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1.
通过查阅馆藏标本和野外观察,对蹄盖蕨属(Athyrium Roth)的分类性状进行了比较研究,认为根状茎类型、叶上是否具刺、孢子囊群的形状、羽片基部上侧是否具耳状突起和是否具棘头状腺毛等5个形态性状较为稳定,可作为蹄盖蕨属的属下分类性状;叶或羽片的形状及羽片是否具柄等性状可作为分种性状;叶的分裂回数、鳞片和叶柄、羽轴及小羽轴的颜色、被毛多寡及裂片形状等形态性状不适合单独作为蹄盖蕨属属内分种的性状。  相似文献   

2.
贵州产耳蕨属(鳞毛蕨科)一新种—韭菜坪耳蕨   总被引:3,自引:0,他引:3  
骆强 《植物研究》2009,29(2):134-135
描述了贵州耳蕨属一新种,即韭菜坪耳蕨(Polystichum jiucaipingense P. S. Wang et Q. Luo)。新种与栗鳞耳蕨(P. castaneum(Clarke) Nayar et Kaur)相近,但植株较小,叶柄、叶轴上的鳞片淡棕色,孢子囊群着生于全部羽片上而不同。  相似文献   

3.
洪桦枫  常艳芬 《广西植物》2017,37(10):1290-1300
膜叶铁角蕨属隶属于铁角蕨科,全世界约有30种,我国分布有18种,是该属植物的分布中心之一。到目前为止,膜叶铁角蕨属的物种数目和物种分类还存在很大争议,一些物种的界限和定义还模糊不清,为了得到一个自然的膜叶铁角蕨属分类系统,还需要对膜叶铁角蕨属的物种分类做进一步研究。该文在前人研究的基础上,对膜叶铁角蕨属10种植物的形态特征,包括孢子形态特征、叶柄和根状茎上的鳞片形态特征、叶片形态、羽片形状以及叶脉特征等进行详细观察分析,探讨了各个形态特征间的关系以及膜叶铁角蕨属植物的物种分类。结果表明:膜叶铁角蕨属植物的叶片及羽片等形态特征存在很大区别,叶柄和根状茎上的鳞片以及孢子形态的种间差异虽然不大,但其在大小、形状、颜色等方面的细微差别仍可作为部分种类的鉴定依据。该研究结果为膜叶铁角蕨属植物的物种分类及进一步研究提供了重要依据。  相似文献   

4.
以中国荒漠特有植物艾比湖沙拐枣(Calligonum ebi-nuricum)果实形态特征为研究对象,对分布于原产区的同一居群12个样株的果实进行形态特征比较研究。通过每株30粒果实的喙长、果实长度、果实宽度、果实形状、瘦果长度、瘦果宽度、瘦果形状、刺毛长度、头部刺毛长度、两肋间距、两刺间距11个性状指标的数值分析表明:在株内与株间均有变异,株间果实性状变异较株内果实性状变异大;代表果实和瘦果大小指标正相关性极显著(p<0.01);两肋间距与瘦果形状呈负相关(r=-0.297**,p<0.01)。研究结果证明:其果实形状和瘦果形状(长度、宽度及长宽比)较为稳定,可作为艾比湖沙拐枣的分种依据,而其它果实性状可塑性较大,只能作为分类的参考。该研究结果可供沙拐枣属其它种的准确分类参考。  相似文献   

5.
该文采用光学显微镜,首次对九种瘤足蕨属植物的叶柄和羽片横切面进行了解剖学比较研究。结果表明:九种瘤足蕨属植物在叶柄中部横切面的表皮、基本组织和中柱以及营养叶羽片的表皮、叶肉和主脉等结构特征是相似的,如叶柄中部横切面的表皮不被毛或是鳞片,表皮细胞形状呈类圆形,具有厚壁组织,中柱为周韧型维管束;营养叶羽片横切面的气孔只分布于下表皮,表皮细胞形状呈扁平状,主脉的结构类型属于周韧型维管束。在系统的演化中,瘤足蕨与桫椤科植物有一定的亲缘关系,两者既有相似的特征但也表现出一定的差异,支持瘤足蕨属是一个自然分类的观点。九种瘤足蕨属植物叶柄中部横切面形状有梯形、椭圆形和三角形,叶柄中部横切面维管束的形状成"U"字形、"V"字形或"品"字形;维管束数目1个或3个;维管束结构中的木质部成"八"字形、"U"字形或"一"字形;羽片主脉下侧形成了以三角形、弧形或梯形的突起;叶柄中的木质部形态有两种,即典型的海马形状以及非典型的海马形状,其中典型的海马形状的特点为叶柄的木质部两侧都呈现弯曲成钩的形态,非典型的海马形状特点为2个木质部束的两侧都未出现弯曲成钩的形态或者是其中的一个木质部一端无弯曲成钩的形态,这些形态解剖特征稳定且具类群特异性,为瘤足蕨属植物的分类和系统学研究提供了新的依据。同时,依据其叶柄和羽片横切面解剖叶柄学特征列出了瘤足蕨属植物分种检索表。  相似文献   

6.
乌毛蕨科3种植物配子体发育的研究   总被引:1,自引:0,他引:1  
通过人工培养的方式,详细记录了乌毛蕨科(Blechnacea)具代表性的3个种,即乌毛蕨(Blechnum Orientale L.)、狗脊蕨(Woodwardia Japonica (L.F)Smith)和苏铁蕨(Brainea insignis (Hook)J.Sm)的配子体发育全过程,附特征性结构照片37幅。实验结果基本支持秦仁昌主要依据孢子体形态的分类观点。为乌毛蕨科的研究积累了配子体发育方面的详实资料。  相似文献   

7.
对中国凤尾蕨属44个分类群进行孢粉学与叶表皮形态学研究。结果表明:在属的水平,该属的孢子形态稳定。根据赤道环的有无和脊类纹饰的情况,该属可划分成6种类型。但这与该属的孢子体形态不相关。在属和种的水平,该属的气孔器类型均具有较高的稳定性,大部分种类以极细胞型和腋下细胞型为主。气孔器密度、面积、长宽比这3个定量特征在属和种的水平上稳定性都较差,因此不具有分类学价值。基本气孔器类型在种间重复性较高,可作为该属稳定的形态特征之一,在属的水平上具有一定的分类学价值,但不宜作为该属属下的分类学依据。综合两方面的数据,对部分疑似种进行初步的分类学处理,并探讨了易混淆种的分类学关系。  相似文献   

8.
Pecopteris lativenosa Halle是栉羊齿属中羽叶形态变化十分显著的一个种。作者在详细观察的基础上,尝试性地运用定量统计和方差分析方法判定该植物具有代表性的各项特征,提出了普遍存在的5种小羽片类型、6种末次羽片类型和2种末二次羽片类型,以及各类型小羽片、末次羽片、末二次羽片和末三次羽片的空间分布关系,并以此为依据绘制了Pecopteris lativenosa Halle三次羽状复叶复原图。这一复原图能够解释以往发现的Pecopteris lativenosa Halle标本所属类型。  相似文献   

9.
凤丫蕨属(Coniogramme Fée)种间界限模糊,存在过渡类型,是蕨类植物中分类比较困难的类群之一。黑轴凤丫蕨(C.robusta(H.Christ) H.Christ)是凤丫蕨属植物中比较特殊的种类之一。本文在标本考证、野外考察和微形态研究的基础上对该种的分类进行了订正。将假黑轴凤丫蕨(C.pseudorobusta Ching et Shing)和新黑轴凤丫蕨(C.neorobusta Ching et Shing)归并到黑轴凤丫蕨。同时对该种下的两个变种黄轴凤丫蕨(C.robusta var. splendens Ching et Shing)和棕轴凤丫蕨(C.robusta var. rependula Ching et Shing)重新定义模式标本。  相似文献   

10.
利用光学显微镜和扫描电子显微镜,观察了新疆委陵菜属(Potentilla L.)锥状花柱组(Sect.Conostylae(Wolf)Yü et Li)15种委陵菜植物叶表皮的微形态特征。对其叶表皮毛的类型、表皮细胞的形状及大小、气孔器的分布、气孔器类型、气孔形状、气孔大小、气孔密度、气孔指数、气孔外拱盖形态及其纹饰等指标进行分析:有几种植物叶的上表皮无气孔,而下表皮均有气孔器的分布,形状为长椭圆形、椭圆形、宽椭圆形和近圆形;气孔器的类型多为短平列四细胞型、无规则四细胞型、无规则型、围绕型和辐射型;表皮毛的类型为针状毛、带状柔毛和腺毛;表皮细胞分为不规则形和多边形;表皮毛特征、叶片表皮细胞的形状、垂周壁式样、气孔器的形状类型、气孔密度指数及蜡质纹饰等存在差异,可作为亚属间及种间分类的依据。  相似文献   

11.
The unique leaf structure of the genus Anemia with its upright fertile basal pinnae has been interpreted as derived from the typical fern leaf with unmodified basal pinnae. Reported herein for the first time is the leaf morphology of a species, Anemia colimensis Mickel, which shows the most primitive condition known in the genus and clearly confirms the course of evolution. The fertile pinnae are but little modified in size, lamination, and posture. Although A. colimensis has characters of two subgenera, it is shown to be a primitive element in subgen. Anemiorrhiza and not a member of subgen. Coptophyllum as previously reported.  相似文献   

12.
Charliea is a new genus (type-species: C. manzanitana), based on pinnately compound leaf material from the richly fossiliferous Virgilian (Upper Pennsylvanian) shales of the Kinney Brick Company quarry near Albuquerque, New Mexico. In several features Charliea resembles Russellites or a zamioid cycad. It has linear-oblong pinnae with broad, oblique attachment and a truncate tip, which is deeply incised to form two to four nearly equal lobes. The venation is simple, parallel, and sparingly dichotomous, each vein ending at the distal margin. The Kinney beds also contain Plagiozamites planchardi, another zamioid form with parallel-veined pinnae, differing from Charliea chiefly in having rounded tips and veins ending in the denticulate margins. An unnamed third form (genus B) in the Kinney beds has long, narrow pinnae with parallel veins and blunt tips; this strongly resembles the Mesozoic conifer Podozamites, but may just as well represent a cycadophyte. Another unnamed taxon (genus A), from an Upper Pennsylvanian deposit in Jack County, Texas, resembles genus B or Russellites in general shape and venation, but the critical distal margins are unknown. In their single-ordered parallel venation, these four foliar types contrast sharply with the two-ordered pinnate venation of most Pennsylvanian fern-like leaves, and seem to foreshadow Mesozoic morphologies. This tendency toward precocious evolution of parallel-veined foliar form in North America is also expressed by a single occurrence of the Asiatic, Permian genus Tingia in the Lower Pennsylvanian of Utah, and by the presence of the predominantly Triassic cycadeoid genus Pterophyllum in the Lower Permian of Texas.  相似文献   

13.
A fossil plant discovery from the Price (Pocono) Formation of southeastern West Virginia provides new information on the poorly known compression floras of the Lower Mississippian of North America. The new plant described herein consists of long tapering bipinnate fronds with imbricate basal pinnae, planate apical pinnae, and unlobed, elliptical to obovate pinnules with open dichotomous venation. Veins concentrated in the medial region of the pinnule curve toward the lateral margin, suggestive of an early stage in the evolution of a midrib. Pinnules exhibit a distinctly revolute or otherwise reinforced margin. The exceptional length of some fronds (over 1m) and pinnule size (some over 3cm by 2cm) strongly contrast with the generally diffusely branched fronds and small or highly dissected pinnule morphology that typify Early Mississippian leaf taxa. A new generic assignment, Charbeckia macrophylla, is thereby justified. The rigid appearance of the tapering rachis, the imbricate pinnae that appear to have resisted compression, and the reinforced pinnule margins imply thick evergreen leaves, perhaps adapted for drought tolerance. A possible Calamopityalean affinity is indicated by the size of the fronds and the stout petioles, which fall within the expected size range of the Kalymma-type petiole bases described from the nearby New Albany Shale of Tournaisian age.  相似文献   

14.
This review of the genus Dichopteris De Zigno is based on the original fossil specimens collected from the Lower Jurassic of the Grey Limestones of Veneto (Northern Italy). The cuticular diagnosis of the genus is emended and only Dichopteris visianica De Zigno is retained within the genus. In addition, transverse and longitudinal sections of cuticles examined using a transmission electron microscope (TEM) indicate close similarities between D. visianica and other pteridosperm cuticles, especially the occurrence of granules arranged in areas of different densities in the epidermal cells and stomatal apparatus. Moreover, the dichotomy and the impressive size of the frond of D. visianica imply a specific architecture with a typical arrangement of the pinnae and pinnules. They preclude an herbaceous habit for the plant. Finally, architectural, microstructural and ultrastructural observations are consistent with palaeoclimatic and palaeoenvironmental data, and most probably support an understorey habit for D. visianica .  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 149 , 313–332.  相似文献   

15.
郑芳勤 《植物学报》2001,18(2):246-250
Cycas属植物羽状复叶上的小羽片,是从不开叉向二叉开裂逐步发展的。二叉开裂后,小羽片继续进一步发展、进化,在其开叉分裂的小羽片上再次二叉开裂,成为三回、四回、五回二叉开裂的裂片(小叶),最后小羽片发展到多回开裂,成为Cycas属植物羽状复叶上最进化的一种小羽片类型。着生这种进化类型小羽片的叉叶类苏铁是Cycas属植物中最进化的种群。  相似文献   

16.
Frond members belonging to the monostelic seed fern genus Heterangium have been found in Pennsylvanian age coal balls collected in the Illinois Basin. Petioles bear small pinnae below a dichotomy which produced a bipartite frond. Pinnules of the Sphenopteris obtusiloba type are borne on secondary pinnae. The anatomy of each pinna order and the pinnules is described.  相似文献   

17.
叉叶类苏铁是苏铁属植物中最进化的种群   总被引:3,自引:0,他引:3  
郑芳勤 《植物学通报》2001,18(2):246-250
Cycas属植物羽状复叶上的小羽片,是从不开叉向二叉开裂逐步发展的,二叉开裂后,小羽片继续进一步发展,进化,在其开叉分裂的小羽片上再次二叉开裂,成为三回,四回,五回二叉开裂的裂片(小叶),最后小羽片发展到多回开裂,成为Cycas属植物羽状复叶上最进化的一种小羽片类型,着生这种进化类型小羽片的叉叶类苏铁是Cycas属植物中最进化的种群。  相似文献   

18.
Compressed specimens of the fern Osmunda are described from the Triassic of the Allan Hills, Antarctica. The specimens consist of a once pinnate, deeply pinnatifid fertile frond as well as several sterile specimens. Six pinnae are present on the partial fertile rachis, with two sterile pinnae above four fertile pinnae. Both sterile and fertile specimens are virtually identical to the modern species Osmunda claytoniana. Entire fronds are fragmentary; the longest is 21 cm in length. Sterile pinnae are alternate and deeply pinnatifid, with slightly toothed pinnules and dichotomous venation. Fertile pinnae are 1-1.3 cm long, once pinnate, and lack vegetative lamina. Sporangia are clustered, each 300-375 um in diameter, and possess a transverse annulus 6-8 cells long; dehiscence is by a vertical slit. Fronds arise from a rhizome 4 cm long by 1 cm wide; two croziers are present on the rhizome. Two frond segments up to 6 cm long and three deeply pinnatifid pinnae are present on the uppermost part of one rachis. Pinnules are ~4 mm long and 2-3 mm wide. The presence of this Osmunda species in the Triassic demonstrates stasis of frond morphology, both fertile and vegetative, for the genus.  相似文献   

19.
A systematic survey of the leaf anatomy of 51 taxa in the palm genus Syagrus was made. Cross sections of the middle pinnae of each taxon were embedded, cut, stained, and mounted on slides. Criteria used to distinguish species were based mainly on differences in the laminar surface and hypodermis: frequency and location of various sized veins; frequency, shape, and location of nonvascular fibers; size and shape of midrib and main vascular bundle; and size and shape of expansion cell tissue. The included key to the species employs mostly these characteristics. Each taxon is listed under subgenera and sections in the order presented in a previous article, where gross morphology was used as the basis of classification. Relationships between species of each subgenus and section are discussed in terms of the original arrangement of each group and needed changes. It is significant that certain evolutionary sequences have become unfolded which were not apparent by use of morphological characters alone. Although all relationships have not been completely worked out, this survey has resulted in a revision of my original classification of the genus Syagrus and at the same time has also corroborated certain alignments of species previously based on gross morphology.  相似文献   

20.
The genus Osmunda L. contains approximately 10 extant species widely distributed in tropical and temperate regions, with the greatest concentration of species in East and Southeast Asia. Osmunda is characterized by dimorphic or commonly hemidimorphic fronds with dimorphic pinnae. Its geological history has been traced back to the Triassic. Most records of the genus are based on rhizomes and rarely on pinnae bearing sporangia and spores. Here, we describe fossil pinnae, sporangia, and spores of Osmunda lignitum (Giebel) Stur recovered from the middle Eocene of the Changchang Formation in the Changchang Basin, Hainan Island and the Youganwo Formation in the Maoming Basin, Guangdong, South China. The fossils closely resemble the extant Osmunda banksiifolia (C. Presl) Kuhn of the subgenus Plenasium on the basis of their morphological and anatomical structures. The present occurrence of O. lignitum indicates subg. Plenasium flourished and extended from the high latitude regions such as Northeast China to the low latitude areas of South China during the middle Eocene. Large numbers of specimens described here also indicate that Osmunda was the dominant understory fern element beneath mixed evergreen broad-leaf angiosperm and gymnosperm forests living in a warm and humid environment.  相似文献   

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