A re-evaluation of species limits in Canadian Arctic Island Puccinellia (Poaceae): resolving key characters

2001 ◽  
Vol 79 (8) ◽  
pp. 927-956 ◽  
Author(s):  
L L Consaul ◽  
L J Gillespie
Keyword(s):  
Principal Components ◽  
Canadian Arctic ◽  
Small Degree ◽  
Species Boundaries ◽  
Key To Species ◽  
Species Complexes ◽  
Morphometric Analyses ◽  
Species Groups ◽  
Components Analysis ◽  
Variation Explained

This study examined morphological variation for species of Puccinellia that have traditionally posed problems of identification in the Canadian Arctic Archipelago. The first part of the study involved a re-examination of several characters that were difficult to define or describe. Microscopic examination of lemma and glume apices revealed that the characters "erose-ciliolate" lemma and glume apex margins are more accurately divided into two characters: degree to which they are erose, and presence of trichomes. These trichomes consist of acute or acuminate cells that protrude 15–35 µm from the margin, sometimes with a spinulose tip up to 10 µm long. The term "thickened pedicel" is clarified to mean thickened below the apex in relation to the apex. The second part of the study involved preliminary morphometric analyses on the above-mentioned revised characters, plus other characters previously shown to have low plasticity in this genus, for 10 recognized species that are difficult to distinguish. Many species or species complexes resolved to a small degree, but no taxa formed distinct groups. Correlations among many characters were low, accounting for a low percentage of variation explained by the first few principal components. Hypotheses of species boundaries and a preliminary revised key to species and species groups, incorporating findings from this study, are presented.Key words: Puccinellia, Canadian Arctic, morphology, trichomes, principal components analysis, cluster analysis.

scholarly journals Resolving the anomaly of Lomatium anomalum: discovery of a new species in southwestern Idaho (U.S.A.) Lomatium andrusianum (Apiaceae)

2018 ◽  
Vol 12 (1) ◽  
pp. 1-15
Author(s):  
Mckayla Stevens ◽  
Donald H. Mansfield ◽  
James F. Smith ◽  
Mary Ann E. Feist
Keyword(s):  
New Species ◽  
Principal Components Analysis ◽  
Principal Components ◽  
Species Boundaries ◽  
Monophyletic Clade ◽  
Ecological Data ◽  
Components Analysis ◽  
Multiple Species ◽  
Vegetative Characters ◽  
A New Species

Apparent polyphyly within the unresolved clade of Lomatium (Apiaceae) containing L. triternatum, L. anomalum, L. thompsonii, and L. packardiae suggests conflict among current taxonomic classification schemes. To recover this clade and more clearly define species boundaries, we examined populations of L. anomalum from three geographic regions in Idaho and adjacent Oregon. Using phylogenetic, morphological, and ecological data, we conclude that the L. anomalum complex currently circumscribes multiple species. Phylogenetic analysis of the nuclear ribosomal ITS and ETS, and cpDNA rpl32-trnLUAG, rps-16 intron, trnD-trnT, ndhA intron, and psbA-trnH recovered populations from the Boise foothills as a distinct, monophyletic clade. Principal Components Analysis of 30 reproductive and vegetative characters show two distinct groups: one of Boise foothills and one of the combined Mann Creek and Camas Prairie vicinities. Principal Components Analysis of 16 soil characteristics show that soils occupied by Boise foothills populations are distinct from those occupied by Mann Creek and Camas Prairie populations. Based on phylogenetic, morphometric, and ecologic criteria, populations of what had been considered L. anomalum from the Boise foothills and vicinity are here described as a new species—Lomatium andrusianum. 

Soil surface lichens in arid and subarid south-eastern Australia. II. Phytosociology and geographic zonation

1972 ◽  
Vol 20 (2) ◽  
pp. 215 ◽  
Author(s):  
RW Rogers
Keyword(s):  
Principal Components Analysis ◽  
Principal Components ◽  
Group Identification ◽  
Soil Surface ◽  
The Other ◽  
Influence Analysis ◽  
South Eastern ◽  
Eastern Australia ◽  
Species Groups ◽  
Components Analysis

Five lichen species groups were delimited, principal components analysis and influence analysis being used as aids to group identification. With these same techniques it was demonstrated that two of the species groups formed "background" floras in adjacent geographic areas, the other three species groups, being superimposed upon the "background" floras to produce five separate geographic zones of lichen distribution.

Delimiting species boundaries within the Bothriochloa saccharoides complex (Poaceae) through morphometric analysis

Phytotaxa ◽  
2013 ◽  
Vol 89 (1) ◽  
pp. 24
Author(s):  
LIDIA R. SCRIVANTI ◽  
GUILLERMO A. NORRMANN ◽  
ANA M. ANTON
Keyword(s):  
Discriminant Analysis ◽  
Morphometric Analysis ◽  
Principal Components ◽  
Morphological Variation ◽  
Species Complex ◽  
Morphological Characters ◽  
Chemical Data ◽  
Species Boundaries ◽  
Herbarium Specimens ◽  
Components Analysis

The Bothriochloa saccharoides complex is one of the most interesting groups within the genus Bothriochloa (Poaceae). The plants inhabit grasslands of tropical and subtropical regions from the Americas. Principal components analysis (PCA) and discriminant analysis (DA) were employed to evaluate the morphological variation among 60 herbarium specimens tentatively identified as B. imperatoides, B. laguroides, B. longipaniculata, B. saccharoides and B. torreyana. Twenty-three morphological characters were included in the analysis in order to clarify problematic species boundaries. Chemical data was incorporated to improve the resolution on delimitation of the species complex. Taxa were delimited according to the observed clustering of specimens in the PCA plots and discriminant analysis, and diagnostic characters were identified. The results showed that five taxa could be distinguished on the basis of morphological characters and chemical data. Two new subspecies are described: B. saccharoides subsp. americana and B. saccharoides subsp. australis. An identification key and a taxonomic synopsis are provided.

Diagnoses Generated by Numerical Taxonomic Methods Applied to Standard Blood Variables

1980 ◽  
Vol 19 (04) ◽  
pp. 205-209
Author(s):  
L. A. Abbott ◽  
J. B. Mitton
Keyword(s):  
Liver Cirrhosis ◽  
Renal Disease ◽  
Principal Components Analysis ◽  
Discriminant Function ◽  
Principal Components ◽  
Discriminant Function Analysis ◽  
Chronic Renal Disease ◽  
Function Analysis ◽  
Infectious Hepatitis ◽  
Components Analysis

Data taken from the blood of 262 patients diagnosed for malabsorption, elective cholecystectomy, acute cholecystitis, infectious hepatitis, liver cirrhosis, or chronic renal disease were analyzed with three numerical taxonomy (NT) methods : cluster analysis, principal components analysis, and discriminant function analysis. Principal components analysis revealed discrete clusters of patients suffering from chronic renal disease, liver cirrhosis, and infectious hepatitis, which could be displayed by NT clustering as well as by plotting, but other disease groups were poorly defined. Sharper resolution of the same disease groups was attained by discriminant function analysis.

Discovery of Systenus in the Afrotropical Region with a description of a new species (Diptera: Dolichopodidae)

2009 ◽  
Vol 18 (2) ◽  
pp. 285-290
Author(s):  
I.Ya. Grichanov ◽  
M.B. Mostovski
Keyword(s):  
New Species ◽  
Key To Species ◽  
Afrotropical Region ◽  
Species Groups ◽  
First Time ◽  
A New Species

The genus Systenus Loew, 1857 is recorded from Afrotropical Region for the first time. A description of a new species, Systenus africanus Grichanov sp. nov., and notes on females of another probably new Afrotropical species are provided. The genus is considered now as cosmopolitan. A key to species and species groups of the Systenus worldwide is compiled.

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