Sexual reproduction in the Peronosporomycetes (chromistan fungi)

1995 ◽  
Vol 73 (S1) ◽  
pp. 712-724 ◽  
Author(s):  
Michael W. Dick
Keyword(s):  
Sexual Reproduction ◽  
Dense Body ◽  
Morphological Characters ◽  
Life History Strategies ◽  
Phylogenetic Systematics ◽  
Taxonomic Identification ◽  
Phylogenetic Significance ◽  
Key Words Meiosis ◽  
Internal Morphology ◽  
Ecological Implications

An overview of sexual reproduction in the Peronosporomycetes leads to the recognition of constant features and variable traits. Variation in characters is accorded different weighting depending on its use for taxonomic identification or phylogenetic systematics. The phylogenetic significance of features of gametangial morphogenesis, such as vacuolation and the patterns of nuclear meioses and abortions, can be related to morphological characters such as the persistence of periplasm and oogonial and oospore wall deposition. The cellular reorganization occurring in the oogonium and oospores, particularly in relation to the possible functions of the dense body vesicle system and the glucan, phosphate, and lipid oospore reserves, may be critical for the internal morphology of the mature oospore and its function. Such differences are valuable for morphometric analysis, which lends itself to new identification procedures. The ecological implications of these differences in the production of oogonia and oospores are considered; sexual reproduction (its frequency or absence) may be crucial for successful life-history strategies in biodiversity. Key words: meiosis, karyogamy, syngamy, morphogenesis, morphometry, wall membranes.

Taxonomy of the genus Thyonella (Holothuroidea: Dendrochirotida), with mention of the first record of T. sabanillaensis from the southwestern Atlantic Ocean

Zootaxa ◽  
2018 ◽  
Vol 4527 (1) ◽  
pp. 75
Author(s):  
LUCIANA MARTINS
Keyword(s):  
Pacific Ocean ◽  
Atlantic Ocean ◽  
First Record ◽  
Morphological Characters ◽  
Sem Analysis ◽  
Southwestern Atlantic ◽  
Internal Morphology ◽  
The Pacific ◽  
Southwestern Atlantic Ocean ◽  
The Pacific Ocean

The genus Thyonella currently comprises four species which occur in the Atlantic and Pacific Oceans. Thyonella mexicana is the only species known to occur in the Pacific Ocean. The main morphological characters used to distinguish Thyonella species are their dermal ossicles. Since the differences among these characters are subtle, this contribution provides a detailed description and comparison of the ossicle assemblage of the concerned taxa. In addition, description of the internal morphology of three of the concerned species is also provided. Further, this study reports on the first record of Thyonella sabanillaensis for the Southwestern Atlantic. A worldwide revision of the distributional records of Thyonella species is presented and their taxonomy is discussed, concluding that some traditional taxonomic characters should be used cautiously. A brief discussion about the importance of SEM analysis is also provided. 

scholarly journals The morphology of Cannabis sativa L. Achenes

2021 ◽  
Author(s):  
Steve Govinda Udai Naraine
Keyword(s):  
Cannabis Sativa ◽  
Morphological Characters ◽  
Life History Strategies ◽  
Plant Domestication ◽  
Phenotypic Differences ◽  
Evolution Of Life ◽  
Significant Divergence ◽  
High Concentrations ◽  
Herbarium Collections

Cannabis sativa L. has been domesticated for fibre, oilseed, and marijuana; it also occurs as ruderal plants. “Marijuana” refers to plants selected for high concentrations of the chemical tetrahydrocannabinol (THC), while “hemp” refers to plants low in concentration of THC and which are domesticated for either stem fibre or oilseed. In my first chapter I review the botany of cannabis, taxonomy and origins, ethnobotany, and crop ferality. In my second chapter, I performed a study where achenes (“seeds”) from herbarium collections representative of these classes of C. sativa were assessed for variation in morphological characters and pericarp resistance to fracture. Multivariate analysis of the data revealed significant divergence among the groups. In contrast to ruderal plants, domesticated plants (hemp or marijuana) possessed achenes that are significantly longer, heavier, covered with a less adherent perianth, and lacking a pronounced basal attenuation. These characteristics reflect traits that are advantageous in domesticated plants, and are consistent with the "domestication syndrome”. Marijuana achenes, in comparison with hemp achenes, are shorter and darker. Achenes of fibre cultivars are larger than the achenes of oilseed cultivars. Achenes of dioecious oilseed cultivars are larger than the achenes of monoecious oilseed cultivars. We propose several mechanisms by which this phenotypic divergence may have occurred, including potential differences in outcrossing rate and the evolution of life history strategies among C. sativa groups that deserve further exploration. While only one species of Cannabis merits recognition, we postulate these phenotypic differences in C. sativa are a result of domestication for different purposes. In my final chapter I discuss the limitations and future studies. This work contributes a more complete understanding of cannabis morphology to the greater body of literature on plant domestication.

scholarly journals The morphology of Cannabis sativa L. Achenes

2021 ◽  
Author(s):  
Steve Govinda Udai Naraine
Keyword(s):  
Cannabis Sativa ◽  
Morphological Characters ◽  
Life History Strategies ◽  
Plant Domestication ◽  
Phenotypic Differences ◽  
Evolution Of Life ◽  
Significant Divergence ◽  
High Concentrations ◽  
Herbarium Collections

Cannabis sativa L. has been domesticated for fibre, oilseed, and marijuana; it also occurs as ruderal plants. “Marijuana” refers to plants selected for high concentrations of the chemical tetrahydrocannabinol (THC), while “hemp” refers to plants low in concentration of THC and which are domesticated for either stem fibre or oilseed. In my first chapter I review the botany of cannabis, taxonomy and origins, ethnobotany, and crop ferality. In my second chapter, I performed a study where achenes (“seeds”) from herbarium collections representative of these classes of C. sativa were assessed for variation in morphological characters and pericarp resistance to fracture. Multivariate analysis of the data revealed significant divergence among the groups. In contrast to ruderal plants, domesticated plants (hemp or marijuana) possessed achenes that are significantly longer, heavier, covered with a less adherent perianth, and lacking a pronounced basal attenuation. These characteristics reflect traits that are advantageous in domesticated plants, and are consistent with the "domestication syndrome”. Marijuana achenes, in comparison with hemp achenes, are shorter and darker. Achenes of fibre cultivars are larger than the achenes of oilseed cultivars. Achenes of dioecious oilseed cultivars are larger than the achenes of monoecious oilseed cultivars. We propose several mechanisms by which this phenotypic divergence may have occurred, including potential differences in outcrossing rate and the evolution of life history strategies among C. sativa groups that deserve further exploration. While only one species of Cannabis merits recognition, we postulate these phenotypic differences in C. sativa are a result of domestication for different purposes. In my final chapter I discuss the limitations and future studies. This work contributes a more complete understanding of cannabis morphology to the greater body of literature on plant domestication.

scholarly journals AN INTEGRATIVE TAXONOMY OF MOLECULAR AND TRADITIONAL APPROACHES FOR IDENTIFICATION OF A STORAGE MITE, ALEUROGLYPHUS OVATUS (ACARI: ASTIGMATA: ACARIDAE) IN MALAYSIA

2016 ◽  
Vol 6 (2) ◽  
pp. 882-889
Author(s):  
Ernieenor Faraliana Che Lah
Keyword(s):  
Molecular Identification ◽  
Dna Sequences ◽  
Correct Diagnosis ◽  
Morphological Characters ◽  
Integrative Taxonomy ◽  
Its2 Region ◽  
Morphological Identification ◽  
Taxonomic Identification ◽  
Internal Transcribed Spacer Region ◽  
Accurate Identification

A reliable and rapid taxonomic identification of a mite is the basis for a correct diagnosis of important mite associated allergies as they produce species-specific allergens. A double approach (molecular and morphological) to the taxonomic identification of Aleuroglyphus ovatus was presented. Molecular identification was performed with amplification of the internal transcribed spacer region (ITS2), whilst morphological characters were examined under light microscope. The BLAST results obtained from molecular analysis of A. ovatus was shown to be in concordance with the morphological identification with 97% genetic similarity. Thus, the molecular identification based on the ITS2 region can be applied as a reliable and efficient tool for species identification of Aleuroglyphus and probably any other astigmatid mites. Our findings suggest the need for a broad taxonomic sampling especially from closely related species for an accurate identification of local mites using both DNA sequences and morphology.

scholarly journals Short Communication: Leaf architectural characteristics of Cinnamomum cebuense Kosterm. (Lauraceae) distributed in different geographical locations, taxonomic identification and conservation concerns

2019 ◽  
Vol 21 (1) ◽  
Author(s):  
Edgardo Lillo ◽  
INOCENCIO E. BUOT JR ◽  
ARCHIEBALD B. MALAKI ◽  
STEVE MICHAEL T. ALCAZAR ◽  
RAAMAH ROSALES ◽  
...  
Keyword(s):  
Working Group ◽  
Short Communication ◽  
Morphological Characters ◽  
Taxonomic Identification ◽  
Endemic Plant ◽  
Leaf Architecture ◽  
In The Wild ◽  
Architectural Characteristics ◽  
Endemic Plant Species ◽  
Geographical Locations

Abstract. Lillo EP, Buot IE Jr., Malaki AB, Alcazar SMT, Rosales R, Diaz JLB, Redoblado BR, Gealon GGG. 2019. Short Communication: Leaf architectural characteristics of Cinnamomum cebuense Kosterm. (Lauraceae) distributed in different geographical locations, taxonomic identification and conservation concerns. Biodiversitas 20: 246-251. Populations of Cinnamomum cebuense Kosterm distributed in three geographic locations were examined in the study. The primary aim of the study was to compare the leaf architectural characteristics of Cinnamomum cebuense Kosterm. (Lauraceae) species distributed in three locations. Specimen morphological characters were described using the Leaf Architecture Working Group (LAWG) Manual. Results showed that the species from Nug-as, Alcoy, Cebu was Cinnamomum cebuense because majority of its leaf architectural characteristics and vein categories were similar to those from Tabunan forest. However, the Cinnamomum species from Mount Nacolod, Southern Leyte was slightly different because there are vein categories and other leaf characteristics not similar to those collected from Tabunan forest. The species as one of the endemic plant species on the island of Cebu need to be conserved and protected as they are endangered in the wild.  

scholarly journals Corrigenda: Phylogenetic relationship of catshark species of the genus Scyliorhinus (Chondrichthyes, Carcharhiniformes, Scyliorhinidae) based on comparative morphology. Zoosystematics and Evolution 96(2): 345–395. https://doi.org/10.3897/zse.96.52420

2020 ◽  
Vol 96 (2) ◽  
pp. 637-637
Author(s):  
Karla D. A. Soares ◽  
Marcelo R. de Carvalho
Keyword(s):  
Phylogenetic Relationships ◽  
Comparative Morphology ◽  
Sister Group ◽  
Morphological Characters ◽  
Data Matrix ◽  
Internal Morphology ◽  
The Family ◽  
Almost All ◽  
Relationship Of ◽  
Meristic Data

The genus Scyliorhinus is part of the family Scyliorhinidae, the most diverse family of sharks and of the subfamily Scyliorhininae along with Cephaloscyllium and Poroderma. This study reviews the phylogenetic relationships of species of Scyliorhinus in the subfamily Scyliorhininae. Specimens of all Scyliorhinus species were examined as well as specimens of four of the 18 species of Cephaloscyllium, two species of Poroderma, representatives of almost all other catshark (scyliorhinid) genera and one proscylliid (Proscyllium habereri). A detailed morphological study, including external and internal morphology, morphometry and meristic data, was performed. From this study, a total of 84 morphological characters were compiled into a data matrix. Parsimony analysis was employed to generate hypotheses of phylogenetic relationships using the TNT 1.1. Proscyllium habereri was used to root the cladogram. The phylogenetic analysis, based on implied weighting (k = 3; 300 replications and 100 trees saved per replication), resulted in three equally most parsimonious cladograms with 233 steps, with a CI of 0.37 and an RI of 0.69. The monophyly of the subfamily Scyliorhininae is supported as well as of the genus Scyliorhinus, which is proposed to be the sister group of Cephaloscyllium. The phylogenetic relationships amongst Scyliorhinus species are presented for the frst time.

ORPHOLOGICAL VARIATIONS FOR THE TAXONOMIC IDENTIFICATION OF SOME SPECIES OF ACACIA FROM ZARIA, KADUNA STATE NIGERIA

2021 ◽  
Vol 5 (1) ◽  
pp. 233-243
Author(s):  
Halima Salisu ◽  
A. U. Khan ◽  
B. Y. Abubakar ◽  
S. Namadi
Keyword(s):  
Morphological Characters ◽  
Leaf Margin ◽  
Taxonomic Identification ◽  
Morphological Variations ◽  
Acacia Species ◽  
Daunting Task ◽  
The Family ◽  
Morphological Measurement ◽  
Acacia Sieberiana

Acacia belongs to the family fabaceae among the largest legume genera consisting of eighteen species with the majority of the species distributed in tropical and sub-tropical Africa. Classification of Acacia have remained a daunting task due to it wide spread and also hampered by is large number of species ,prevalence of morphological convergence. Morphological variations in foliar, thorn, inflorescence of some Acacia species found in Zaria for their taxonomic identification at species level were evaluated were Seven species and one variety of Acacia were taxonomically classified using morphological characters. In almost the species leaves were compound bipinnate, alternate and pinnulesare oblong. However the pinnules of A. senegal are obovate. In A. auriculiformis the leaves are simple and sickle-like in shape. Leaves texture ranges from glabrous to pubescent and leaf margin were entire in all the species. The morphological measurement parameters were analyzed using ANOVA cooperation and the results indicate variations among the species. The variations observed in some of the characters could be of taxonomic importance in the identification of the species. Overall ranking indicated that Acacia sieberiana var  sieberiana and Acacia sieberiana var villosa were the best with high values of morphological characters of pinna length (3.50±0.11 cm and 3.82±0.16 cm respectively) and number of pinna (18.80±1.32 and 41.70±1.52 respectively). The high values of pinna could be used in solving taxonomic problems associated with Acacia species and in mapping out breeding strategies for the production of cultivars with better foliar yield of Acacia species in Nigeria

An updated generic circumscription for Cryptangieae (Cyperaceae, Poales) based on a molecular phylogeny and a morphological character reconstruction

Phytotaxa ◽  
2021 ◽  
Vol 483 (3) ◽  
pp. 211-228
Author(s):  
SUZANA M. COSTA ◽  
FABIO A. VITTA ◽  
WILLIAM W. THOMAS ◽  
A. MUTHAMA MUASYA ◽  
ROSEMERI MOROKAWA ◽  
...  
Keyword(s):  
Bayesian Inference ◽  
Molecular Phylogeny ◽  
Morphological Character ◽  
Morphological Characters ◽  
New Combinations ◽  
Phylogenetic Significance ◽  
Generic Level ◽  
Molecular Analyses ◽  
Character Reconstruction ◽  
The Relationship

Cryptangieae is a monophyletic tribe, as asserted in a recent molecular hypothesis, but there are questions about the circumscription and relationships of its genera. We enlarged the sampling of the tribe diversity, including about 80% of known species, and provide new analyses using single and combined matrices from two chloroplast (rbcL and trnL-F) and three nuclear ribosomal (ITS, ETS and 5S-NTS) regions with Bayesian Inference to clarify these questions. We also performed character reconstruction analyses with diagnostic morphological characters, including some traditionally applied in Cryptangieae taxonomy, using parsimony methods. The molecular analyses show Lagenocarpus in the current circumscription as polyphyletic, and the need to merge Cephalocarpus and Everardia to avoid paraphyletic genera. We propose an updated circumscription following the phylogeny, including a new name to a group at generic level (Krenakia); and discuss the phylogenetic significance of the morphological characters in Cryptangieae taxonomy. Though the relationship among some genera still needs more research, the genera we propose are strongly supported clades with clear morphological synapomorphies. Additionally, we provide an identification key, a brief description of genera and a list of accepted species including the required new combinations.

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