Surface features of the light-colored ascospores of some applanate Hypoxylon species

1977 ◽  
Vol 55 (18) ◽  
pp. 2394-2398 ◽  
Author(s):  
Jack D. Rogers

Ascospores of Hypoxylon cycliscum, H. flosculosum, H. sulcatum, H. scriblita, H. melanaspis, H. heterostomum, H. tinctor, H. hemisphaericum, and H. punctulatum have been depicted as having smooth walls. Scanning electron microscopy reveals the walls of ascospores of these species to be intricately ornamented. The possible taxonomic significance of these observations is discussed.

1984 ◽  
Vol 54 (12) ◽  
pp. 874-882 ◽  
Author(s):  
T.K. Guha Roy ◽  
A.K. Mukhopadhyay ◽  
A.K. Mukherjee

1971 ◽  
Vol 49 (8) ◽  
pp. 1259-1261 ◽  
Author(s):  
Larry F. Grand ◽  
Royall T. Moore

Basidiospores of 13 North American species of Strobilomycetaceae were examined by scanning electron microscopy. Similarities and differences of surface features among species are discussed in relation to their possible role in the taxonomy of the family.


2000 ◽  
Vol 6 (3) ◽  
pp. 202-210
Author(s):  
Kevin T. Reynolds

Abstract At the species level, bryozoans (class Phylactolaemata) in the family Plumatellidae are difficult to organize taxonomically. Of principal concern is the absence of consistent distinguishing features due mainly to plasticity of the group, a common problem with soft-bodied invertebrates. Yet, within the last three decades, analysis of distinctive chitinous statoblasts—using scanning electron microscopy—has resolved certain taxonomic questions. I examined statoblasts from 30 similar collections, the majority from the midwestern United States, and identified four distinct subgroups. Also, nine new statoblast surface features were identified: fold, polar grooves, bead, cave, demarcation, parasutural zone, ridge, sutural band, and sutural knob. The surface features of floating statoblasts (floatoblasts) provide useful data for species identification. Most consistently useful in plumatellids is a suture which varies from one species to the next. Mound-like tubercles and net-like ridges are next in the extent of variability. Finally, folds and polar grooves are present but vary even within floatoblasts from the same colony. Analysis of the suture in Plumatella fungosa, over a 5-day germination period, reveals all features at the site remain intact regardless of the initial age of the floatoblast. Only the suture line itself splits lengthwise to permit emergence of the new animal.


1986 ◽  
Vol 64 (12) ◽  
pp. 3101-3112 ◽  
Author(s):  
Stephen Blackmore

Lophate pollen occurs in many members of tribes Arctoteae, Lactuceae, Mutisieae, and Vernonieae of the Compositae. Fifteen distinct patterns of echinolophate pollen and eight of psilolophate pollen are described and illustrated by scanning electron microscopy. A key is provided that enables the 23 patterns to be recognised. The full potential of lophate pollen as a source of taxonomic characters can only be achieved when the pattern of lophae present has been determined. The simple distinction between lophate and nonlophate pollen is rarely informative. The widespread occurrence of lophate pollen is attributed to convergent evolution and related to functional aspects of the pollen.


PhytoKeys ◽  
2020 ◽  
Vol 166 ◽  
pp. 1-28
Author(s):  
Agnieszka Rewicz ◽  
Jolanta Marciniuk ◽  
Paweł Marciniuk

The genus Taraxacum is one of the largest and taxonomically most complicated apomictic genera. Currently, it is considered to consist of over 2800 species placed within 60 sections. Due to the large number of species, and their uniform morphological design and plasticity of leaves, the identification of plants at the species level is challenging even for specialists. This problem significantly hinders the study of their properties and the rational use of these valuable medicinal and nutritional plants. This paper presents the results of research on the morphology and micromorphology of achenes of 28 Taraxacum species of sect. Palustria and for comparison one species per section of: Erythrosperma, Naevosa, Piesis, and Taraxacum. The achenes were measured with a stereoscopic microscope and a biometric program, and micromorphological studies were performed by scanning electron microscopy. It has been shown that traits associated with achene morphology and micromorphology have a high diagnostic value, allowing us to distinguish sections as well as species within the sect. Palustria. Based on the examined achene features, a dichotomous key for determining the studied species was constructed.


2019 ◽  
Vol 55 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Zoya M. Tsymbalyuk ◽  
Sergei L. Mosyakin ◽  
Lyudmila M. Nitsenko

Abstract Pollen morphology of representatives of the genera Succisa and Succisella in the flora of Ukraine was studied using light and scanning electron microscopy. Pollen grains in both taxa were tricolpate, prolate, rarely oblate-spheroidal or spheroidal; large-sized. Their outline in polar view was subcircular, rarely trilobate, in equatorial view elliptical or rarely circular. Colpi short, of variable width, margins irregular with distinct, narrow margo, and blunt or acute ends. Exine sculpture was echinate-microechinate. The revealed characteristics of pollen grains are taxonomically significant at the generic and specific levels, and they can be used in pollen analysis. Palynomorphological data are consistent with the results of recent molecular phylogenetic studies. Data on pollen morphology also confirm taxonomic circumscription of Succiseae V. Mayer & Ehrend. Pollen grains in Succiseae are characterized by a tricolpate aperture type, which was probably ancestral in Dipsacaceae s. str.


Sign in / Sign up

Export Citation Format

Share Document