Pollen morphology of Chinese Glochidion (Phyllanthaceae) and its taxonomic implications

The pollen morphology of twenty‐five Chinese species belonging to two sections of Glochidion and one species from Phyllanthus subgen. Phyllanthodendron was examined using scanning electron microscopy (SEM). The results showed that pollen grains of Glochidion are isopolar, spheroidal to rarely subprolate in shape, (3)4–5(6)‐colporate in aperture pattern, and tectate‐reticulate to tectate‐rugulate in exine ornamentation. Fusion of colpus ends was observed in some pollen grains of G. pseudo‐obscurum and G. wrightii. The pollen grains of Phyllanthus dunnianus are similar to those of Glochidion species in their spheroidal shape and four‐colporate aperture pattern, but are slightly larger in size, and show tectate‐perforate exine ornamentation. In Glochidion, pollen morphology appears to be useful for distinguishing several macromorphologically similar. Additionally, palynological characters provide evidence for the taxonomy of the supergenus Phyllanthus s.l.     

Pollen morphology of Euchaetis and Macrostylis (Diosminae-Rutaceae) and its taxonomic implications

Pollen morphology of Euchaetis and Macrostylis , both members of the taxonomically problematic subtribe Diosminae (Rutaceae), was investigated by LM, SEM and TEM. Here we report on the taxonomic significance of pollen morphology based on a comparative study of 28 infrageneric taxa. Three pollen types were found, namely reticulate (common to both genera), perforate (in Euchaetis ) and striato-reticulate (in Macrostylis ). Pollen data provide evidence of relationships between the two genera as well as with other genera, and further support for the macromorphological evidence suggesting the generic re-classification of the Diosminae.     

Pollen morphology and taxonomic implications of Muscari Miller (Hyacinthaceae) species from Sicily

Pollen morphology of the native Sicilian species of the genus Muscari, one of which is endemic to Sicily, belonging to the subgenera Muscari, Leopoldia and Pseudomuscari, was studied using a light microscope and a scanning electron microscope. Pollen grains are monads, heteropolar and monosulcate; the exine is semitectate reticulate and perforate. The sulcus extends from distal to proximal face and its length is not directly proportional to the size of the granules and varies from one species to another.     

Pollen morphology of Adenandra (Rutaceae: Diosminae) and its taxonomic implications

The pollen morphology of Adenandra Willd. (Rutaceae: Diosminae) was investigated to determine its taxonomic significance. Pollen of 27 of the 30 infrageneric taxa (representing 16 of the 18 species) was investigated by LM, SEM and TEM. Adenandra differs from all other Diosminae in having 4-colporate rather than 3-colporate pollen grains. This supports the alleged monophyletic status of the genus. Exine morphology and structure, however, is extremely diverse considering the size of the genus, with eight distinct pollen types and four subtypes being discerned. In some members the grains have uniform macroreticulate, striate or striato-reticulate sculpturing, whereas in others the poles have striate, striato-reticulate or reticulate-perforate sculpturing with various types of reticulate or rugulate sculpturing at the mesocolpia. Taxonomic groupings revealed by the pollen characters suggest elationships between taxa that were not previously apparent. It is suggested that evolutionary diversification among species of Adenandra is often more strikingly reflected by pollen morphology than by macromorphology, hence the eurypalynous state of the genus.     

Pollen morphology of Strobilanthes Blume (Acanthaceae) in China and its taxonomic implications

The pollen morphology of 37 Chinese species of Strobilanthes Blume (Acanthaceae), a large and taxonomically problematic genus, was investigated by LM and SEM. Two distinct pollen shape classes, ellipsoid and spheroidal, recognised by earlier workers were found. Eight pollen types could be distinguished on the basis of variation in ornamentation, and the number, distribution and type of apertures. Five of these fall within twenty two pollen types reported from Strobilanthes in southern India and Sri Lanka. Three new pollen types are also described, further extending the palynological diversity of the genus. From the results presented, the characters of palynological diversity and the related taxonomic implications are discussed.     

Pollen morphology in Primula sect. Carolinella (Primulaceae) and its taxonomic implications

Pollen morphology in Primula section Carolinella has been investigated for the first time. Seven of the nine species constituting the section were available for study, i. e., P. cardioeides, P. chapaensis, P. intanoensis, P. kwangtungensis, P. kweichouensis, P. partschiana , and P. rugosa, A considerable variation in pollen morphology was found among the investigated species, particularly in number and arrangement of the apertures. Pollen of different species were either tricolpate, tricolporate, trisyncolpate, or polycolpate. Within Primula , the section Carolinella is diagnosed by having calyptrate capsules and leaves with revolute vernation, but the variation in pollen morphology indicates that this group is heterogeneous, and that either polycolpate pollen or a capsular lid has evolved more than once in the genus Primula.     

Pollen morphology of Phyllosma and Sheilanthera (Diosminae: Rutaceae) and its taxonomic implications

Phyllosma (two species) and Sheilanthera (one species) are members of the taxonomically problematic subtribe Diosminae, Rutaceae. Pollen morphology of all three species was investigated by LM, SEM and TEM to shed light on their relationships to other genera of the subtribe. Sheilanthera shares pollen morphological features with many other species in the subtribe, but the pollen of Phyllosma is distinctive. Possible relationships between Sheilanthera and Acmadenia, and between Phyllosma and Agathosma are suggested. The macromorphological characters of the species correspond to the pollen morphology.     

Pollen morphology of Diosma and Coleonema (Rutaceae: Diosminae) and its taxonomic implications

The pollen morphology of Diosma and Coleonema of the taxonomically problematic subtribe Diosminae (Rutaceae) was investigated to determine its taxonomic relevance. Pollen of 26 of the 28 species of Diosma and of each of the eight species of Coleonema was investigated by LM, SEM and TEM. In pollen of Diosma the exine sculpturing is uniform, and only one pollen type, reticulate, could be distinguished. In contrast, exine sculpturing shows interspecific variation in Coleonema and three distinct types, striate, reticulate and perforate, could be discerned. Species groupings indicated by the pollen types suggest possible relationships between species within Coleonema and with other genera that were not previously apparent. Pollen data support macromorphological evidence that suggests the generic re-classification of the Diosminae.     

Pollen morphology of six species of Bupleurum L. (Apiaceae) present in Sicily and taxonomic implications

Abstract

In this study, using light and scanning microscopes, the morphobiometric characters of pollen grains of Bupleurum fruticosum L., B. fontanesii Guss. ex Caruel, B. gerardi All., B. lancifolium Hornem., B. semicompositum L., B. tenuissimum L. have been analysed. The elaboration of qualitative and quantitative palynological data has allowed us to formulate a key of identification which characterizes six morphotypes. Pollen grains of B. fruticosum (a perennial species) have been distinguished from the grains of the other annual species examined by us on the basis of several morphobiometric characters, a condition which has confirmed the systematic arrangements suggested by several authors. The close palynological affinity between B. tenuissimum and B. semicompositum compared with B. gerardi has supported the placement of these three species in a distinct subsect. of the sect. Eubupleura Briq. or in a distinct subsect. of the sect. Isophyllum (Hoffm.) Dumort. Similarly, our palynological data on B. fontanesii have confirmed the systematic arrangement. However, these data differ from those reported by different authors who placed the three species in the sect. Aristata Godron subsect. Juncea Briq.     

Pollen morphology and its taxonomic significance of the monotropoideae (Ericaceae)

A palynological survey, including LM, SEM and TEM is presented for eight genera, nine species and 76 samples of the Monotropoideae which is composed of 10 genera and 13 species. On the basis of the aperture number and shape, the following six pollen types are recognized: 1) 3-colp(oroid) ate—Allotropa, 2) 2-colpor(oid)ate—Monotropsis andHemitomes, 3) 4-colpor(oid)ate—Pterospora, Sarcodes andPleuricospora, 4) 2- and 3-colpor(oid)ate—Monotropa hypopitys, 5) 3-colporate and-porate —Monotropa uniflora, 6) 3- to 4- porate—Monotropastrum humile. Relationships among taxa within the Monotropoideae are illustrated on the palynological characters including the aperture type, exine sculpture and structure. Both pollen grains with two and four apertures have evolved independently from pollen grains with three apertures, according to the infraspecific variation of aperture numbers and the usual occurrence of three-aperturate pollen grains in the Ericaceae. 3-colp(oroid)ate pollen ofAllotropa is the most primitive and occupies an isolated position in the subfamily, on the other hand 3- to 4-porate pollen ofMonotropastrum humile is most advanced in the subfamily, probably even in the Ericaceae. A reduced sexine inMonotropastrum humile appears to be a specialized pollen character. Infraspecific geographical difference in palynological characters is revealed in two species ofMonotropa for the first time.M. hypopitys is basically characterized by pollen grains with two apertures in the New World vs. three apertures in the Old World.M. uniflora is basically characterized by 3-porate pollen in the New World vs. 3-colporate in the Old World. In both species pollen grains with more primitive characters usually occur in the Old World.     

Seedling morphology of three mangrove species and its taxonomic implications

Seedling establishment is an important part of the life cycle of mangroves. Very early in the juvenile stage, they face adverse situations such as a variable and unstable substrate as well as a high-saline environment Therefore, the propagules should have some ability to float in saline water. Seedlings differ morphologically from the adult plants. Here, I examined the seedling growth stages in three species of mangrove:Aegialitis rotundifolia Roxb.,Aegiceras corniculatum (L) Blanco, andAvicennia marina (Forsk.) Vierh. that grow in the Sundarbans swamps of West Bengal. In all cases, fruits were the propagating units; seeds were inseparable from those fruits. Germination was rapid and required no dormancy period. The hypocotyi pierced the seed coat rather than emerging from the pericarp — a variation on the traditional viviparous type of germination. Seedlings then became exposed prior to abscission from parent plants. Based on germination patterns and differences in seedling morphology observed here, these species should be classified in a more relevant taxonomic group than was done previously.     

Pollen morphology ofPyrola and its taxonomic significance

Pollen from 152 collections representing 16Pyrola species was examined with LM, SEM and TEM. The genusPyrola is stenopalynous in having tetrads and 3-colporoidate grains. However, a continuous and serial variation in the exine sculpture and the tetrad diameter (D) was revealed within the genus. Křísa's system ofPyrola (1971) was re-examined in the light of these palynological characters which may have a taxonomic significance, as well as the external morphology. P. minor (only member of the subgenusAmelia), which is characterized by having small (D=30–35 μm) pollen tetrads with verrucate sculpture must best be placed near sectionPyrola of the subgenusPyrola. P. faurieana must be segregated from sectionChlorantha and together withP. media placed intermediate between the subgenusAmelia and sectionPyrola of the subgenusPyrola based on their larger (D=ca. 40 μm) pollen tetrads with verrucate sculpture. Two series of sectionChlorantha excludingP. faurieana are differentiated in the exine sculpture. Therefore, they are regarded as the distinct taxonomic groups. SectionScotophylla is characterized by having psilate sculptured pollen tetrads, which indicates that its sectional rank is sufficiently asserted. The evolutionary trend in the exine sculpture from verrucate through rugulate to psilate is suggested withinPyrola.     

杜鹃花属植物花粉形态及其分类学意义

利用扫描电子显微镜对5个亚属20种杜鹃花属植物的花粉形态进行了观察和比较研究,其中大部分(16种)为首次报道。杜鹃花属花粉均为四合花粉,呈正四面体排列。四合体为圆角三角形,连接紧密。单粒花粉为球形或近球形,具三沟孔。在扫描电镜下,除了杜鹃亚属的百合杜鹃、羊踯躅亚属的羊踯躅以及马银花亚属的马银花组具有明显的纹饰特征之外,其它类群的形态特征相互重叠,不足以作为现有亚属的分类依据。花粉粒具不同的外壁纹饰,可为分类研究提供孢粉学方面的证据,但应慎重应用花粉形态对杜鹃花属植物特定种进行分类鉴定。     

Pollen morphology in the genus Coffea (Rubiaceae) and its taxonomic significance

The pollen morphology of 38 representative species and varieties within the genus Coffea L. is described. Eight pollen types, placed in two major groups, have been identified on the basis of the number of colpi, colpus characteristics, exine morphology and pollen size. Differences in pollen structures of the species studied do not correspond to present taxonomic groupings, but support a current proposal to place some of the species in the genus Paracoffea Leroy. Among the four sections in the genus, the section Eucoffea contains a high degree of pollen polymorphism.     

Pollen morphology of the Pavetteae (Rubiaceae,Ixoroideae) and its taxonomic significance

Pollen grains of the tribe Pavetteae (Rubiaceae, subfamily Ixoroideae) are examined using LM and SEM. Grains are 3‐ or 4‐colporate and (semi‐) tectate (in one Versteegia species atectate). Sexine patterns vary between perforate, microreticulate, reticulate, rugulate and striato‐reticulate. Supratectal elements are sometimes present. The variation in pollen morphology in the Pavetteae allows to recognize seven pollen types, the distribution of which is useful to evaluate generic delimitations and relationships within the tribe. Pollen characters corroborate the close relationships between the genera Coleactina, Dictyandra and Leptactina and between Homollea, Homolliella and Paracephaelis. All the genera of the tribe proved to be stenopalynous (the species examined possess the same pollen type), except Pavetta, Rutidea, Versteegia and Tarenna which are eurypalynous. In the huge genus Pavetta the existing infrageneric classification is supported pollen morphologically. Pollen morphology further indicates that the genus Tarenna is badly delimited and strongly in need of a revision. The small genus Versteegia is in need of further taxonomic and palynological study to understand the pollen morphological variation encountered here. At a higher rank, pollen morphology also does not contradict the recent division of the Pavetteae in the Ixoreae (a stenopalynous tribe with presumably primitive pollen) and the Pavetteae sensu stricto (eurypalynous).     

中国算盘子属(叶下珠科)果实形态特征及其分类学意义

算盘子属是一个分类较为困难的大类群,全世界超过300种,其中众多物种间的界定至今颇存争议。本研究在野外考察及对馆藏标本查阅的基础上,对中国算盘子属21种1变种的果实形态进行了仔细观察和研究。结果显示,该属物种果实被毛情况、果实大小、宿存花柱、纵沟深浅和数目等形态特征在种间具有很高的多样性,可用于对不同物种的鉴别,具有一定的分类学价值。基于果实形态特征提供了这21种1变种的分类检索表。