Spore ornamentation in the Dryopteris spinulosa complex

1972 ◽  
Vol 50 (7) ◽  
pp. 1617-1621 ◽  
Author(s):  
D. M. Britton
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
North American ◽  
Spine Density ◽  
Spine Morphology ◽  
Spore Ornamentation ◽  
Clear Identification ◽  
Scanning Electron

The spores of five taxa of North American Dryopteris were studied with the scanning electron microscope. The taxa considered were two eastern diploids, D. intermedia (Muhl. ex Willd.) A. Gray and the eastern diploid of D. "dilatata”; two tetraploids, D. spinulosa (O. F. Muell.) Watt and D. campyloptera Clarkson; and one western diploid, D. assimilis S. Walker. All the taxa have spores with spines. Spine density and spine morphology are variable both within and between taxa and do not allow a clear identification of taxa using these characters alone. It is considered that all five taxa are closely related as evidenced by the similarities in their perine morphology as compared with species outside the complex.

scholarly journals Buotidae, a new family for the minute North American milliped Buotus carolinus (Chamberlin) 1940 (Diplopoda, Chordeumatida, Striarioidea)

Zootaxa ◽  
2009 ◽  
Vol 2290 (1) ◽  
pp. 41-49
Author(s):  
WILLIAM A. SHEAR
Keyword(s):  
United States ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
North American ◽  
The United States ◽  
Atlantic Region ◽  
New Family ◽  
To Receive ◽  
Scanning Electron

Buotus carolinus (Chamberlin) 1940, a minute, rarely collected but relatively widespread milliped of the mid-Atlantic region of the United States, was originally described as a member of the order Polyzoniida, family Polyzoniidae. Shear (1981) correctly placed the species in the order Chordeumatida and argued for assignment to the suborder Craspedosomatidea, superfamily Brannerioidea, family Tingupidae. New studies of fresh specimens using the scanning electron microscope, however, revealed characters inconsistent with this placement and instead support inclusion of Buotus in the suborder Striariidea, superfamily Striarioidea. Because the species cannot be accommodated in any of the established families of this superfamily, a new family Buotidae is herein erected to receive it.

The flagellum and tempers of some male tiger beetles (Coleoptera: Carabidae: Cicindelinae)

2016 ◽  
Vol 148 (4) ◽  
pp. 416-425
Author(s):  
Richard Freitag
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Functional Morphology ◽  
North American ◽  
Inverse Relationship ◽  
Tiger Beetle ◽  
Tiger Beetles ◽  
Free Flagellum ◽  
Scanning Electron ◽  
Shape And Size

AbstractThe male flagellum of 32 North American tiger beetle (Cicindela Linnaeus; Coleoptera: Carabidae: Cicindelinae) species was examined with a scanning electron microscope for new, stable characters that might be useful in studies of taxonomy and functional morphology. Two sets of characters were observed, shape and size of the flagellum, and the form and distribution of tempers (micro teeth-like structures on the surface of the flagellum). These characteristics were surprisingly uniform for most species. It is inferred that the inner walls of the female spermatheca duct are gripped by the male flagellum, achieved either by flexing the inserted temper-free long flagellum, or direct insertion by the temper-covered short flagellum. It is proposed that an inverse relationship pattern exists between the elongate temper-free flagellum, and the temper-covered shorter flagellum.

A scanning electron microscope study of the spores and selected peristomes of the North American Encalyptaceae (Musci)

1974 ◽  
Vol 52 (8) ◽  
pp. 1973-1981 ◽  
Author(s):  
Dale H. Vitt ◽  
Catherine D. Hamilton
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
North American ◽  
Cell Walls ◽  
Electron Microscope Study ◽  
Spore Morphology ◽  
Scanning Electron Microscope Study ◽  
Whole Cells ◽  
The North ◽  
Scanning Electron

The eight North American species of Encalypta can be readily distinguished on the basis of spore morphology as viewed in the scanning electron microscope. Descriptions are given of the spores of each species as well as those of Bryobrittonia pellucida. Although the spores of Bryobrittonia closely resemble those of Encalypta procera, Bryobrittonia is easily distinguished from all Encalypta species in having mammillose leaf cells. Based on spore polarity and ornamentation, Encalypta can be divided into three groups, these closely approximating groupings that have been proposed on the basis of peristome characteristics. Of the three peristomes examined, that of E. longicolla appears to consist of whole cells, that of E. brevicolla of both whole cells and cell walls, while the peristome of E. rhaptocarpa consists of cell walls only.

The Alteration of the Pore Spaces in Sandstones

1973 ◽  
Vol 31 ◽  
pp. 210-211
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Other ◽  
Coarse Grained ◽  
Depositional Fabric ◽  
Soluble Components ◽  
Scanning Electron ◽  
Shape And Size

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.

The Broad Applications of the Scanning Electron Microscope

1969 ◽  
Vol 27 ◽  
pp. 20-21
Author(s):  
C. T. Nightingale ◽  
S. E. Summers ◽  
T. P. Turnbull
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Light Microscopy ◽  
Surface Topography ◽  
Great Depth ◽  
Resolving Power ◽  
Depth Of Field ◽  
Pictorial Representations ◽  
Scanning Electron

The ease of operation of the scanning electron microscope has insured its wide application in medicine and industry. The micrographs are pictorial representations of surface topography obtained directly from the specimen. The need to replicate is eliminated. The great depth of field and the high resolving power provide far more information than light microscopy.

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

Resolution of a Transmitted Electron Image Formed by A Scanning Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 386-387
Author(s):  
S. Takashima ◽  
H. Hashimoto ◽  
S. Kimoto
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Objective Lens ◽  
Specimen Thickness ◽  
Probe Diameter ◽  
Transmission Electron ◽  
Electron Image ◽  
Conventional Transmission Electron Microscope ◽  
Scanning Electron

The resolution of a conventional transmission electron microscope (TEM) deteriorates as the specimen thickness increases, because chromatic aberration of the objective lens is caused by the energy loss of electrons). In the case of a scanning electron microscope (SEM), chromatic aberration does not exist as the restrictive factor for the resolution of the transmitted electron image, for the SEM has no imageforming lens. It is not sure, however, that the equal resolution to the probe diameter can be obtained in the case of a thick specimen. To study the relation between the specimen thickness and the resolution of the trans-mitted electron image obtained by the SEM, the following experiment was carried out.

Characterization of Sputtered Films using the Scanning Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 44-45
Author(s):  
R. F. Schneidmiller ◽  
W. F. Thrower ◽  
C. Ang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Sputtered Films ◽  
Plasma Sputtering ◽  
Microelectronic Devices ◽  
Control Film ◽  
Scanning Electron

Solid state materials in the form of thin films have found increasing structural and electronic applications. Among the multitude of thin film deposition techniques, the radio frequency induced plasma sputtering has gained considerable utilization in recent years through advances in equipment design and process improvement, as well as the discovery of the versatility of the process to control film properties. In our laboratory we have used the scanning electron microscope extensively in the direct and indirect characterization of sputtered films for correlation with their physical and electrical properties.Scanning electron microscopy is a powerful tool for the examination of surfaces of solids and for the failure analysis of structural components and microelectronic devices.

Field Emission SEM Equipped With Noise Compensator

1973 ◽  
Vol 31 ◽  
pp. 302-303
Author(s):  
S. Saito ◽  
H. Todokoro ◽  
S. Nomura ◽  
T. Komoda
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Low Contrast ◽  
Probe Current ◽  
High Resolution Images ◽  
Scanning Electron

Field emission scanning electron microscope (FESEM) features extremely high resolution images, and offers many valuable information. But, for a specimen which gives low contrast images, lateral stripes appear in images. These stripes are resulted from signal fluctuations caused by probe current noises. In order to obtain good images without stripes, the fluctuations should be less than 1%, especially for low contrast images. For this purpose, the authors realized a noise compensator, and applied this to the FESEM.Fig. 1 shows an outline of FESEM equipped with a noise compensator. Two apertures are provided gust under the field emission gun.

Visualization of Internal Skin Structures with the Scanning Electron Microscope

1969 ◽  
Vol 27 ◽  
pp. 46-47
Author(s):  
Emil Bernstein
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Great Depth ◽  
Hair Follicles ◽  
Depth Of Field ◽  
Pig Skin ◽  
Realistic Picture ◽  
Main Components ◽  
Scanning Electron

An interesting method for examining structures in g. pig skin has been developed. By modifying an existing technique for splitting skin into its two main components—epidermis and dermis—we can in effect create new surfaces which can be examined with the scanning electron microscope (SEM). Although this method is not offered as a complete substitute for sectioning, it provides the investigator with a means for examining certain structures such as hair follicles and glands intact. The great depth of field of the SEM complements the technique so that a very “realistic” picture of the organ is obtained.

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