Pollen morphology of some species of Vernonia s. l. (Vernonieae,Asteraceae) from Argentina and Paraguay

Pollen morphology is widely used in taxonomic treatments of tribe Vernonieae, and differences in exine structure and aperture form have been described for many species within the genera comprising the tribe. However, in recent years a number of new species have been described and, in the present paper, we describe in detail the pollen of 24 species of the tribe which are either endemic or uncommon to certain regions of Argentina or of Paraguay. The pollen of these species are radially symmetrical and more or less spheroidal, 3‐colporate or, in one species, 3‐porate; the exine may be tectate or semitectate and microperforate, with echinate lophae or, in the 3‐porate example, psilate lophae. Using a range of characteristics related to size, shape, wall thickness, apertures and tectum surface morphology, five of the six pollen types previously described for tribe Vernonieae, and a subtype, are recognized. Our results support the usefulness of pollen morphology in helping to determine the taxonomic position of species within tribe Vernonieae.     

Distyly in Polygonum jucundum Meisn. (Polygonaceae)

Pollen grains of tribe Sanguisorbeae (Rosaceae, Rosoideae) were examined using scanning electron microscopy to identify useful characters, test taxonomic and phylogenetic hypotheses among genera, and elucidate pollen character evolution based on a molecular phylogeny. Aperture number, aperture structure, pollen shape, and exine sculpturing were variable within Sanguisorbeae and were used to delineate six pollen types. Four types (I–IV) were observed only in subtribe Sanguisorbinae whereas two types (V–VI) were found only in subtribe Agrimoniinae. Pollen grains of tribe Sanguisorbeae were generally subprolate to spheroidal in shape, had operculate or pontoperculate apertures, and had three apertures, except for Margyricarpus (tetraperturate). Exine sculpturing within Sanguisorbinae represented variations of striate, verrucate, rugulate, and perforate patterns often with microechinate sculpturing. Striate exine patterns and prolate shapes characterized the pollen of the Agrimoniinae, except for the microechinate-verrucate pattern and subprolate to spheroidal shapes observed in Hagenia. Pollen characters are most useful at the generic level and, when mapped on to a molecular phylogenetic tree of the tribe, are concordant with a monophyletic Agrimoniinae and a clade comprising Margyricarpus + Acaena + Polylepis + Cliffortia + Sanguisorba in the Sanguisorbinae. Outgroup comparison indicated that operculate colpi, three apertures, and polymorphism for striate or microverrucate exines represented primitive states for tribe Sanguisorbeae.     

Lophate sculpturing of Vernonieae (Compositae) pollen

Vernonieae (Compositae) taxa Vernonia and Elephantopus were examined by scanning (SEM) and by transmission electron microscopy (TEM). All pollen grains of Vernonia have a subechinolophate sculpturing consisting of a wrinkled net-like ektexine delineating a system of thickened and randomly meandering ridges and corresponding valleys. Ektexine on the ridges radiates from near mid-regions of massive, individual columellae that terminate in sharp spines approximately 4.5 μm above the ektexine surface. Less massive secondary columellae without apical protrusions support the ektexine net in the spine areas. In the valleys, the ektexine is markedly depressed. Removal of the net by freeze-fracture exposes an exine surface that is clearly imprinted with distinctive lophate features. Elephantopus pollen is echinolophate and extends the morphological range for this little studied genus. Lophae are the thickened equivalents of ektexine tecta and represent the highly anastomosing and intertwined rod-like elements of forked distal parts of densely clumped, massive columellae. Lophae surfaces contain rare punctations that are randomly scattered among blunt spinules ranging from approximately 0.3 to 1.5 μm in height. It is clear that only one sculpture pattern, lophate, characterizes Vernonieae pollen and that it embraces two forms, subechinolophate and lophate. Of the two structural patterns in the Compositae, caveate and noncaveate, subechinolophate sculptured Vernonia pollen is noncaveate. Elephantopus pollen is also noncaveate but more generalized than Vernonia.     

中国紫葳科花粉形态的研究

对紫葳科18属27种花粉进行了光镜和扫描电镜的观察,其中有些种是第一次观察或报道。紫葳科花粉明显地属多型花粉,萌发孔类型和纹饰特征多种多样。萌发孔基本上可分为3（－4）沟,3（－4）孔沟,3孔,多沟及散沟等类型;纹饰则可分为皱波状饰,穴状纹饰,穴－网状纹饰,网状纹饰,刺状纹饰以及表面光滑等。值得注意的是在菜豆树属Rademoachera Zoll.et Moritzi中,菜豆树R．sinica和滇菜豆树R.yunnanensis虽为同一个属,但其萌发孔类型和纹饰特征截然不同,菜豆树花粉为3孔,具网状纹饰;而滇菜豆树花粉为3孔沟,具穴状纹饰。就花粉形态学而言,紫葳科也许是多元发生的。     

Pollen morphology of the subtribe Cuspariinae (Rutaceae)

The neotropical subtribe Cuspariinae (Rutaceae) comprises as many as 26 genera and over 125 species. Pollen grains from 111 collections representing 71 species and 24 genera were examined by LM, SEM, and TEM. The pollen morphology of this subtribe is very diverse. Grains are mostly 3–6-aperturate and colporate, rarely porate (Spiranthera) or pantocolporate (Almeidea). Exine sculpturing is most commonly reticulate, sometimes perforate, foveolate-perforate, foveolate, foveolate-reticulate, reticulate, striate-reticulate, echinate, clavate, or baculate. The exine structure is columellate and tectate-perforate, columellate and semitectate, or intectate and is stratified into ektexine and endexine. The exine ofLeptothyrsa is distinctive in that the ektexine of the mesocolpium is longitudinally deeply ridged. The pollen ofHortia, characterized by a psilate exine with rare perforations, a very thick foot-layer, and reduced columellae, is unlike that of any member of the Cuspariinae and offers no support for the transfer of this genus from the Toddalioideae. The pollen data correlate with macromorphological characters and are taxonomically useful.     

蜘蛛抱蛋亚族的花粉形态

本文研究并报道了百合科蜘蛛抱蛋亚族的花粉形态,主要结论如下：1．开口箭属含两种花粉类型即：(1)单槽、椭圆形;(2)无萌发孔、球形。具单槽、椭圆形花粉的种类含单型性核型,花形较小,柱头小而花柱短,雄蕊高于柱头;无萌发孔、球形花粉的种类则为单型性核型,花形较大,柱头常高度膨大,雄蕊常着生在花被筒基部。2．万年青属花粉为椭圆形,具单槽;蜘蛛抱蛋属花粉则为球形,无萌发孔;开口箭属花粉一部分与万年青属相似,另一部分则与蜘蛛抱蛋属雷同。3．蜘蛛抱蛋亚族中最原始的花粉类型为单槽椭圆形,具孔状或网状外壁纹饰。球形,无萌发孔,外壁具皱波状、瘤状或芽孢状纹饰的花粉为派生类型。4．蜘蛛抱蛋亚族种下花粉形状、萌发孔类型和外壁纹饰基本稳定,可作为分种特征。     

Pollen Morphology in the Subtribe Aspidistrinae (Liliaceae s. l.)

Pollen morphology in the subtribe Aspidistrinae is reported and the main viewpoints are summarized as follows: (1) Two major types of pollen grains, i.e., monosulcate,ellipsoidal pollen and inaperturate, spheroidal pollen, are identified in the genus Tupistra. The species with monosulcate, ellipsoidal pollen usually have monomodal karyotypes, brightcolored flower, smaller stigma, and stamens inserted at upper or middle part of perianth tube, while the inaperturate and spheroidal pollen is always found in the species with bimodal karyotypes, dingy-colored flower, swollen stigma and stamens inserted at the base of perianth tube. (2) Pollen grains in the genus Rhodea are monosulcate and ellipsoidal, while those in the genus Aspidistra are inaperturate and spheroidal, correspondingly similar to the second type of pollen grains in the genus Tupistra. (3) The most primitive pollen in the subtribe Aspidistinae is regarded as monosulcate and ellipsoidal, having perforate or reticulate exine sculpture. The inaperturate, spheroidal pollen with verrucate, gemmate or rugulate exine sculpture is considered derived; (4) Unlike those reported in other groups of the family Liliaceae, the infraspecific pollen shape, aperture type and exine sculpture in Aspidistrinae are basically stable and may serve as a taxonomic character.     

Pollen morphology of the tribe Lithospermeae of Boraginoideae in China and its taxonomic significance

The pollen morphology in 15 species representing five genera in the tribe Lithospermeae of Boraginoideae (Boraginaceae) has been investigated and illustrated using light microscopy and scanning electron microscopy. The tribe Lithospermeae is very diverse in pollen morphology. The pollen grains are 10.4–41.8 × 7–33.1 μm in size with subspheroidal, prolate, cocoon, dumbbell, and ovoid shapes. The pollen apertures are of five types: 3-colporate, 3-syncolporate, 4-8-colporate, 4-6-syncolpate, and 6-7-colpate types. The exine ornamentations are generally smooth or rugulose, sparsely echinulate, and rarely rugulate. Based on pollen morphology, we developed a key to identify the genera of the tribe Lithospermeae, compared the pollen apertures among tribes of Boraginoideae, explained the evolutionary trends of the pollen grains, and discussed the taxonomic position of the tribe Lithospermeae. The palynological data suggest pollen of the eurypalynous type and support the proposal that the tribe Lithospermeae is in the primitive position of the subfamily Boraginoideae, and Echium Linn. is in the tribe Lithospermeae rather than in a novel tribe. Our observations have application potential for identification of pollen fossils of the tribe Lithospermeae.     

国产爵床科芦莉花族植物的花粉形态

报道了国产爵床科Acanthaceae芦莉花族Ruellieae芦莉花亚族Ruelliinae 2属7种、假杜鹃亚族Barlerinae 1属3种和马蓝亚族Strobilanthinae 16属34种植物扫描电镜下的花粉形态.芦莉花亚族的地皮消属Pararuellia和喜花草属Eranthemum的花粉均为圆球形,具3孔或3孔沟,外壁为不同的网状结构; 假杜鹃亚族的假杜鹃属Barleria的花粉为长球形,具3孔沟,外壁亦为网状结构;马蓝亚族植物(包含广义的马蓝属Strobilanthes s.l.)花粉形态多样,结构复杂.依据花粉萌发孔和外壁纹饰特征,可将马蓝亚族16属植物和上述两亚族3属植物的花粉形态归纳成3大类型: 1. 具3孔类型.其中又有(1)外壁具网状纹饰者,见于地皮消属; (2)外壁具芽胞状纹饰者,见于黄猄草属Championella; (3)外壁具刺状(棒状)纹饰者,见于南一笼鸡属Paragutzlaffia、叉花草属Diflugossa和假蓝属Pteroptychia.2. 具3孔沟及具3孔沟与假沟类型(肋条带型).其中又有(1)具3孔沟和网状纹饰者,见于喜花草属和假杜鹃属; (2)具刺状(棒状)纹饰者,见于南一笼鸡属、叉花草属和假蓝属; (3)具3孔沟与假沟,外壁纹饰具节隔、肋条带状或网状,网眼纵向排列成行,网眼内有细网纹者,见于耳叶马蓝属Perilepta、马蓝属Pteracanthus(大部分)、金足草属Goldfussia、紫云菜属Strobilanthes(部分)和合页草属Sympagis; (4)具3孔沟与假沟类型,肋条带状,但不具节隔,外壁纹饰网状,网眼不成行或不明显纵向排列,网内无细网纹者,见于尖蕊花属Aechmanthera、板蓝属Baphicacanthus、马蓝属(部分)和糯米香属Semnostachya; (5)具双脊及细网状纹饰者,见于环毛紫云菜Strobilanthes cycla.3. 具(4-)5孔沟及假沟类型(肋条带型),外壁具网状或拟网状纹饰,见于腺背蓝属Adenacanthus.另外兰嵌马蓝属Parachampionella、山一笼鸡属Gutzlaffia和肖笼鸡属Tarphochlamys的花粉有无萌发孔尚不清楚,有待进一步研究.综上所述,芦莉花族植物的花粉形态具有较高的多样性,是重要的分类性状.利用花粉形态特征能较好地区分高级分类群如亚科、族以及亚族,有时也有助于阐明类群之间的相互关系,甚至也能用于区分属、种和阐明其关系.     

Pollen morphology of the Gardenieae-Gardeniinae (Rubiaceae)

Pollen grains of 107 species of 61 genera of the Gardeniinae were investigated by scanning electron and light microscopy. The subtribe is europalynous and grains occur either as monads, tetrads or massulae. Grains are porate, colporate or rarely pororate. The majority of the genera has 3-zonoaperturate pollen grains. However, deviating numbers of apertures occur in Byrsophyllum (4–8) and Pseudomantalania (4–5). Pantoporate pollen occurs in Randia . The average equatorial size (E) of monads varies between 13 μm in Anomanthodiu to 59 μm in Posoqueria . The tetrads vary from 37 μm in Casasia to 61 μm in Calochone and Euclinia . The exine is usually reticulate, but also foveolate, rugulate, perforate and psilate exine occurs in the subtribe. The thickness of the exine is only 0.3 μm in tetrad grains of Randia armata and in the pantoporate monad grains of R. ruiziana , whereas the thickest exine occurs in Posoqueria (2.8 pm) and Euclinia (2.9 μm). Tectal excrescenses are generally absent. However, three genera with pollen in tetrads, namely Euclinia, Gardenia and Oligoco-don , show this feature. Contrary to the subtribe most genera are fairly stenopalynous, but in the neotropical genera Alibertia and Randia several different types of pollen are encountered.     

Palynological evolutionary trends within the tribe Mentheae with special emphasis on subtribe Menthinae (Nepetoideae: Lamiaceae)

The pollen morphology of subtribe Menthinae sensu Harley et al. [In: The families and genera of vascular plants VII. Flowering plants·dicotyledons: Lamiales (except Acanthaceae including Avicenniaceae). Springer, Berlin, pp 167–275, 2004] and two genera of uncertain subtribal affinities (Heterolamium and Melissa) are documented in order to complete our palynological overview of the tribe Mentheae. Menthinae pollen is small to medium in size (13–43 μm), oblate to prolate in shape and mostly hexacolpate (sometimes pentacolpate). Perforate, microreticulate or bireticulate exine ornamentation types were observed. The exine ornamentation of Menthinae is systematically highly informative particularly at generic level. The exine stratification in all taxa studied is characterized by unbranched columellae. Orbicules are consistently absent in Menthinae. Our palynological data are interpreted in a phylogenetic context at tribal level in order to assess the systematic value of pollen characters and to evaluate the existing molecular phylogenies for this group. Pollen morphology suggests Heterolamium as a close relative of subtribe Nepetinae and supports the molecular affinity of Melissa to subtribe Salviinae.     

Pollen morphology of the tribe Ruellieae (Acanthaceae) from

Pollen morphology of seven species in two genera in the Ruelliinae, three species in one genus in the Barlerinae and 34 species in 16 genera in the Strobilanthinae (Ruellieae, Acanthaceae), were observed under SEM. Pollen grains in Ruellieae, particularly in Strobilanthinae (including Strobilanthes s.l.) exhibit great diversity and are most eurypalynous in the family. In light of the aperture types and exine ornamentation patterns, pollen grains of the genera examined fall into three major types: 1. 3-porate pollen, which includes, (1) pollen with reticulate exine ornamentation (Pararuellia); (2) pollen with gemmate exine ornamentation (Championella); (3) pollen with echinate exine ornamentation (Paragutzlaffia, Diflugossa and Pteroptychia). 2. 3-colporate pollen or 3-colporate pollen with pseudocolpi, which includes, (1) 3-colporate pollen with reticulate exine ornamentation (Eranthemum and Barleria); (2) 3-colporate pollen with pseudocolpi and ribbed or banded, and septate exine ornamentation, the lumina rounded, finely reticulate inside and arranged in longitudinal rows (Perilepta, Pteracanthus, Goldfussia, Sympagis and some species of Strobilanthes); (3) 3-colporate pollen with ribbed or banded yet not septate exine ornamentation, the lumina neither distinctly rounded and finely reticulate inside, nor conspicuously arranged in longitudinal rows (Aechmanthera, Baphicacanthus, Semnostachya and some species of Pteracanthus); and (4) 3-colporate pollen with ribbed and finely reticulate exine ornamentation but with broader bands, each band with two ridges (Strobilanthes cycla). 3. (4-)5-colporate pollen with pseudocolpi and reticulate or ornate exine ornamentation (Adenacanthus). No distinct apertures were observed in three genera, Parachampionella, Gutzlaffia and Tarphochlamys. Pollen morphological characters in the Acanthaceae can be used not only to distinguish taxa of higher ranks (subfamily, tribe and subtribe) and elucidate their relationships, but sometimes can also be used to distinguish genera and species.     

Pollen morphology of the tribe Rhinantheae (Orobanchaceae) and its systematic significances

Pollen morphology of 36 species representing 14 genera within the tribe Rhinantheae in the family Orobanchaceae was studied and illustrated with light microscopy (LM) and scanning electron microscopy (SEM). Five major pollen types were recognized on the basis of exine ornamentation. Within these major types, minor types (subtypes) were distinguished based on exine surface pattern, size, shape, amb form, colpi and colpus membrane. These types and subtypes are as follows: type I. retipilate: subtype Ia. regular retipilate: (1) pollen size < 27 μm, (2) pollen size > 27 μm, subtype Ib. irregular retipilate; type II. verrucate: subtype IIa. macro-verrucate, subtype IIb. verrucate, subtype IIc. sparse verrucate; type III. retirugulate; type IV. granulate; type V. micro-reticulate. A key to pollen morphology of genera studied within the Rhinantheae was made based on pollen morphology from our study and earlier work. Combining with other sources of information on the Rhinantheae, the systematic relationships of this tribe are discussed. Rhinantheae pollen displays considerable variation between genera and species, with taxonomically significant characters at genus and species level. Palynological characteristics provide evidence for interpreting the conflicting views concerning the “Pterygiella Complex”. The evolutionary trend in exine sculpture of Rhinantheae could be proposed, namely that retipilate sculpturing which is the most widespread type is more primitive than the other types (such as foveolate, granulate, regulate, reticulate, retirugulate and verrucate). The pollen data in present study and the view of Hong (1986), as well as the molecular data from Bennett and Mathews (2006) indicated that Asia and related regions were likely to the origin centre of the tribe Rhinantheae.     

Systematic importance of pollen morphological features of selected species from the genus Rosa (Rosaceae)

The aim of this study is verification of the taxonomic usefulness of the pollen grain features studied, based on pollen morphology of 32 wild species from all 4 subgenera and all 10 sections of the genus Rosa, mainly for delimitation of subgenera, sections, and species. The measurements and observations were carried out with both light microscopy and scanning electron microscopy. Only correctly formed pollen grains (30 per specimen) were measured, and 960 pollen grains were examined in total. They were analyzed for 14 quantitative features of pollen grains and exine sculpturing and the following qualitative ones: outline, shape, and operculum structure. Our study revealed that the diagnostic features of pollen grains studied were: exine sculpture, length of polar axis, and pollen shape (P/E ratio). On the basis of the above characters, five species were isolated and the remaining ones were included in several groups isolated on the basis of exine sculpture types. The following three exine sculpture types occurred in the species studied: granular-verrucate (in R.?stellata), striate-psilate (in R.?multibracteata and R.?multiflora), and striate (the remaining species). R.?banksiae is characterized by small pollen grains, while R.?setigera has strongly elongated pollen with P/E ratio >1.5. Exine sculpture features considered to be diagnostic should be treated as auxiliary because they fail to differentiate individual species, although they can be helpful in distinguishing groups of species of similar exine sculpture. The arrangement of the species examined on a dendrogram only slightly corroborates division of the Rosa genus into subgenera and sections currently adopted in taxonomy (Rehder 1940). An interesting result was reported for the species studied from the Caninae (R.?agrestis, R.?canina, R.?dumalis, R.?jundzillii, and R.?rubiginosa) section which, despite hybrid nature, with the exception of R.?villosa, grouped in the same, most separated group of species.     

部分中国传统月季花粉形态研究

利用扫描电镜观察了15个中国传统月季品种的花粉形态。结果表明:传统月季花粉为单粒花粉,呈长球形或超长球形（P/E为1.92～2.25）,大小为37.59～51.95 μm×17.02～25.33 μm。赤道面观椭圆形或长矩形,极面观三裂圆形,具三孔沟,沿极轴方向等间距环状分布。外壁纹饰条纹型,覆盖层具穿孔,在品种间具有相似性,但变异丰富,划分为4种类型。聚类分析结果表明,花粉大小和外壁纹饰特征在反映传统月季品种的类别上与形态分类基本一致。根据花粉形态演变规律可推断,样品中‘四面镜’可能为最原始的品种类型,‘月月粉’、‘月月红’及‘匍匐红’等品种较为进化。     

Taxonomic significance of pollen types in the Guyana Highland-centred composite genera of Mutisioideae (Asteraceae)

The Guyana Highland-centred genera, or Stenopadus group, are a complex of species that belong to the tribes Mutisieae and Stifftieae of Asteraceae. The pollen morphologies of 29 species, from 12 of 13 genera of this complex, are described and illustrated using light and scanning electron microscopy. The exine sculpture and structure are highly significant. Four exine types, previously characterized, were distinguished: Gongylolepis , Wunderlichia , Mutisia , and Stenopadus . The characterization of the Stenopadus exine type is enlarged here. These exine types led to the recognition of four well-defined pollen types, whereas the spine length and exine thickness characterized six subtypes. Pollen types circumscribe genera or groups of genera, and some subtypes distinguish species. The pollen morphology within the complex is discussed in relation to the rest of Mutisioideae and other palynologically allied tribes of Cichorioideae. There is little correlation between pollen types and tribes; only the Stenopadus exine type is exclusive to the Stifftieae tribe. The remaining types are shared by the two tribes of the complex. Pollen morphology supports the hypothesis that this group of genera is close to the Gochnatia complex and the Cardueae tribe.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 327–340.     

Pollen morphology of some selected plant species from Horton Plains,Sri Lanka

The pollen morphology of four species: Gaultheria leschenaultii (Ericaceae), Psychotria zeylanica (Rubiaceae), Rubus leucocarpus (Rosaceae) and Symplocos bractealis (Symplocaceae) from Horton Plains, Sri Lanka was investigated using LM and SEM. Psychotria zeylanica is endemic to Sri Lanka and the other three taxa are common in Horton Plains. Gaultheria leschenaultii has tetrads with 3-colporate, coarsely granular to granulo-rugulate pollen grains; in the polar region and at the colpus margin the exine is smooth with micro-rugulate structure. Psychotria zeylanica has 3- (or 4-) colporate, reticulate-spinulose to granular pollen grains. Rubus leucocarpus has 3-colporate, striate-perforate pollen grains and Symplocos bractealis has 3- (or 4-) colporate pollen grains with a verrucate-perforate exine. Pollen grains of these four species are very indicative of human impact and palaeoclimate.     

POLLEN MORPHOLOGY AND DETAILED STRUCTURE OF FAMILY COMPOSITAE,TRIBE CICHORIEAE. I. SUBTRIBE STEPHANOMERIINAE

A survey of pollen morphology in 20 species representing the 11 genera of the North American subtribe Stephanomeriinae by light, scanning electron, and transmission electron microscopy revealed 10 of the 11 genera to have echinate, tricolporate pollen grains, Lygodesmia being the only genus with echinolophate pollen. Sectioned exines of most of the species examined are similar, being composed of ektexine and endexine. The ektexine surface is composed of spines which typically have globose perforate bases. A cavus occurs as a separation between the basis (foot layer) and the columellae in all of the genera examined except Chaetadelpha. Pollen of the two species of Glyptopleura were found to be strikingly different in exomorphology. Pollen of the putatively self-fertile G. marginata has much shorter spines than the closely related G. setulosa. Atrichoseris, Anisocoma, Calycoseris, Glyptopleura, Pinaropappus, Prenanthella, and most species of Malacothrix have pollen which lack paraporal ridges. The remaining genera, Chaetadelpha, Lygodesmia, Rafinesquia, and Stephanomeria have well-developed ridges of fused spine bases around the apertures. Pollen characters, particularly those of the aperture region, have been found to be systematically useful in the subtribe, therefore acetolyzed material gives more useful information than untreated pollen.