The Pollen Morphology in Relation to the Taxonomy and Phylogeny of Fagaceae

The present paper deals with the pollen morphology of 103 species belonging to sixgenera-Castanea, Castanopsis, Lithocarpus, Quercus, Fagus and Trigonobalanus in threesubfamilies-Castaneoideae, Quercoideae and Fagoideae. All pollen grains were examinedunder light microscope and scanning electron microscope, and those of some species were ex-amined under transmission electron microscope. The results may be summarised as follows:1. Pollen morphology of Fagaceae, seems to support division of the family into threesubfamilies. Fagoideae, Castaneoideae and Quercoideae.2. Four types of pollen grains are recognized in Fagaceae:1) Fagus-type (representative genus: Fagus): pollen granis are oblate-sphaeroidal,(31.5-39.9) x (35.7 46.2) μm in size, 3(-4)-colporate, peritreme or goniotreme, granulate-ornate under LM., granulate or verrucate under SEM.2) Trigonobalanus-type (T. doichangensis): pollen grains are suboblate-sphaeroidal,(23.1-29.4) ×(25.2-29.4) μm in size, 3-colporate, goniotreme, obscurely granulate-ornateunder LM, densely granulate or verrucate under SEM.3) Quercus-type (Quercus): pollen grains are subspheroidal-subprolate, (21-44.3)× (16.8-39.9) μm in size. 3-colporoidate (-3-colpate), peritreme, crassgranulate or finely-gra-nulate under LM, tuberculate verrucate or spinate under SEM.4) Castanea-type (including Castanea, Castanopsis, Lithocarpus): Pollen grains areprolate-supraprolate, (14.7-23.1)×(10.5-16.8)μm in size; 3-colporate, peritreme, obscu-rely ornate or subpsilate, under LM, rugulose, striate-rugulate or crass-striate under SEM.3. Pollen grains of Cyclobalanopsis age very similar to those of Quercus, and there-fore we support the treatment of Cyclobalanopsis as a subgenus of Quercus.4. On the basis of shape, type of aperture and exine structure, pollen of Trigonobalanusis distinguishable from those of the other genera in Fagaceae and it may be a new type of Fagaceae;5. On the basis of pollen morphology, morphological characters and geological stratification a scheme of phylogeny of Fagaceae is here presented.     

A Study on Pollen Morphology and Ultrastructure of Subfamily Castaneoideae (Fagaceae) in China

The present paper describes the pollen morphology of 45 species of the subfamily Castaneoifeae (including genera Castanea, Castanopsis and Lithocarpus) from China. The pollen grains were all examined with light microscope, scanning electron microscope and transmission electron microscope. Pollen grains of the subfamily are prolate, subprolate or perprolate, (14.7-23.1)× (8.4 -18.9) μm in size, 3-colporate, the exine in 2-layered, 0.9-1.9μm thick, indistinctly ornate, striate-rugulose or crass-striate, sexine and nexine almost equal in thickness, the sexine consists of tectum, bacules and endonexine under TEM. On the basis of very similar pollen shape, pollen size, type of aperture and exine structure and also other characteristics of plant morphology of the genera Castanea, Castanopsis and Lithocarpus, the present authors tend to support the opinion that they all fall into the samesubfamily, Castaneoideae.     

On the Pollen Morphology and Systematic Position of Trigonobalanus doichangensis

The present paper describes the pollen morphology of Trigonobalanus doichangensis (A. Camus) Forman of Fagaceae. Comparative study on pollen grains was carried out by means of light microscope, scanning and transmission electron microscope. The pollen grains of T. doichangensis are subspheroidal or suboblate but in polar view they are subtriangular, and in equatorial view they are subcircular they are 27.3, 23.1-29.4)×27.3(25.2-29.4) μm in size and 3-colporate goniotreme. The exine is 2-layered, 2.4-4.2μm, thick in apocolpia. The sexine cosists of tectum, bacules and endonexine under TEM. On the basis of pollen shape, type of aperture and exine structure the pollen grains of T. doichangensis are distinguishable, from those of other genera in Fagaceae and it may belong to a new type of Fagaceae.     

Pollen Morphology of Quercus L. in China

The present paper describes the pollen morphology of 31 species of the genus Quercus from China. The pollen grains were all examined with light microscope and scanning electron microscope, and those of some species under transmission electron microscope. Pollen grains of the genus are spheroidal or subspheroidal, 16.8-50.4μm in diameter, 3colporoidate or 3-colpate. The exine is 2-layered, 0.4-1.8μm thick, sexine thicker than nexine, granulated tuberculate or verrucate.     

A Systematic and Evolutionary Study of Zizania L. (Gramineae) Pollen Morphology

This paper deals with pollen morphology of Zizania L. and its relatives. A total of 7 genera, 13 species, 3 varieties and 1 form were examined under light microscope and scanning electron microscope. The results are as follows: 1. The genus Zizania belongs to tribe Oryzeae as shown by pollen characters, i, e. subspheroidal to ovoid in shape, monoporate, exine two-layered, with minute granules under LM. 2. The evolutionary trend of these taxa seems to be from minute granules free (Zizania latifolia, Z. texana, Zizaniopsis milicea and Oryza sativa) to minute granules aggregated in a group of 2-4 (many) (Zizania aquatica, Z. palustris, Leersia hexandra etc.). The genus Zizania may be derived from the ancient stock which has also given rise to the genus Oryza, and therefore parallel evolution may have taken place in Oryzeae, i. e. from perennial species to annual species in Zizania in one line, and from the genus Oryza to Leersia, Chikusichloa etc. in the other. 3. The characters of pollen morphology under LM and SEM support the division of the genus, Zizania into 4 species, 2 subspecies in the world, i. e. Z. latifolia (Griseb.) Turcz. ex Stapf, Z. texana Hitchc., Z. aquatica subsp. aquatica, Z. aquatica subsp. brevis (Fassett) S. L.Chen, Z. palustris subsp. palustris, and Z. palustris subsp. interior (Fassett) S. L. Chen.     

螺序草属(茜草科)的花粉形态

首次对螺序草属(Spiradiclis B1.)的11种和1变型共16份植物的花粉样品在光镜和电镜下进行了观察。结果表明,本属植物花粉为单粒,小型和中型花粉,近球形至椭球形,辐射对称,常具3孔沟,偶为4孔沟,外壁表面纹饰为孔状。花粉外壁由不连续的具穿孔的覆盖层、柱状结构和基层组成,内外壁明显。此外,本属植物的花粉具有花粉2型和“芽状”结构的现象。螺序草属植物的花粉形态在属下分类上有一定的局限性,但是在个体的系统发育上却可以提供极有价值的信息,如具有花粉单型的种类比花粉二型的种类进化。     

延龄草科四属花粉形态的研究

对延龄草科重楼属Paris L.延龄草属Trillium L.Medeola L.属和Scoliopus Torr.属以及百合科百合属Ｌilium L.和萱草属Ｈemerocallis L.花粉进行了光镜和电镜的观察和比较。结果表明,在延龄草科中,重楼属,Medeola属和Scoliopus属花粉具有较多的相似性：具单一远极沟,极面观椭圆形,外壁为网状纹饰或皱波－网状纹饰。而延龄草属花粉与它们的差异则较大,为圆形,无萌发孔,外壁非网状纹饰,而是颗粒状,疣状,芽孢状,星状和微刺状等纹饰。百合属中的Lilium michauxii和萱草属中的金针菜Hemerocallis citrina花粉均为单一远极沟,外壁表面为网状纹饰。但其网脊特别粗,具不规则突起并形成棱角（H.citina)或由许多排列成念珠状的、形状不一的分子组成（Lilium michauxii),结构特别复杂。就其萌发孔类型和纹饰特征看,它们与延龄草科中的重楼属,Medeola属和Scoliopus属花粉具有较多的性。花粉外壁的层次结构在延龄草科各属之间（延龄草属除外）,甚至在延龄草科与百合科之间均没有多大的差异。     

Studies on Pollen Morphology in Tiliaceae of China

Pollen morphology of 44 species representing 9 genera of Tiliaceae in China was examined under light microscope, 10 of them were observed with scanning electron microscope. Nine genera involved in this paper are: Colona. Corchoropsis, Corchorus, Excentrodendron, Grewia, Hainannia, Microcos, Tilia and Triumfetta The pollen grains of Tiliaceae are eurypalynous. Based on the aperture type and ornamentation, they may be grouped into four types: (1) The Grewia type, pollen grains tricolporate: Colona, Corchorus, Grewia, Microcos and Triumfetta, (2) The Tilia type, pollen grains brevitricolporate: Hainania and Tilia, (3) The Corchoropsis type, pollen grains triporate, spinate: Corchoropsis, and (4) The Excentrodendron type, pollen grains triporate, reticulate: Exce ntrodendron. The significance of pollen morphology in taxonomy of Tiliaceae is discussed. The palynological data seem to support the separation of Microcos from Grewia and the transfer of Corchoropsis to Sterculiaceae from Tiliaceae.     

Studies On the Pollen Morphology of the Genus Iris in China

In this paper, pollen grains of 32 species of the genus Iris in China were examined under light microscope and scanning elrctron microscope. Pollen grains in Iris of China are navicular or subspheroidal. According to the characters of aperture and shape, pollen grains may be divided into four types: (1) Monocolpate (distal): pollen grains navicular or subspheroidal, exine reticulate. (2) Monocolpate-colpoidal: pollen grains subspheroidal, exine pilate. (3) 2-syncolpate: polen grains subspheroidal or navicular, exine reticulate. (4) No aperture: pollen grains subspheroidal; exine verrucate. The evolutional trends of aperture and exine ornamentation are traced and systematic po-sitions of some species are discussed based on characteristics of pollen grains and other organs.     

大戟科叶下珠属花粉形态的研究

对叶下珠属Phyllanthus Linn.13种植物花粉进行了光学显微镜和扫描电镜的观察。研究表明,本属花粉虽然在大小、形状和外壁纹饰等方面有不同程度的差异,但差异最大的还是在于萌发孔类型上。可以把本属花粉分为3孔沟,4－5孔沟,多孔沟,散沟（沟短而纺锤形或近圆形）和散孔等类型。这些萌发孔类型虽然与李秉滔在中国植物志第44卷中所划分的组不很吻合,但或多或少有一定的相关性,并且对于属下的分类具有一定的意义。在外壁纹饰方面,均为网状纹饰,可分为具粗网眼,细网眼和中等网眼等几种类型。但纹饰类型在组间或种间的差异不大明显。     

Pollen Morphology of Impatiens L. (Balsaminaceae) and Its Taxonomic Implications

Two forms of pollen morphology of Impatiens L. (Balsminaceae) have been described before: 3-colpate and 4-colpate pollen grains. Pollen grains of 13 species of Impatiens on Mt. Omei were examined under SEM for the first time and both forms were observed here, which imply the diversity of species in this region. Of the two forms, 3-colpate one is quite similar to that of the genus Hydrocera Blume (Balsaminaceae) in external morphology. This relation also exists between the 3-colpate pollen group and Hydrocera in habit, habitat, and distribution, etc. It is supposed that the group with 3-colpate pollen type is a natural one, and may have a close relationship with Hydrocera. The pollen morphology is of important significance in classification of the taxa and evaluation of systematic position in the fami-ly balsaminaceae.     

Studies on Pollen Morphology and Taxonomy of Lespedeza and Its Allied Genera from NE China

The pollen morphology of 11 species and 1 variety in the genus Lespedeza and its allied genera (Campylotropis, Kummerowia) from NE China was examined under light and scanning electron microscopes. 1. Lespedeza Michx. (plate 1:1-6; 2:1-6; 3:1-6; 4:1-2) Pollen grains prolate, rarely subprolate or spheroidal, elliptic or rarely suborbicular in equatorial view, 3-lobed-rounded in polar view, tricolporate, colpus margins smooth or jagged. Polar axis 20.7-33.1μm long, equatorial axis 15.4-20.9 μm long. Exine reticulate or foveolate, lumina verrucose or smooth under SEM. 2. Campylotropis Bge. (plate 4:3-4) One species in NE China, C. macrocarpa (Bge.) Rehd. Pollen grains prolate, elliptic in equatorial view, 3-lobed-rounded in polar view, 3-colporate, colpus linear, 25.1μm long, 1.79μm broad, colpus margins jagged, with a series of verrucae equal in size along one side visible under SEM. Polar axis 19.7μm long, equatorial axis 14.6μm long. Exine reticulate, lumina nearly rounded, verrucose at periphery under SEM. 3. Kummerowia Schindl. (plate 4:5-6) Pollen grains spheroidal, oblate or prolate, elliptic in equatorial view, obtuse-triangular in polar view, tricolporate, colups linear, 25.1μm long, 2.01μm broad, colpus margins sinuate. Polar axis 24.7-27.9μm long, equatorial axis 19.7-26.6μm long. Exine reticulate or subreticulate, lumina nearly rounded, with verrocae visible under SEM. According to the pollen morphology of Lespedeza and its allied genera, the division of Lespedeza (s. lat.) into Lespedeza (S. str.), Campylotropis and Kummarowia by Schindler (1912) is reasonable. The subdivision of Lespedeza (s. str.) into Sect. Macrolespedeza and Sect. Lespedeza by many botanists, and the treatment of Lespedeze juncea (L. f.) Pers. var. inschanica Maxim. as an independent species (i.e. Lespedeza inschanics (Maxim). Schindl.) are also supported by the pollen morphology shown in the present work.     

Pollen morphology of the tribe Cynoglosseae of Boraginoideae (Boraginaceae) in China

Pollen morphology of 16 Chinese species representing 7 genera in the tribe Cynoglosseae of Boraginoideae(Boraginaceae) was examined under LM and SEM, and 5 species under TEM. Pollen grains are cocoon-shaped, rarely subprolate, prolate or ovoid, very small, 7～ 15.7μm× 3.5 ~ 13.9 μm in size, P/E = 1.6～2.02; 3-colporate apertures alternate with 3-pseudocolpi, with equatorial endocingulus except those in Bothriospermum; exine surface is usually smooth, with or without perforations in two poles, rarely with tuberculate ornamentation; exine is rather thin and includes ectexine and endexine, while ectexine consists of imperforate tectum, columellae and foot-layer. The tribe Cynoglosseae has many common characters of pollen grains, but there are some differences among genera. A key to the genera is given based on pollen morphology. Bothriospermum, without endocingulus, may be a primitive genus in this tribe, and its pollen morphology is more similar to that of Eritrichieae than to Cynoglosseae, thus it seems more reasonable to put it into Eritrichieae. Solenanthus may be the most advanced genus in the tribe Cynoglosseae for its pollen grains of sub-isopolar and ovoid shape.     

广义飞蛾藤属(旋花科)花粉形态

对广义飞蛾藤属Porana s.l.18个分类群的花粉进行了光学显微镜和扫描电镜观察。除前人报道过的7种1变种外,其余均为首次报道。根据花粉粒的大小、形状、外壁纹饰、沟膜特征,该属花粉可细分为4个类型。研究结果不支持Staples(1993)把该属分为4个独立属的观点,而认为在属内划分为4个亚属较为合理。除毛果飞蛾藤外,花粉形态支持Staples对其它种、变种的归并。从花粉萌发孔类型上看,广义飞蛾藤属在旋花科内应处于较为原始的位置。     

Studies on Pollen Morphology and Exine Ultrastructure in Cephalotaxaceae

The pollen morphology of Cephalotaxaceae was examined with LM, SEM and TEM. Pollen grains in this family are spheroidal or subspheroidal, rounded in polar view, but usually wrinkled with irregular shape. Pollen size is 22.6- 34.8 μm in diameter. There is a distinct or indistinct tenuity on distal face. The tenuity occasionally slightly rises above the outline of pollen grains, but often sukened. Exine rather thin, 1—1.5μm thick, layers obscure, surface of pollen grains is nearly psilate or weakly granulate. Under SEM exine is covered with fine and dense granules, and sparse Ubisch bodies are found on the granular layer. The Ubisch bodies are provided with minute gemmate processes on the surface. Acorrding to our observation under TEM, exine consists of ectexine and lamellate endexine, with the former divided into outer ectexine of granules densely arranged and inner ectexine of loosely arranged microgranules. Granules of the outer ectexine are relatively thick, and connected with each other, forming a structure just like tectum or separate from each other. Microgranules of the inner ectexine are distinct or indistinct. Endexine is provided with 5- 7 lamellae. As far as information of pollen morphology is concerned, Cephalotaxus oliveri is rather special in the Cephalotaxaceae. First, the tenuity in pollen grains occupies one half of the distal part, much larger than that of the other species in the family. Second, the ectexine in Cephalotaxus oliveri may be divided into two distinct layers, outer ectexine and inner ectexine. The former is made of a layer of sporopollenin masses, which are connected with each other to form tectumlike structure, while the latter consists of a layer of loosely arranged granules or small segments of sporopollenin. The inner ectexine is different from that of other species by having a thicker layer of sporopollenin granules. Based on these two features, we support the division of Cephalotaxus into two Sections, Sect. Pectinatae and Sect. Cephalotaxus. Pollen grains of Cephalotaxaceae are similar to those of the Taxaceae in having spheroidal shape and the tenuity on its distal face. These characteristics strengthen the evidence for a close relationship between the Cephalotaxaceae and Taxaceae. Although pollen grains of the Cephalotaxaceae and Taxaceae are similar in some characteristics, they have obvious differences in , for example, size of tenuity, the fine structure of Ulbisch bodies and of the outer and inner ectexine. On the basis of pollen morphology, the present author considers theCephalotaxaceae slightly more primitive than the Taxaceae.     

中国紫草科紫草亚科琉璃草族花粉形态的研究

对中国紫草科Boraginaceae 紫草亚科Boraginoideae琉璃草族Trib．Cynoglosseae 7属16种的花粉形态进行了光学显微镜和扫描电镜观察,并对其中5种的花粉外壁超微结构进行了透射电镜观察。该族花粉为茧形,少数为近长球形、长球形或卵球形;体积很小,大小为7～15.7μm×3.5～13.9μm,P／E=1.6～2.02;三孔沟和三假沟相间排列;除斑种草属Bothriospermum Bge．外,均有赤道环带;外壁常光滑,两极具或不具穿孔,少数具小瘤状纹饰;外壁较薄,包括外壁外层和外壁内层,外壁外层又由完全覆盖层、柱状层和基层组成。以上表明该族花粉有很多共同特征,但属之间还是有区别。文中作了花粉分属检索表。在该族中,斑种草属的花粉没有赤道环带,表明它是比较原始的类群。它和齿缘草族的花粉更相似,因此把它放在齿缘草族Trib．Eritrichieae比放在琉璃草族似乎更合适。长蕊琉璃草属SolenanthusLedeb．由于花粉卵球形、亚等极,可认为是琉璃草族中最进化的属。     

角蒿属(紫葳科)的花粉形态

对角蒿属(Incarvillea Juss.)14个种(4变种,2居群)的花粉进行了扫描电镜观察。角蒿属花粉形态较为相似,为单粒花粉,花粉粒扁球形至近球形,外壁表面同时具有近刺状和穴状两种纹饰。大小在28～51μm之间,萌发孔为多沟型,6～10沟,沟长度不等,沿赤道分布,一些种类中沟多少弯曲使萌发孔成螺旋状,沟末端在极面上多少连接形成合沟。角蒿属内种间花粉形态上的相似性说明了角蒿属应为一单系类群,而对于角蒿属下单元划分及种间的系统有着有限的意义,波罗花亚属花粉明显大于其它两个属,花粉形态特征也显示了它与角蒿亚属关系较近。同时,研究结果不支持将角蒿属放在硬骨凌霄族(Tecomeae)。     

国产蔷薇科绣线菊亚科的花粉形态

本文报道了国产蔷薇科绣线菊亚科(Spiraeoideae)8属9种植物花粉形态。该亚科花粉近球形,极面观三裂圆形。花粉通常较小,最小花粉见于Spiraeapurpurea,为1487(1275～1658)μm×1517(1275～1734)μm,其中Physocarpusamurensis的花粉比较大,为2797(1989～3825)μm×3091(2677～3366)μm。三孔沟,内孔为长方形,部分种内孔明显外突。沟较长,两端较窄,在Physocarpusamurensis观察到合沟现象。合沟出现时通常三沟在一极汇合,在另一极常不汇合。花粉外壁具穴状、条纹-穴状、条纹-网状、条纹状等数种纹饰。迄今为止,在Rosaceae观察到的所有花粉外壁纹饰中,除较为特化的刺状纹外,其余纹饰在该亚科均存在。在Rosaceae所有的花粉外壁纹饰中,穴状纹饰可能是较为原始的类型,条纹状-网状和条纹状依次是较为进化的,而刺状是最进化的纹饰。在Spiraea中,外壁纹饰有相对进化的条纹-网状和条纹状,然而未观察到穴状这一最原始类型,这表明该属及其属下种的分化程度可能较高。但因Spiraea所含种数较大,这一推论有待进一步深入论证。此外,花粉形态特征支持Takhtajan(1997)关于Spiraeoideae亚科下族与属的排序。     

Pollen Morphology of Cyclobalanopsis and Its Relation to Quercus

The present paper deals with pollen morphology of 19 species belonging to Cyclobalanopsis and of 31 species belonging to Quercus from China. All pollen grains were examined under light microscope and scanning electron microscope, and those of 4 species of Cyclobalanopsis and of 8 species of Quercus were examined under transmission electron microscope. Pollen grains of Cyclobalanopsis are spheroidal or subspheroidal, 25.2(18.9-31.5) ×23.1 (16.8-27.3) μm in size. Mostly 3-colporoidate, rarely 3-colpate or 3-colporate. The exine is 2-layered, 1.1-1.9 μm thick, sexine thicker than nexine, finely granulate under LM, granulate, spinulate, verrucate under SEM. Pollen grains of Cyclobalanopsis and of evergreen members of Quercus are very similar to each other in size, aperture and ornamentation of exine, but there are some differences in pollen grains between Cyclobalanopsis and deciduous members of Quercus. Therefore, Pollenmorphology supports the treatment of Cyclobalanopsis as a subgenus of Querc