Spore morphology of the north Asian members of Cystopteridaceae

Spores of Cystopteridaceae from northern Asia were examined using scanning electron microscopy. To evaluate the utility of spore morphology in the taxonomy of each genus, we examined spores of 14 species: seven species each of Gymnocarpium and Cystopteris. Among these are 12 species occurring in northern Asia and two species from other regions for comparative studies. The study focused particularly on perispore characters and spore size. Spores of all species examined are monolete, bean-shaped, with a range in spore size of 26–56 × 18–37 μm for Cystopteris and 25–48 × 16–34 μm for Gymnocarpium. The perispore is morphologically diverse within Cystopteris, but less so within Gymnocarpium. The perispore of the Cystopteris spores is characterised by folds and spines that are separate or form complex sculptural elements. Sacci, ridges and flanges, sometimes on the same spore, are characteristic of the perispore of Gymnocarpium. Spores have straight laesura over which the perispore forms a crest. The crest represents a high and flat fold, which is entire, foveolate or reticulate.     

Spore wall ultrastructure in Anogramma species (Pteridaceae) from Argentina

The sporoderm ultrastructure of Anogramma Link species, which grow in Argentina, was studied using scanning and transmission electron microscopy. The species A. chaerophylla (Desv.) Link and A. lorentzii (Hieron.) Diels were studied with TEM for the first time. The spores of both species have a sculptured, apparently two-layered exospore. The perispore is uniformly thickened on the whole surface: in A. chaerophylla it is three-layered, while, in A. lorentzii it is single-layered with a complex structure. Spherules are present on the perispore surface or incorporated into the structure of A. chaerophylla while, globules exist on and within the perispore in A. lorentzii. The sporoderm ultrastructure in these two species was compared with other cingulate genera within the Pteridaceae. The characteristics found in this work, with respect to spore wall structure and general morphology, suggest that these characters may differentiate species within genus.     

ULTRASTRUCTURAL STUDY ON SPORE WALL MORPHOGENESIS IN LYCOPODIUM CLAVATUM (LYCOPODIACEAE)

Spore wall morphogenesis of Lycopodium clavatum was observed by transmission electron microscopy. The spore plasma membrane indicates the reticulate spore sculpture shortly after meiosis. The mature spore wall of this species consists of two layers, inner endospore and outer exospore. There is no perispore in the sporoderm of this species. The exospore formation begins during the tetrad stage; and this layer is divided into two distinct sublayers, an outer lamellar layer and an inner granular layer. The lamellar layer is formed on the sculptured spore plasma membrane. Additional lamellae attach to this layer in a centripetal direction. For that reason, this layer may be derived from spore cytoplasm. The granular layer is formed only in the proximal region following lamellar layer formation, and it also may be derived from spore cytoplasm. The endospore is formed lastly and seems to be derived from spore cytoplasm as well. Accordingly, the spore sculpture of this species may be under the genetic control of the spore nucleus.     

COMPARATIVE LEAF STRUCTURE OF SEVERAL SPECIES OF HOMOSPOROUS LEPTOSPORANGIATE FERNS

The structure of the mature leaves of 13 species from 9 families of homosporous leptosporangiate ferns was examined by light and electron microscopy. In 11 species (Adiantum pedatum L., Athyrium angustum Roth., Cyathea dregei Sm., Lygodium palmatum Sw., Mohria caffrorum (L.) Desv., Oleandra distenta Kuntae, Pellaea calomelanos (Sw.) Link, Pityrogramma calomelanos (L.) Link var. austro-americana (Domn.) Farw., Trichomanes melanotrichum Schlechtend., Vittaria guineensis Desv., and Woodwardia orientalis Sw.) the lamina veins are collateral; in two (Phlebodium aureum and Platycerium bifurcatum), bicollateral as well as collateral veins are present. The vascular bundles in the midribs of C. dregei and those in the petioles and midribs of Phlebodium and Platycerium are concentric. All of the vascular bundles in the homosporous leptosporangiate ferns studied are delimited by a tightly arranged cylinder of endodermal cells with Casparian strips. Within the veins without parenchymatic xylem sheaths, some sieve elements commonly abut tracheary elements with hydrolyzed primary walls. The majority of vascular parenchyma cells contact both sieve elements and tracheary elements, although some parenchyma cells are associated with only one type of conducting cell. Transfer cells (parenchyma cells with wall ingrowths) occur in the veins of 6 species examined. Most of the vascular parenchyma cells, however, have no distinctive structural characteristics. The sieve elements of the homosporous leptosporangiate ferns are very similar structurally and each consists of a plasmalemma, a parietal, anastomosing network of smooth endoplasmic reticulum (ER), and variable numbers of refractive spherules, plastids and mitochondria. The sieve elements of L. palmatum also contain plasmalemma tubules. The parenchymatic cells of the leaf (mesophyll, endodermal and vascular parenchyma cells) are united by desmotubule-containing plasmodesmata. The sieve elements are connected to each other by sieve pores and to parenchymatic cells by pore-plasmodesma connections. The sieve-area pores contain variable amounts of membranous material, apparently ER membranes, but do not occlude them. These membranes commonly are found in continuity with the parietal ER of the lumen. Based upon the relative frequencies of cytoplasmic connections between cell types, the photosynthates may move from the mesophyll to the site of phloem loading via somewhat different pathways in different species of homosporous leptosporangiate ferns.     

Spore morphology and ultrastructure of Cyathea (Cyatheaceae,Pteridophyta) species from southern South America

Spore sculpture and wall structure of eight Cyathea (Cyatheaceae) species from southern South America were studied using light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. Two layers, i.e. an inner and an outer layer, were observed in the perispore. The inner layer has two strata: the inner stratum is attached to the exospore and composed of rodlets tangentially oriented to the spore surface and randomly intermixed; the outer stratum consists of a three-dimensional network of rodlets with either free or fused distal edges forming spinules. The outer layer is thin, darkly contrasted and covers the rodlets. In most cases, the exospore has two layers and a pitted surface. In Cyathea atrovirens, the exospore surface is smooth, while in C. delgadii and C. myriotricha it is verrucate. The homogeneity of perispore features within the genus Cyathea is evident, while exospore features are heterogeneous. The exospore has different kinds of surface-structures that are of potential interest for assessing evolutionary trends within the group.     

Morphological studies on the nutlet of Turkish Cyclotrichium Manden. & Scheng. (Lamiaceae)

Morphological characters of the nutlets of Cyclotrichium Manden. & Scheng. in Turkey were examined using scanning electron microscopy (SEM). The genus Cyclotrichium is represented by six species in Turkey, of which two are endemic for Turkey. Nutlet morphology of the species was studied using stereoscopic microscopy and SEM, and the features were described and illustrated. Nutlet morphology of the examined specimens exhibits some variation in size, shape and sculpture. Nutlets range from 1.1 to 2.0 mm in length and 0.5 to 1.0 mm in width and are elliptic, oblong to ovoid and trigonous in shape. Nutlet sculpture can be divided into two main types: distinctly or weakly reticulate pattern in C. niveum, C. origanifolium, C. longiflorum and rounded cell arrangement in the remaining species. Micromorphological characters could be useful in solving taxonomic problems of Cyclotrichium.     

Spore morphology and wall ultrastructure of Trachypteris species (Pteridaceae)

Trachypteris is a small genus consisting of four species native to America and Madagascar: Trachypteris induta, T.?pinnata, T.?gilliana, and T.?drakeana. The spores of the genus were studied using light microscopy and scanning and transmission electron microscopy. They are trilete, triangular to globose, with equatorial diameter of 29?C58???m and polar diameter of 26?C53???m. The exospore is 0.5?C1.1???m thick, plane, and two-layered. The perispore is 0.3?C6.8???m thick and two-layered. Depending on the species, two different ornamentations were observed: cristated with partially fused cristae, and ridged with partially fused ridges, forming an incomplete reticulum. Globules immersed in the perispore were occasionally observed. The systematic value of the Trachypteris spores is discussed, and their morphology and ultrastructure are compared with those of other related cheilanthoid ferns. The palynological characteristics presented here may be useful for phylogenetic studies within the Pteridaceae, and particularly within the cheilanthoid ferns.     

POLLEN MORPHOLOGY IN THE GENUS ERYTHRONIUM (LILIACEAE) AND ITS SYSTEMATIC IMPLICATIONS

Pollen morphology was examined in 40 samples from 19 species in the genus Erythronium (Liliaceae) using scanning (SEM) and transmission electron microscopy (TEM). Pollen grains are monosulcate monads, except for a plant of E. oregonum which has dyad grains. North American and European species are characterized by reticulate exine sculpture composed of various degrees of wavy muri and variably-sized lumina. The most distinctive feature of exine sculpture in the genus is exhibited by the Asian species E. japonicum, which has a unique reticulate pattern composed of striate muri and a distinctive exine structure without columellae. The distinctness of E. japonicum pollen suggests that it has specialized in isolation from species in North America and Europe.     

Peregrinipollis Nigericus,A New Palynomorph from the Upper Tertiary of Nigeria

Peregrinipollis nigericus gen. et sp. nov., a tricolpate palynomorph with reticulate and granulate-verrucose sculpture, is described from Upper Tertiary sediments of Nigeria.     

Pollen morphology inParis and its related genera

Pollen grains ofParis, Medeola, andScoliopus have been examined with light, scanning electron, and transmission electron microscopies.P. quadrifolia L.,P. verticillata Bieb.,P. delavayi Franch. andP. polyphylla Smith have monosulcate pollen characterized by psilate, foveolate or reticulate exine sculpture. In contrast to the former species,P. japonica (Fr. et Sav.) Franch. andP. tetraphylla A. Gray have monosulcate pollen with gemmate (rarely rugulate) exine.Medeola has monosulcate pollen with reticulate exine that is distinct from that ofParis. Scoliopus has monosulcate pollen characterized by a peculiar reticulate exine pattern. The palynological evidence suggests thatParis andTrillium are closely related to each other, andMedeola andScoliopus should be separated fromParis andTrillium.     

Pollen Morphology of Parnassia L. （Parnassiaceae） and Its Systematic Implications

The pollen morphology of 28 species of Parnassia L. was investigated with light microscopy and scanning electron microscopy (SEM). The shape of pollen grains in this genus varies from subspheroidal to prolate in equatorial view and is three-lobed circular in the polar view. Pollen grains are usually radially symmetrical, isopolar, tricolporate or syntricolporate, with reticulate sculpture. The pollen characteristics among species are fairly similar to each other. Morphological information regarding the pollen grains shows that Parnassia is a natural genus. Based on exine ornamentation observed under SEM, three types of pollen grains were recognized: (i) type I, with foveolate-reticulate sculpture; (ii) type II, with a finely reticulate sculpture; and (iii) type III, with a coarsely reticulate sculpture. Most sections of this genus have one type of sculpture of pollen morphology, but Sect. Nectarotrilobos has three types of sculpture and Sect.Saxifragastrum has two types of sculpture. All three types of sculpture can be found in Southwest China,with species with the longest (Parnassia delavayi Franch.) and shortest (Parnassiafaberi Oliv.) colpi,implying that Southwest China is the center of diversification of the genus.     

SEED-COAT MORPHOLOGY AND ANATOMY IN COLLOMIA (POLEMONIACEAE)

Seed-coat morphology of 14 species of Collomia (Polemoniaceae) was examined with light microscopy and scanning electron microscopy. Two seed types were observed based on surface sulpturing: Type 1—hexagonal epidermal cells forming a shallow reticulum with well-defined cell boundaries; Type 2—longitudinally ridged and irregularly arranged crater-like depressions with inconspicuous cell boundaries. Only two species, C. debilis and C. larsenii of sect. Collomiastrum have seed-coat Type 1. Seed-coat Type 2 is characteristic of all species of sect. Collomia, sect. Courtoisia, and C. mazama, C. rawsoniana of sect. Collomiastrum. The present investigation reveals a fairly homogeneous seed-coat pattern in the genus and does not offer significant information for realignment of infrageneric classification. Anatomical studies with light microscopy show that a mucilaginous seed coat develops from the outermost layer of integument in which each epidermal cell develops spiral secondary wall thickenings. Mucilaginous seeds of most Collomia species probably provide adaptive significance in that adherence of seeds to ground prohibits further dispersal to unfavorable habitats, or epizoochoric dispersal.     

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.     

山东水龙骨科植物孢粉学研究及其在分类上的意义

基于Flora of China采用国际石松类和蕨类植物新分类系统,其水龙骨科(Polypodiaceae)不仅涵盖了秦仁昌分类系统中的水龙骨科(Polypodiaceae) 20多属,而且还包括槲蕨科(Drynariaceae)、鹿角蕨科(Platyceriaceae)等独立的科。水龙骨科(Polypodiaceae)新分类系统种类较多、分类复杂,需要对其合理性和孢粉学在新分类系统中的意义进行新的探讨。该文首次以新分类系统为依据,采用扫描电镜对山东分布的水龙骨科(Polypodiaceae)植物孢子形态及其周壁纹饰亚显微结构进行了系统地观察。结果表明:该科孢子形态为圆肾形,左右对称,具周壁,其周壁纹饰在种内稳定,在亚科、属及种间区别显著。孢粉学研究结果,支持槲蕨亚科、鹿角蕨亚科分别列于水龙骨科下的两个亚科;基于山东假瘤蕨孢子周壁纹饰,并结合叶片形态特征,山东假瘤蕨(Phymatopteris shandongensis J.X.Li et C.Y.Wang)应为一个独立的新种,不宜并入金鸡脚假瘤蕨[Phymatopteris hastata (Thunb.) Pic.Serm.]。依...     

CYTOGENETIC STUDIES IN THE GENUS TRIBOLIUM (POACEAE: ARUNDINEAE)

The genus Tribolium Desv. consists of nine species, i.e., T. utriculosum (Nees) Renv., T. ciliare (Stapf) Renv., T. echinatum (Thunb.) Desv., T. hispidum (Thunb.) Desv., T. acutiflorum (Nees) Renv., T. obliterum sensu Davidse, T. glomeratum sensu Davidse, T. uniolae (L.f.) Renv., and T. brachystachyum (Nees) Renv. The genus has a basic chromosome number of 6, and from diploid to hexaploid specimens have been examined. Precocious segregation of metaphase I bivalents were observed in four species. Multivalent formation results in unequal chromosome segregation during anaphase I, and several cells with an 11–13 chromosome distribution have been observed. The presence of univalents and anaphase I bridges in all T. brachystachyum specimens suggests a hybrid origin for the species. B-chromosomes were present in specimens from four species. The B-chromosomes are similar to the euchromosomes with the exception that they do not participate in meiosis. The B-chromosomes have a possible isochromosome origin. The cytogenetic evidence presented supports the combination of Plagiochloa and Lasiochloa into Tribolium and indicates that the genus is closely related to Urochlaena, whereas it is not closely related to Prionanthium.     

Pollen Morphology of Parnassia L. (Parnassiaceae) and Its Systematic Implications

The pollen morphology of 28 species of Parnassia L. was investigated with light microscopy and scanning electron microscopy (SEM). The shape of pollen grains in this genus varies from subspheroidal to prolate in equatorial view and is three-lobed circular in the polar view. Pollen grains are usually radially symmetrical, isopolar, tricolporate or syntricolporate, with reticulate sculpture. The pollen characteristics among species are fairly similar to each other. Morphological information regarding the pollen grains shows that Parnassia is a natural genus. Based on exine ornamentation observed under SEM, three types of pollen grains were recognized: (i) type Ⅰ, with foveolate-reticulate sculpture; (ii) type Ⅱ, with a finely reticulate sculpture; and (iii) type Ⅲ, with a coarsely reticulate sculpture. Most sections of this genus have one type of sculpture of pollen morphology, but Sect. Nectarotrilobos has three types of sculpture and Sect.Saxifragastrum has two types of sculpture. All three types of sculpture can be found in Southwest China,with species with the longest (Parnassia delavayi Franch.) and shortest (Parnassia faberi Oliv.) colpi,implying that Southwest China is the center of diversification of the genus.     

A prostrate species of myricaria in Eastern Himalaya and Yunnan

Summary

Under the name Myricaria germanica var. prostrata two species, both distinct from M. germanica (L.) Desv., have been confused, namely M. prostrata Hook. f. & Thoms. (syn. M. hedinii Paulsen) and M. rosea W. W. Smith, hitherto considered endemic to Yunnan but now known to extend westward to central Nepal.     

VOLATILE CONSTITUENTS OF CHAROPHYTES AS OVIPOSITION DETERRENTS OF CULEX PIPIENS PALLENS (DIPTERA: CULICIDAE)1

Four populations of charophytes (including three species), Chara inconnexa T. F. Allen (populations 1 and 2), C. vulgaris L., and Nitellopsis obtusa (Desv.) J. Groves, were studied for effective chemicals as oviposition deterrents of Culex pipiens pallens. The charophyte volatile organic compounds (VOCs) were retained in Tenax GR, subsequently desorbed using a thermal desorption cold trap injector (TCT), and analyzed by gas chromatography/mass spectrometry (GC/MS) to elucidate that charophytes have repellent properties. C. inconnexa (1) and C. inconnexa (2) exhibited strong repellent activities, and C. vulgaris showed some repellent activity against C. pipiens pallens with terpenes and benzothiazole playing major roles, while N. obtusa lacked those compounds and did not have an effect. These results suggest that charophytes have potential application as pesticides, but there are interspecific differences. In addition, benzene hydrocarbons were among the volatiles in Chara but not in N. obtusa, implying that some charophytes could be used to absorb these compounds.     

Notes on some tardigrades from Thailand,with descriptions of two new species

Abstract

Three species of tardigrades are reported from Thailand: Pseudechiniscus quadrilobatus Iharos, 1969, Calcarobiotus (Calcarobiotus) digeronimoi sp. n., and Mixibius sutirae sp. n. Calcarobiotus (C.) digeronimoi sp. n. has claws of Calcarobiotus type; those of the first three pairs of legs have a medial and a lateral spur, those of the hind legs lack basal spurs. Mixibius sutirae sp. n. has a densely sculptured dorsal cuticle and two macroplacoids; it lacks lunules and other thickenings on the legs. It is similar to Mixibius ornatus Pilato et al., 2001, from which it differs in characteristics of the cu‐ticular sculpture and by having the ventral surface unsculptured.     

中国实蕨属的分类修订

对实蕨属Bolbitis的17种植物的孢子进行了扫描电镜观察。根据孢子周壁特征,中国产实蕨属的孢子明显可分为3种类型：A型孢子具网状周壁,B型孢子具鸡冠状-波状周壁,C型孢子具平滑的波状周壁。孢子周壁特征、叶脉式样和叶片顶部的形态是实蕨属中最有价值的分类学性状。根据标本检查,结合野外调查和孢子形态观察,对中国产实蕨属的分类进行了修订,确定中国有实蕨属植物20种和3杂交种,其中包括2个新组合B. fengiana (Ching) S. Y. Dong和B. medogensis (Ching &; S. K. Wu) S. Y. Dong,以及2个中国新分布B. costata Ching ex C. Chr.和B. hookeriana K. Iwats.。将B. latipinna Ching、B. media Ching &; Chu H. Wang、B. yunnanensis Ching、Egenolfia crassifolia Ching、E. crenata Ching &; P. S. Chiu、E. fengiana Ching、E. medogensis Ching &; S. K. Wu和E. ×yunnanensis Ching &; P. S. Chiu等8个名称处理为新异名。文中给出了分种检索表、每个种的生境和分布资料、大多数种的特征集要和孢子扫描电镜照片。