Liaoning and North Hebei Provinces representing two cuticle types of the genus Sagenopteris. One of them, S. cf. colpodes Harris (P1. Ⅱ, figs. 8—13; P1. Ⅲ, figs. 14—17) from the Upper Jurassic at the Maoburra Coal Mine in North Hebei Province is generally similar to the typical specimens from the Middle Jurassic of Yorkshire both in morphological features such as the shape of leaflet and the venation and in microstructure such as the sinuous walls of epidermal cells and particularly, the angiospermtype stomata. The other is a new species which can be described as follows:Sagenopteris liaoxiensis sp. nov. (P1. Ⅰ, figs. 1—4; P1. Ⅱ, figs: 1—7; P1. Ⅲ, figs. 1—8)Syntype: Fx-1 (P1. Ⅰ, fig. 4) and B-620 (P1. Ⅱ, fig. 1).Diagnosis: Leaflets 4—6 in palmate arrangement, lanceolate, obovate or elliptical in outline, symmetrical or unsymmetrical, 66—94 mm long and 40—60 mm. wide at the widest portion which is about half as wide as the leaf, narrowing towards its obtuse apex and its base where the lamina contracts cordiformly. Petiole unknown. Beyond the base, a long and thick petiolule extending from the midrib which persists up to or near the tip of leaflet and finally lost in the fine veins. Lateral veins, after arising from the midrib at an acute angle and running parallelly for a distance, abruptly bending ourward till reaching the margins at about 60—80 mm, and then repeatedly branching and anastomosing. Meshes about 8—14mm long and 1—2 mm wide near the midrib while about 1.5—2 mm in isodiameter near the margins.Cuticles rather thin, generally with the lower one thinner than the upper one. Upper cuticle poorly preserved; only showing some obscure nerve-course (P1. Ⅲ, fig. 8), occasionally with one or two abortive stomata surrounded by unthickening subsidiary cells (P1. Ⅱ, fig. 3), and rarely with hair-bases. Lower cuticle clearly showing the sinuous walls of epidermal cells(P1. Ⅲ, fig. 5) and the nerve-course consisting of elongate cells. Epidermal cells in the space between nerve-courses irregular in shape and arrangement, with stomata and hair-bases sparsely dispersing in the space (P1. Ⅲ, fig. 2). Stomata of haplocheilic and monocyclinic types. Guard cells sinking and partially overlapped by 5—6 subsidiary cells neighbouring the pit and thickly eutinizing and elevating about the epidermal surface A fair "rampart" about 30—40 μm in diameter consequently observed in the surroundings of the pit. Hair-based also thickly cutinizing, quadra. or quinque-polygonal, sometimes with a thick ring or some small granules occupying their top. Pappillae unknown. Cuticle in nerve-course or near the midrib regularly consisting of rectangular or elongate cells, with rare or even no stomata present in it.Remarks: Apart from some minor differences in morphology and cuticle, the distinctive features such as the long and thick petiolule of leaflet in morphology and the highly strong "rampant" surrounding the stomatal pit in microstructure distinguish the new species from the rest ones of Sagenopteris except the "S. mantellii" of the Lower Cretaceous in France (Carpentier, 1927, 1938). The French species is the closest relative to S. liaoxiensis sp. nov. but some morphological and microstructural differences prevent them from being identical with each other. However, even the French "S. mantellii" is not really identical with that of Germany (Daber, 1960), from where the typical specimens of S. mantellii were described. Therefore, the nomenclature of the French specimens still need reconsideration, and of course, the present Chinese specimens should be attributed to a new species. Anyhow, both S. liaoxiensis sp. nov. of China and "S. mantellii" af France might represent a special type of cuticle in Sagenopteris.In contrast to the conclusion made by Harris (1935), S. liaoxiensis sp. nov. provides some evidences in connection with the genus Ctenis in cuticular features such as the highly strong "rampart" surrounding the pit, the deeply sinking guard cells, the thick hair-bases, the narrowing aperture, etc.. Furthermore, the connection is solidified by a piece of cuticle from a specimen assigned to Ctenis sp. from the same beds in the Fuxin Coal Mine (P1. Ⅱ, figs. 14—18; P1. Ⅲ, figs. 9—13); the cuticle clearly shows ’the same microstructure as in S. liaoxiensis sp. nov..Localities and age: Fuxin and Bingou Coal Mines in Liaoning Province, Early Cretaceous.更多还原