Mallomonas connensis sp. nov., a new species of Synurophyceae from a small New England lake, U.S.A.

A new species of Mallomonas, M. connensis sp. nov., is described from a eutrophic locality in Connecticut, U.S.A. with a relatively high pH and specific conductance. Cells are covered with bristles and have scales that are orientated with their longitudinal axes perpendicular to the longitudinal axis of the cell. Each scale of the apical ring is highly asymmetrical with a forward projecting triangular shaped extension; collectively the extensions form an opening through which the flagellum emerges. Body scales possess a prominent Ushaped ridge that transverses the scale near the center and extends forward. A series of more or less concentric ribs cover the U-shaped ridge and dome, and circumscribe a more light and electron transparent region. The combination of characters of the bristles is unique among taxa of Mallomonas .     

Mallomonas wujekii (Synurophyceae), a new species from Florida, U.S.A.

A new species of Mallomonas, M. wujekii sp. nov., belonging to the Series Tonsuratae is described from a dilute, acidic locality in Florida, U.S.A. Bristle bearing domed scales are restricted to the anterior end, and scales are orientated with their longitudinal axes at a 60° to 90° angle with the longitudinal axis of the cell. Cells have three types of scales, domed anterior scales, domeless body scales and spined posterior scales. All scales possess papillae that are restricted to the shield and have one rib positioned on each end of the posterior flange. The new species is believed to be most closely related to Mallomonas tonsurata and M. galeiformis . The combination of characters of the bristles is unique among taxa of Mallomonas .     

Raphidiophrys heterophryoidea sp. nov. (Centrohelida: Raphidiophryidae), the first heliozoan species with a combination of siliceous and organic skeletal elements

Centrohelid heliozoans form a monophyletic group with uncertain affinities to other groups of protists. Except for a number of naked species, they have either siliceous scales or organic spicules covering the cell. According to the phylogenetic analysis of the 18S rDNA gene, it is hypothesized that scales are the ancestral form of cell coverings, while spicules are derived structures. The present paper describes a new species of centrohelids, Raphidiophrys heterophryoidea, isolated from the inner lakes of Valamo Island (North-Western Russia). This species has tangential scales, consisting of two plates, connected with radial, sometimes branched septa. Raphidiophrys heterophryoidea also has radially oriented spindle-shaped spicules. The organic nature of spicules and the siliceous nature of scales were verified by energy-dispersive X-ray microanalysis. Such a combination of organic and siliceous skeletal elements in one heliozoan is novel for any heliozoan species. The complex bipartite structure of scales suggested placing this new species in the genus Raphidiophrys. Consequently, the diagnoses of the genus Raphidiophrys and the family Raphidiophryidae were amended taking into account the optional presence of spicules. Raphidiophrys heterophryoidea presumably represents a stage of shift from scales to spicules, which, according to the molecular phylogenetic data, occurred at least twice in centrohelid evolution.     

Mallomonas nieringii sp. nov., a new species of Synurophyceae from a suite of ponds on Cape Cod, Massachusetts, U.S.A.

A new species of Mallomonas, M. nieringii sp. nov., is described from a small, poorly buffered, acidic locality on Cape Cod, Massachusetts, U.S.A. Cells are covered with uniquely sculptured scales, each scale of which may possess a single bristle. Cell, scale and bristle morphology all indicate that this new species should be placed within the series Punctiferae of the section Punctiferae, which now has four recognized species and one variety. Scales of the apical ring are highly asymmetric in design, each with a forward projecting triangular shaped spine. Collectively, the triangular shaped extensions of the apical ring of scales surround a single emergent flagellum. Body scales resemble those of Mallomonas punctifera and M. transsylvanica in shape and general morphology, but differ in lacking distinct secondary ribbing on the shield. Mallomonas nieringii was found in six waterbodies all situated within a small geographic area on the outer tip of the Cape Cod peninsula.     

Thielavia gigaspora, a new thermotolerant ascomycete from Egypt

Thielavia gigaspora sp. nov. from herbivore dung is described and illustrated. The new taxon by comparison with previously known species is distinguished by relatively large ascospores (25-38x15-21mum), each showing an apical, protuberant germ pore and a longitudinal dark band. A brief comparison with morphologically related species is given.     

THE ONTOGENY OF CARBONIFEROUS ARTICULATES: THE APEX OF SPHENOPHYLLUM

Twig apices of Sphenophyllum lescurianum, S. constrictum, and two new Sphenophyllum taxa are described in transverse and longitudinal section from middle and upper Pennsylvanian age specimens. In all of the species the single apical cell has the shape of a tetrahedron, with a triangular upper surface and three internal cutting faces. Segment cells are produced from each of the cutting surfaces in a dextrorse or sinistrorse direction, depending upon the species. The central portion of each segment cell contributes to the initiation of the procambium, while the remaining outer portion undergoes a vertical and subsequent horizontal division to form segment cells. Segment cells are aligned in vertical tiers beneath the respective apical cell cutting faces, with the individual leaves positioned directly beneath a tier of segment cells. Leaf primordia are first observed as a series of surface undulations below the apex, with an intercalary meristem located directly beneath each primordium. The vegetative apical organization of Sphenophyllum is demonstrated to be very similar to the type of organization found at the stem tips of Catamites and Equisetum.     

Two sympatric new species of woodlizards (Hoplocercinae, Enyalioides) from Cordillera Azul National Park in northeastern Peru

We report the discovery of two sympatric new species of Enyalioides from a montane rainforest of the Río Huallaga basin in northeastern Peru. Among other characters, the first new species is distinguishable from other Enyalioides by the combination of the following characters: strongly keeled ventral scales, more than 37 longitudinal rows of dorsals in a transverse line between the dorsolateral crests at midbody, low vertebral crest on the neck with vertebrals on neck similar in size to those between hind limbs, projecting scales on body or limbs absent, 96 mm maximum SVL in both sexes, and caudals increasing in size posteriorly within each autotomic segment. The second new species differs from other species of Enyalioides in having strongly keeled ventral scales, scales posterior to the superciliaries forming a longitudinal row of strongly projecting scales across the lateral edge of the skull roof in adults of both sexes, 31 or fewer longitudinal rows of strongly keeled dorsals in a transverse line between the dorsolateral crests at midbody, vertebrals on neck more than five times the size of vertebrals between hind limbs in adult males, projecting scales on body or limbs absent, and caudals increasing in size posteriorly within each autotomic segment. We also present an updated molecular phylogenetic tree of hoplocercines including new samples of Enyalioides rudolfarndti, Enyalioides rubrigularis, both species described in this paper, as well as an updated identification key for species of Hoplocercinae.     

The taxonomy of problematic Mallomonas species (Synurophyceae). I. Mallomonas hindonii and M. canina

Whole cells with complete cell armour (siliceous scales and bristles) of Mallomonas hindonii and Mallomonas canina (Synurophyceae) have been found in Ontario. It is concluded that these two species are not synonymous, as has been suggested previously, and attention is given to structural features of scales and bristles which can be used to distinguish between them. Both species are restricted to softwater/acidic environments.     

Detailed Process of Shell Construction in the Photosynthetic Testate Amoeba Paulinella chromatophora (Euglyphid,Rhizaria)

Most euglyphids, a group of testate amoebae, have a shell that is constructed from numerous siliceous scales. The euglyphid Paulinella chromatophora has photosynthetic organelles (termed cyanelles or chromatophores), allowing it to be cultivated more easily than other euglyphids. Like other euglyphids, P. chromatophora has a siliceous shell made of brick‐like scales. These scales are varied in size and shape. How a P. chromatophora cell makes this shell is still a mystery. We examined shell construction process in P. chromatophora in detail using time‐lapse video microscopy. The new shell was constructed by a specialized pseudopodium that laid out each scale into correct position, one scale at a time. The present study inferred that the sequence of scale production and secretion was well controlled.     

Morphological investigations of the frustule, perizonium and initial valves of the freshwater diatom Achnanthes crenulata Grunow (Bacillariophyceae)

The present study clarifies the fine structure of the vegetative frustules, initial valves and perizonium of Achnanthes crenulata Grunow. The valves of the vegetative cell are distinctly linear‐lanceolate with an undulate margin. The valve face is quite flat and in girdle view is smoothly curved as in species of Gephyria (Bacillariophyceae). However, the valve face of the initial cells is slightly rounded and does not have an undulate margin. Furthermore, the rapheless sternum is centrally positioned along the apical axis of the araphid initial valve. As this taxon develops from auxospore to initial valve, it forms only longitudinal perizonial bands; no transverse bands arise. The perizonium consists of three silicified bands: one large, central longitudinal plate and two bands that underlie this plate; these two bands are either open or closed. This taxon has several conspicuous structures compared to other marine species of Achnanthes, but the structure of the perizonium supports the position of A. crenulata within Achnanthes sensu stricto.     

STRUCTURE AND HISTOGENESIS OF THE EMBRYO OF ACER SACCHARINUM. I. EMBRYO SAC AND PROEMBRYO

Structure of the embryo sac and development of the proembryo of Acer saccharinum L. are described from paraffin sections. The embryo sac is monosporic and identical to the 8-nucleate Polygonum type in all respects. Cell, nuclear, and nucleolar sizes are constant within a narrow range and sharply distinctive for all components of the mature sac. Polar nuclei fuse before double fertilization. The longitudinal axis of symmetry of the egg, zygote, and proembryo is variously oriented with respect to the longitudinal axis of the embryo sac and is determined by the point of attachment of the presumptive egg cell to the sac wall. Subsequent development of the young embryo is responsive to aligning factors within the embryo sac and is collateral with the longitudinal axis of the sac. The first segmentation is transverse to the longitudinal axis of the zygote; the second and third are transverse in the basal cell and longitudinal in the apical cell. Descendants of ci form a short irregular suspensor; ca and m give rise to the apical and basal halves respectively of the embryo proper. The contribution of the proembryonic tiers to the older embryo differs in embryos of different initial orientation. Distribution and orientation of mitosis in the proembryo are shown in two accumulation maps.     

A new species of Heterosentis Van Cleave, 1931 (Acanthocephala, Arhythmacanthidae), a parasite of pinguipedid fishes in the southwest Atlantic

A new species of arhythmacanthid acanthocephalan, Heterosentis martini n. sp., parasitic in the Argentinean sandperch Pseudopercis semifasciata (Cuvier) (Perciformes, Pinguipedidae) from the coasts of Argentina is described. Heterosentis martini n. sp. differs from all congeneric species by having 10 longitudinal rows of hooks in the proboscis, each with 7-8 hooks, consisting of 1 medium apical and 3 larger sub-apical hooks with root, and 3-4 smaller, basal, curved hooks with rudimentary roots and spines in both ventral and dorsal regions of the body. The most similar species, Heterosentis heteracanthus (Linstow, 1896) Van Cleave, 1931, and Heterosentis brasiliensis Vieira, Felizardo and Luque, 2009, also have 10 longitudinal rows of hooks, but H. heteracanthus differs from the new species by having only 3-5 (more frequently 4) hooks in each row, with only the anterior hook large and bearing a developed root. Heterosentis brasiliensis differs from the new species by possessing 2 sub-apical hooks in each row (instead of 3), similar body length but shorter proboscis, and trunk spines restricted to the ventral surface of body.     

Development of mantle leaves inPlatycerium bifurcatum (Polypodiaceae)

InPlatycerium bifurcatum the leaf primordia emerge alternately right and left below the shoot apical cell on the dorsal surface of the rhizome. They arise from groups of small cells, a single large cell becoming the initial of the leaf apical cell. The longitudinal axis of the leaf apical cell is at a right angle to the rhizome axis and the leaf primordia are arranged longitudinally in two rows. The leaf apical cell gives rise to marginal initials which are responsible for leaf growth in one plain. Early marginal cells are crescent-shaped while the later ones are wedge-shaped. Hairy marginal cells appear in the very early stages of development. The interpretation of these cells as a promeristem and as initials are discussed.     

The auxospore wall of the marine diatom Melosira nummuloides (Dillw.) C. Ag. and related species

The auxospore wall of Melosira nummuloides C. A. Agardh is composed of two distinct parts, an organic layer and a layer of siliceous scales. Similar scales are reported from other species of the genus and their mode of formation is described. The possible phylogenetic significance of the two wall layers is discussed with respect to the two main groups of diatoms.     

Observations concerning the staining properties of the macroconidia of certain dermatophyton species.

Staining of the macroconidia of several Dermatophyton species by lactophenol-cotton blue was investigated. Young macroconidia stain variably; their cytoplasm may appear homogeneous or inhomogeneous. The possible explanation seems to be variation in the composition of the cytoplasm. In some macroconidia dark-staining filament was seen along the longitudinal axis. Mature macroconidia showed basal or basal+apical homogeneous deep staining. The intensive apical staining suggests that the apical structure differs from the structure of the side wall.     

Developmental anatomy of the shoot apical cell,rhizophore and root ofSelaginella uncinata

The developmental anatomy of the shoot apex, rhizophore and root ofSelaginella uncinata was examined by the semi-thin section method. The shoot apex has a single, lens-shaped apical cell with two cutting faces. Rhizophore primordia are initiated exogenously at the branching point of the second youngest lateral shoot. The rhizophore apex has a tetrahedral apical cell with three cutting faces. A pair of root primordia is initiated endogenously from inner cells of the rhizophore apex, after the rhizophore apical cell becomes unidentifiable losing its activity, and subsequently a root cap is formed from the distal face of the root apical cell. During the course of successive root branching the apical cell in an original root apical meristem becomes unidentifiable and then a new apical cell is initiated in each of the bifurcated root apical meristems. The root branching mode seems to be equivalent to the described dichotomous branching mode of fern shoots. Our results demonstrate a distinct morphogenetical difference between the rhizophore and the root, and confirm the exogenous origin of the rhizophore, as described for other species ofSelaginella. This evidence indicates that the rhizophore is not an aerial root but a leafless, root-producing axial organ.     

FRESHWATER HYPHOMYCETES OF THE NORTHERN APPALACHIAN HIGHLAND INCLUDING NEW ENGLAND,AND THREE COASTAL PLAIN STATES

Twenty-seven species of freshwater Hyphomycetes from two five-state areas in the northern Appalachian Highland, New England, and three Coastal Plain states were collected, isolated, and identified. The spores of three fungi which are probably aquatic Moniliales were also studied. Sigmoidea, a new Hyphomycete genus, includes submerged aquatic fungi which produce phialides laterally along the mycelium and sigmoid, multicellular phialospores. Varicosporium giganteum sp. n. produces terminal, hyaline, branched, and multiseptate aleuriospores. The main spore axis has one to four lateral branches which arise successively on one side of this axis. Tricladium marylandicum sp. n. is similar to T. splendens in that the lateral branches are constricted where each branch joins the main spore axis. It differs from this species in that the spore has a blunt apical cell on the main axis and on each of the lateral axes. Three possible methods of dispersal are presented to explain the cosmopolitan distribution of freshwater Hyphomycetes.     

玉米胚胎发育、萌发与胚的结构及子叶二型性

运用扫描电镜与半薄切片技术,观察了玉米(Zea mays L.)的胚发育过程,得到以下认识:第一、关于原胚.玉米合子细胞分裂形成的原胚分为胚柄、胚基与胚体三部分.胚柄短小,寿命短暂.胚基具有生长带,纵向伸长长度大,胚基的上部参与形成胚根鞘,其余部分干缩后附在胚根鞘末端.第二、玉米胚的背腹极性及二型子叶.原胚初期胚体出现背腹极性,腹面的细胞小,细胞质稠密,液泡较少;背面的细胞较大,细胞质稠密度略低,液泡较多.原胚后期胚体分化为腹部与背部,腹部从腹面的中央突起,背部在腹部的周围(从左至右侧)及整个胚体背面.进入幼胚时期,腹部分化为胚芽鞘、生长锥、胚轴、胚根和胚根鞘(大部分).期间,胚芽鞘原基和根原始细胞的分化都从胚体的中轴部位开始,然后向两侧和四周扩展,表现出胚体腹面形态的两侧对称性.原胚的背部形成盾片原基,盾片原基经历向左、右、上、下的迅速扩展和加厚的生长,将整个腹部所分化形成的构件藏于盾片的纵沟之中,最后盾片从纵沟的边缘长出的左、右侧鳞均向胚体的中轴线生长,完整显示出玉米胚腹面的两侧对称.玉米胚由腹部顶端形成胚芽鞘和生长锥的情况与水稻胚的胚芽鞘(顶生子叶)和生长锥的形成相同,玉米的胚芽鞘也是顶生子叶,盾片则是侧生子叶.玉米异型子叶的由来在于胚体的背腹极性.第三、玉米胚的真实形态结构及胚胎发育时期的划分.玉米胚是一个胚轴,其顶部是具胚芽鞘的胚芽,中部是具侧生子叶(盾片)的胚轴,下部是具胚根鞘的胚根.盾片从背面到腹面包住整个胚轴系统,在胚的腹面上可见从盾片边缘衍生的左、右侧鳞的边缘相迭,只在接缝线的上、下端留下蝌蚪状的小孔,使胚芽鞘和胚根鞘的末端稍露出.胚胎发育分为4个时期: 1.原胚期--从合子细胞分裂开始至分化背部与腹部为止;2.腹部迅速分化期;3.盾片快速生长期;4.侧鳞生长、胚套形成期.第四、获取垂直于胚腹面正中央纵切面是正确认识玉米胚形态的关键.     

玉米胚胎发育、萌发与胚的结构及子叶二型性

运用扫描电镜与半薄切片技术,观察了玉米(Zea mays L.)的胚发育过程,得到以下认识：第一、关于原胚。玉米合子细胞分裂形成的原胚分为胚柄、胚基与胚体三部分。胚柄短小,寿命短暂。胚基具有生长带,纵向伸长长度大,胚基的上部参与形成胚根鞘,其余部分干缩后附在胚根鞘末端。第二、玉米胚的背腹极性及二型子叶。原胚初期胚体出现背腹极性,腹面的细胞小,细胞质稠密,液泡较少;背面的细胞较大,细胞质稠密度略低,液泡较多。原胚后期胚体分化为腹部与背部,腹部从腹面的中央突起,背部在腹部的周围(从左至右侧)及整个胚体背面。进入幼胚时期,腹部分化为胚芽鞘、生长锥、胚轴、胚根和胚根鞘(大部分)。期间,胚芽鞘原基和根原始细胞的分化都从胚体的中轴部位开始,然后向两侧和四周扩展,表现出胚体腹面形态的两侧对称性。原胚的背部形成盾片原基,盾片原基经历向左、右、上、下的迅速扩展和加厚的生长,将整个腹部所分化形成的构件藏于盾片的纵沟之中,最后盾片从纵沟的边缘长出的左、右侧鳞均向胚体的中轴线生长,完整显示出玉米胚腹面的两侧对称。玉米胚由腹部顶端形成胚芽鞘和生长锥的情况与水稻胚的胚芽鞘(顶生子叶)和生长锥的形成相同,玉米的胚芽鞘也是顶生子叶,盾片则是侧生子叶。玉米异型子叶的由来在于胚体的背腹极性。第三、玉米胚的真实形态结构及胚胎发育时期的划分。玉米胚是一个胚轴,其顶部是具胚芽鞘的胚芽,中部是具侧生子叶(盾片)的胚轴,下部是具胚根鞘的胚根。盾片从背面到腹面包住整个胚轴系统,在胚的腹面上可见从盾片边缘衍生的左、右侧鳞的边缘相迭,只在接缝线的上、下端留下蝌蚪状的小孔,使胚芽鞘和胚根鞘的末端稍露出。胚胎发育分为4个时期：1．原胚期——从合子细胞分裂开始至分化背部与腹部为止;2．腹部迅速分化期;3．盾片快速生长期;4．侧鳞生长、胚套形成期。第四、获取垂盲于胚腹面正中央纵切面是正确认识玉米胚形态的关键。     

Effects of Blue Light on Cell Elongation and Microtubule Orientation in Dark-Grown Gametophytes of Ceratopteris richardii

Gametophytes of Ceratopteris richardii developed into strap-shapedprothalli in the dark. The prothalli had an apical meristem,a subapical elongation zone and a basal zone where no growthoccurred. Continuous irradiation of blue light inhibited cellgrowth of the elongation zone, although red or far-red lighthad no effect on elongation. Cortical microtubules (MTs) ofsubapical cells reoriented from transverse to oblique or parallelto the growing axis during blue light inhibition. Each regionof the strap-shaped prothallus was irradiated with a micro-beamof blue light. Cell elongation in the subapical region was notinhibited by irradiation at the apical meristem. Irradiationof the subapical region inhibited cell elongation to a similarextent as the whole irradiation control. When a single elongatingcell at one side of the subapical region was irradiated by ablue microbeam, elongation was inhibited in a cell at the irradiateside only, resulting in a bowing prothallus. Cortical MTs reorientedfrom transverse to longitudinal to the cell axis in irradiatedcells only. The results indicate that each cell in the subapicalregion perceives blue light by itself, reorients only its corticalMTs and ceases only its cell elongation, independent of surroundingcells. (Received October 17, 1996; Accepted December 9, 1996)