The palynology of the genus Rondeletia L. (Rubiaceae-Cinchonoideae-Rondeletieae)

Pollen of 20 species of Rondeletia, covering three subgenera and seven sections or “species groups” of the genus, was studied using light and scanning microscopy. Rondeletia, characterized by binucleate mature pollen grains like numerous other Rubiaceae, was found to be eurypalynous. The pollen is isopolar and small-sized (average equatorial diameters 11.4–22.8 μm) and 3-colporate (rarely 4-colporate). In equatorial view, the pollen grains are mostly ± spheroidal (rarely suboblate); in polar view (ambitus), they are mainly circular or semiangular (intersemiangular in one species only). Three different exine types are distinguishable: exine with 1) tectum minutely perforate, perforations usually isodiametric, 2) tectum with comparatively large, not isodiametric perforations or 3) coarsely reticulate; supratectal sculpturing elements are lacking; the width of the perforations and lumina is either equal or different at the apo- and mesocolpia; in a few species rod-like luminal processes are present. Palynological features of most of the investigated taxa tend to overlap so that palynology is not very helpful in supporting the subgeneric division of Rondeletia. It was, however, noted that pollen morphology, to some extent, supports the sections of subgen. Arachnothrix. Palynologically, the subgen. Rogiera was found to be heterogeneous in that each of the three investigated species is characterized by a different exine type; one of these, R. strigosa, differs from all other Rondeletia species investigated in having a coarsely reticulate exine. R. odorata (subgen. Rondeletia) differs from all other investigated species in its intersemiangular pollen shape.     

Systematic implications of pollen morphology in Elsholtzia (Elsholtzieae–Lamiaceae)

Pollen morphology of 18 species (32 specimens) representing all three currently recognized sections of the genus Elsholtzia (Elsholtzieae–Lamiaceae) was investigated in detail using light, scanning electron and transmission electron microscopy. Elsholtzia pollen grains are small to medium in size (P=20–50 μm, E=16–45 μm), mostly prolate‐spheroidal to prolate, and rarely oblate‐spheroidal to subprolate in shape (P/E=0.95–1.46), hexacolpate (the amb more or less circular or ellipsoid) with granular aperture membranes. Three distinct types of sexine ornamentation are observed in Elsholtzia: perforate, rugulose‐bireticulate, and bireticulate. The bireticulate pattern is the most common, showing a wide range of morphological variation among species. The exine thickness varies from 1.2 to 2.5 μm. Among the present palynological data, the variability observed in sexine ornamentation of Elsholtzia could be of systematic significance. Current infrageneric classification of the genus Elsholtzia is partially congruent with pollen morphological data.     

Pollen morphology of selected species of Allium (Alliaceae) distributed in Iran

Pollen morphology of 19 species of Allium representing six subgenera and 12 sections, were studied. The following characters were recognized as important for separating taxa at different taxonomic ranks: the sulcus, presence or absence of perforations on the pollen surface, density of perforations, size of perforations and size of the pollen grains. Rugulate, rugulate–striate, and simple–perforate exine ornamentation were distinguished. The type of sulcus is very characteristic in A. subgen. Allium sect. Allium . The extended sulcus was not observed in any species the other sections of subgen. Allium studied here, such as sect. Caerulea ( A. capitellatum ), sect. Codonprasum ( A. lenkoranicum and A. stamineum ) and sect. Avulsea ( A. rubellum and A. umblicatum ). Imperforated pollen grains were observed in representatives of A. subgen. Reticulatobulbosa and subgen. Polyprason .     

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。     

Some evidence for infrageneric classification in Ziziphora L. (Lamiaceae:Mentheae)

The genus Ziziphora L. (Lamiaceae) consists of annual herbs, except Ziziphora clinopodioides, and is represented by six taxa in the flora of Turkey: Z. clinopodioides, Z. capitata, Z. persica, Z. tenuior, Z. taurica subsp. taurica and Z. taurica subsp. cleonioides. They are strong aromatic herbs and important medicinal plants. This study has been conducted to determine the palynological and karyological features of these taxa. The pollen morphology and exine structure of Ziziphora species were investigated by light microscope and scanning electron microscope. Pollen grains were determined as hexacolpate, medium in size and a circular or elliptic amb. The shape of pollen grains varies from oblate to prolate spheroidal. Ornamentation types of pollen grains are bireticulate, microreticulate or perforate. Somatic chromosome number has been determined and counted as 2n = 16, 18. Results indicate that the pollen characters and chromosome numbers of the genus are valuable for taxonomic applications and may be useful for infrageneric classification.     

Phylogenetic relationships in Iranian <Emphasis Type="Italic">Scutellaria</Emphasis> (Lamiaceae) based on nuclear ribosomal ITS and chloroplast <Emphasis Type="Italic">trn</Emphasis>L-F DNA data

The genus Scutellaria (Lamiaceae, Scutellarioidae) includes taxa with a wide range of pharmacological traits, which make this genus economically important. Previous taxonomical studies on Scutellaria were mainly based on morphological and chromosomal characters. The infrageneric classification of the genus has been the subject of a long controversy among authors, and delimitation of taxa remains problematic. In this study, the phylogeny of the genus was evaluated using nrDNA ITS and trnL-F sequences, with a focus on the 42 Iranian taxa belonging to subgenera Apeltanthus and Scutellaria. In both ITS and trnL-F trees, there were two main clades within the genus corresponding to the two subgenera Scutellaria and Apeltanthus. In the subg. Scutellaria, the sect. Anaspis was monophyletic, but the monophyly of sect. Scutellaria was not supported. In this subgenus, S. galericulata was located away from other species in both trees, supported the isolation of this species from the sect. Scutellaria and inclusion in the sect. Galericularia as was previously considered by some authors. In subg. Apeltanthus, sect. Apeltanthus and sect. Lupulinaria were not monophyletic; furthermore, the monophyly of subsect. Lupulinaria was not supported. Based on the results of this study, it can be suggested that the sectional classification of both subgenera Apeltanthus and Scutellaria should be revised.     

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 selected Central European species from subgenera Vignea and Carex (Carex,Cyperaceae) and its relation to taxonomy

This study analysed the taxonomic utility of selected features of pollen grains of 45 Central European species of subgenera Vignea and Carex of the genus Carex. Seven quantitative features were analysed: [length of polar axis (P), length of equatorial axis (E), exine thickness on the pole (Exp), exine thickness on the equator plane (Exe), P/E ratio and the relative thickness of exine (Exp/P and Exe/E ratio)] and outline, shape and exine sculpture. Among the biometrical features, the most important for Carex taxonomy (particularly at the level of subgenus) is the thickness of exine (Exp). Marked differences in the morphological structure of inflorescences at the subgenus level are reflected in the differences of pollen features. Results of our studies clearly show an explicit (and not previously described in the palynological literature) taxonomic division of the genus Carex on the basis of pollen biometrical features into two units corresponding exactly to the subgenera (Vignea and Carex). However, the features of pollen grains analysed did not contribute any essential taxonomic criteria at levels lower than subgenus (e.g. sections). An exception was for C. disticha, where it was observed that the poroid areas occurred in pairs, a new feature for sedges. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 164 , 422–439.     

Pollen morphology and phylogenetic relationships in neotropical Phyllanthus (Euphorbiaceae)

In order to provide new insights into phylogenetic relationships among the neotropical taxa of Phyllanthus , 28 illustrations are provided of the pollen grains of 22 selected species studied from 11 sections of the subgenera represented in the neotropics. Special attention has been given to subgenus Conami because of its variability in pollen morphology: of eight species illustrated, the apertures are diploporate colpi in three species and pores in five species; exine ornamentation is vermiculate in two species and pilate in the other six species. The six species in the neotropical sections Pityrocladus and Microglochidion (subgenus Emblica ) are characterized by prolate grains with an increased number of colpi (4–8). Of particular interest are species in which the pollen exine is clypeate (with exine shields); clypeate pollen grains are illustrated in two species of subgenus Xylophylla and in one species of section Cyclanthera that has unique exine shields with single central pila. The pollen of the one Brazilian phylloclade-bearing species illustrated (in section Choretropsis ) has 3-colporate grains with reticulate exine, typical for subgenus Phyllanthus , and very different from the clypeate grains of the West Indian phylloclade-bearing species in section Xylophylla . This pollen evidence clearly demonstrates homoplasy in the origin of phylloclades in Phyllanthus . Pollen morphological data suggest that the neotropical taxa of Phyllanthus have arisen following colonization from Africa (subgenus Kirganelia ) and Asia (subgenus Emblica ). © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 325–338.     

Lessingianthus (Vernonieae–Asteraceae): generic and infrageneric relationships based on pollen morphology

Pollen morphology of 31 species of Lessingianthus was investigated in order to evaluate the generic and infrageneric relationships of Lessingianthus and related genera. Acetolyzed pollen grains were measured, described and illustrated using light microscopy. Non‐acetolyzed pollen grains were investigated using scanning electron microscopy. Pollen grains of Lessingianthus are isopolar monads, suboblate, oblate spheroidal or prolate spheroidal, lophate (30, 29 and 27 lacunae), with small or large polar area, tricolporate. Pollen grains with 30 lacunae occur in the majority of the species examined, and show three apertural, six abapertural, twelve parapertural, six interapertural and three equatorial lacunae. Pollen grains with 29 lacunae occur in L. desertorum, L. simplex and L. virgulatus and are characterized by three apertural, six abapertural, twelve parapertural, six interapertural and two polar lacunae, and by absence of equatorial lacunae. Pollen grains with 27 lacunae occur in L. adenophyllus and L. durus and are characterized by three apertural, six abapertural, twelve parapertural and six interapertural lacunae, but lack polar and equatorial lacunae. Species of Lessingianthus subgen. Lessingianthus, with few exceptions, have pollen grains with type B lophate pattern, which differs mostly in shape. Pollen grains of Lessingianthus subgenus Oligocephalus share a very similar pattern of 29 lacunae with those of Chrysolaena, supporting recently proposed taxonomic changes. Pollen grains with 27 regular lacunae occur in Lessingianthus durus and L. adenophyllus, but the first differ from the latter by having cross muri enclosing the apertural lacuna (type G pollen).     

Micromorphology of fruits and seeds of Iranian Geranium (Geraniaceae), and its systematic significance

The fruit and seed micromorphology of 22 species of Geranium, representing the eight sections of the genus represented in Iran (G. sectt. Dissecta, Geranium, and Tuberosa of subgen. Geranium; sectt. Batrachioidea, Divaricata, Lucida, Ruberta and Trilopha of subgen. Robertium), have been examined by scanning electron microscopy (SEM). Macro‐ and micromorphological characters, including fruit and seed shape, size, color, hair type and density, mericarp ornamentations, hilum position, seed coat pattern, epidermal cell shape, and anticlinal and periclinal cell walls, are presented. Two microsculpturing patterns are recognized on the mericarp surface: reticulate and pusticulate. The micromorphology of the seed coat showed four distinctive cell patterns. The seed epidermis is constructed either of polygonal, elongated polygonal, or square to rectangular cells. The polygonal type is the most common among the studied species, but the variation in testa cell characters, their size and shape, may provide further information and useful diagnostic characters at specific and infraspecific rank. The shape and color of the seeds are, however, of little systematic value. Fruit characters were found to be important for separating taxa at infrageneric rank and our results show that the species can be separated into subgenera and sections based on fruit morphology.     

New insights into the pollen morphology of the genus Gunnera (Gunneraceae)

Pollen grains from ten species of Gunnera, chosen to represent the six different subgenera in the genus, were examined using light and scanning electron microscopy. The aim of the study was to explore characters that have the potential to define different types of pollen within Gunnera and to study the evolution of these characters in light of the phylogeny of the genus. According to our results, there are three main types of pollen in the examined species of Gunnera. Type 1, unique for the South American species G. herteri (subgenus Ostenigunnera), is characterised by an imperfect reticulum with sinuous undulating-creasted muri. A reticulum with equidimensional polygonal lumina is typical for the plesiomorphic type of pollen (type 2) present in subgenera Gunnera, Misandra and Panke. Lastly, pollen grains of subgenera Pseudogunnera and Milligania are characterised by a reticulum with lumina of variable shape and size (type 3). In G. macrophylla (subgenus Pseudogunnera), the lumina in the apocolpia are of a different shape and size from the lumina in the mesocolpia (type 3a), while in G. dentata, G. monoica and G. cordifolia (subgenus Milligania), the lumina are identical in the apocolpium and the mesocolpium (type 3b).

The identification of pollen types will possibly allow the interpretation of the different specimens of Tricolpites reticulatus, the fossil species believed to be allied to the extant Gunnera.

In addition to the revision on the pollen of Gunnera, a brief comparison between the pollen of this genus and its sister group Myrothamnus is reported.     

Microsporogenesis, microgametogenesis and pollen morphology of Passiflora spp. (Passifloraceae)

Microsporogenesis, microgametogenesis and pollen morphology of six species of genus Passiflora L. belonging to three subgenera ( Passiflora , Dysosmia , Decaloba ) were studied with light and scanning microscopy; P. caerulea was also examined with transmission microscopy. The tapetum is secretory, microspore tetrads are tetrahedral and pollen grains are two-celled when shed. Small Ubisch bodies are attached to a peritapetal membrane; they are a product of tapetal activity and the rough endoplasmic reticulum (ERr) appears to be involved in their origin. The pollen grains of all the species are subspheroidal, zonocolpate, geminicolpate. Each pair of colpi anastomoses at the poles. The exine is semitectate, reticulate, heterobrochate. The muri are simplibaculate, wavy. The lumina have clavate bacula of varying height. The colpus structure is similar to that of the lumina but generally with fewer and smaller bacula. Lumina size and amount of bacula inside the lumina vary between subgenera. The grains from subgenera Passiflora and Dysosmia differ from those of Decaloba in their size and number of colpi. The pollen and microsporangium morphology of the species of subgenera Passiflora and Dysosmia are more similar than those of subgenus Decaloba . The results are discussed in relation to the current taxonomic classification.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society of London , 2002, 139 , 383–394.     

Pollen morphology in the genus Veronica L. (Plantaginaceae) and its systematic significance

Pollen grains of 30, mainly annual, species from 134 populations of the genus Veronica (Plantaginaceae, formerly Scrophulariaceae) from the Mediterranean Region, have been studied with light and scanning electron microscopy. Three pollen types are defined based on pollen size and exine surface sculpture. In some cases within the study group pollen size can be useful in species determination. Hypothetical relationships of pollen grain size and aperture number with ploidy level, style length and corolla diameter are discussed. The ornamentation of the exine in Veronica, although generally a conservative character within the genus, gives some additional support to the most recent infrageneric classification of Veronica.     

Comparative structure of the pollen in species of Passiflora: insights from the pollen wall and cytoplasm contents

Pollen grains of three Brazilian species of Passiflora (P. elegans, P. suberosa and P. haematostigma) belonging to different subgenera were studied with respect to the wall and cytoplasm. New data were obtained on pollen wall histochemistry, cytoplasm contents and organelle inheritance. The structure of the pollen wall layers differed in all the species; P. elegans shares characters with those found in other species from the same subgenus. The exine foot layer is structured and evident only in P. haematostigma and is not structured in P. elegans. The pollen grains have pollenkitt with lipid components. The cytoplasm of the vegetative cell contains dissolved and non-dissolved polysaccharides. The generative cell contains plastids and mitochondria in all the species analyzed, and consequently has the potential for paternal or biparental extranuclear inheritance. Aspects of the evolution of the characters of the species are discussed in the light of a recent phylogeny of the group, with a focus on the three subgenera.     

A Contribution to the Pollen Morphology of Camellia (Theaceae)

The pollen morphology and ultrastructure of 20 species of Camellia (Theaceae) representing the four subgenera were examined. The pollen is tricolporate, spherical to slightly oblate or prolate, with scabrate to rugulate exine sculpturing. The tectum is traversed by perforations that vary in diameter. Pollen wall structure is tectate-columellate, the columellae fused to a footlayer. Endexine is present in all of the taxa examined. The greatest variation was observed in pollen size.     

A palynological study of the genus Nepeta L. (Lamiaceae)

The pollen morphology of forty taxa of the genus Nepeta L. was studied and documented in detail using light microscopy (LM) and scanning electron (SEM) microscopy in this study. Nepeta L. pollen grains are small to large (P = 18.64–63.46 μm, E = 15.62–46.33 μm), suboblate to perprolate (P/E = 0.86–2.09) in shape and hexacolpate (very rarely tetracolpate) with granular membranes. Alternate position of colpi occurs in six Nepeta taxa, N. nuda ssp. glandulifera, N. concolor, N. crinita, N. congesta var. cryptantha, N. stricta var. stricta and N. sibthorpii ssp. tumeniana. In examinations of exine ornamentation with SEM, two types of pollen grains were recognized: (1) type I, with microreticulate sculpture; and (2) type II with bireticulate sculpture, type I and II to be divided into two and five subtypes, respectively. In the two taxa with microreticulate pattern, N. pilinux and N. sulfuriflora, a tendency towards a bireticulum could be recognized due to traces of secondary tectal connections. The bireticulate exine ornamentation is characterized with varying characteristics of the primary muri and secondary reticulum. Pollen morphology within the genus is compared with infrageneric relationships.     

Pollen morphology in the family Asphodelaceae (Asphodeleae,Kniphofieae)

Pollen of 72 species from 7 genera of the Asphodelaceae was studied by means of LM and SEM in order to investigate their taxonomic relationships. The pollen of all the genera investigated is heteropolar, monosulcate, non-operculate and differs in size, form and exine ornamentation. The species of Eremurus are homogenous palynologically and studies of this genus do not support the segregation of the genera Henningia, Selonia, and Ammolirion. The pollen of Bulbinopsis mainly differs from the pollen of Bulbine species in having a perforate-areolate exine surface (B. bulbosa) but the genera are close in their other palynological features. The genera Asphodelus and Asphodeline have the largest, almost spheroidal grains with the thickest exine but differ in details of exine ornamentation. The species of Kniphofia are very close palynologically.     

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.