Revision of the Aster lanceolatus complex, including A. simplex and A. hesperius (Compositae: Astereae): a multivariate morphometric study

1987 ◽  
Vol 65 (5) ◽  
pp. 1047-1062 ◽  
Author(s):  
John C. Semple ◽  
Jerry G. Chmielewski
Keyword(s):  
North America ◽  
Morphological Variation ◽  
Multivariate Analyses ◽  
Single Species ◽  
Morphometric Study ◽  
Eastern North America ◽  
Western North America ◽  
Reproductive Structures ◽  
Infraspecific Taxa ◽  
Typical Variety

The complex is treated as a single species, Aster lanceolatus, on the basis of fieldwork, garden studies, herbarium work, and multivariate analyses of morphological variation of reproductive structures among 200 representative specimens. Two subspecies are recognized: ssp. hesperius occurring in western North America and ssp. lanceolatus occurring in central and eastern North America. Subspecies lanceolatus is further divided into four varieties: var. hirsuticaulis, var. interior, var. lanceolatus (including A. simplex), and var. latifolius. The typical variety is the most diverse and is considered to include forms most like the ancestor of the species. A key to the five infraspecific taxa is presented along with full synonymy. The following new names and combinations are proposed: Aster lanceolatus ssp. hesperius, A. lanceolatus ssp. lanceolatus var. hirsuticaulis, A. lanceolatus ssp. lanceolatus var. interior, and A. lanceolatus ssp. lanceolatus var. latifolius.

High-Frequency Seismic Wave Propagation in Northeastern North America

1990 ◽  
Vol 61 (3-4) ◽  
pp. 193-208 ◽  
Author(s):  
S. E. Hough ◽  
K. H. Jacob ◽  
L. Seeber
Keyword(s):  
North America ◽  
High Frequency ◽  
Characteristic Length ◽  
Body Waves ◽  
Eastern North America ◽  
Western North America ◽  
Energy Propagation ◽  
Length Scales ◽  
Near Surface ◽  
High Frequencies

Abstract A key element in the assessment of seismic hazard is the estimation of how energy propagation from a given earthquake is affected by crustal structure near the receiver and along the more distant propagation path. In this paper, we present data from a variety of sources in eastern North America recorded at epicentral distances of a few to 800 km, and characterize and interpret systematic features. Site effects have been classically considered in terms of amplification either within a sediment-filled valley or from a single topographic feature (Geli et al., 1988). We present evidence of high frequency (5–30 Hz) resonances observed in hard-rock recordings of both body waves and Lg waves, and suggest that site effect should be expanded regionally to include structural and topographic information over sufficiently large areas to include several wavelengths of any features that may interact with seismic waves in the frequency range of interest. A growing body of evidence suggests that ground motions at high frequencies recorded at large epicentral distances in eastern North America are controlled by resonance effects. We hypothesize that a fundamental difference between eastern and western North America spectra stems from a combination of differences in the character of topography and near-surface structure. Active tectonics of western North America gives rise to a complex crust that scatters seismic energy in a random manner and results in very effective attenuation of high frequencies. The older eastern North American crust contains scatterers that are more ordered, with characteristic length scales that give rise to resonance phenomena in the frequency band critical for earthquake hazard. We present preliminary analysis of topographic data from the Adirondack Mountains in New York that demonstrates the existence of characteristic length scales on the order of up to 1–3 kilometers. Features with these length scales will effectively scatter energy at frequencies in the 1 to 10 Hz range.

REVISION OF SOME DIMERIELLA AND DIMEROSPORIUM PARASITES OF CONIFERS

1965 ◽  
Vol 43 (6) ◽  
pp. 631-639 ◽  
Author(s):  
R. A. Shoemaker
Keyword(s):  
North America ◽  
Abies Alba ◽  
Tsuga Canadensis ◽  
Tsuga Heterophylla ◽  
Eastern North America ◽  
Western North America ◽  
Abies Grandis ◽  
Abies Amabilis ◽  
Conifer Needles ◽  
Tsuga Mertensiana

Study of the type of Dimerosporium balsamicola (Peck) Ell. & Ev. (≡ Meliola balsamicola Peck) revealed that this species is a melioline hyperparasite. The fungus is transferred to Dimerium, redescribed, illustrated, and distinguished from Phacocryptopus nudus (Peck) Petrak, Asterina sp., and from Epipolaeum abietis (Dearness) n. comb. (≡ Dimerosporium abietis Dearness), which also occur on Abies in North America. In all, four species of Epipolaeum that occur on conifer needles are treated: Epipolaeum abietis on Abies grandis (Dougl.) Lindl. and Abies amabilis (Dougl.) Forb. in western North America, on Abies alba Mill. in France, and on Keteleeria davidiana Beiss. in Formosa; Epipolaeum tsugae (Dearness) n. comb. on Tsuga canadensis (L.) Carr. in eastern North America, and on Tsuga heterophylla (Raf.) Sarg. and Tsuga mertensiana (Bong.) Carr. in western North America; Epipolaeum pseudotsugae (V. M. Miller & Bonar) n. comb. on Pseudotsuga taxifolia (Poir.) Britton from western North America; Epipolaeum terrieri (Petrak in Terrier) n. comb. on Abies alba in Switzerland.

A morphometric study of geographic variation in the snowshoe hare (Lepus americanus)

1985 ◽  
Vol 63 (3) ◽  
pp. 567-579 ◽  
Author(s):  
David W. Nagorsen
Keyword(s):  
North America ◽  
Great Lakes ◽  
Geographic Variation ◽  
Principal Component ◽  
Lepus Americanus ◽  
Morphometric Study ◽  
Western North America ◽  
Environmental Selection ◽  
Local Selection ◽  
Central Canada

Geographic variation in Lepus americanus was studied by multivariate analyses of 15 cranial measurements. A total of 1494 specimens from the entire geographic range were grouped into 37 geographic samples of males and females. Principal component analyses demonstrated that hares are largest in eastern North America, Alaska, and northwestern Canada, and smallest in the Pacific Northwest. Size clines exist in the Appalachian Mountains and western North America but size is relatively uniform throughout central Canada and the Great Lakes. A multiple regression of size with 16 climatic variables factors demonstrated that size and climate are strongly correlated; the size trends may reflect environmental selection. The differentiation of hares from the western Cordillera and Pacific coast, the similarity of populations from central Canada and the Great Lakes, and the clines in the Appalachians and western North America were evident in discriminant analyses. These patterns of variation among populations can be attributed to both gene flow and local selection. There is no evidence from the morphometric analyses for classifying populations into the 15 subspecies currently recognized.

The Galium trifidum group (Galium sect. Aparinoides, Rubiaceae)

1976 ◽  
Vol 54 (16) ◽  
pp. 1911-1925 ◽  
Author(s):  
C. Puff
Keyword(s):  
North America ◽  
Eastern North America ◽  
Great Lakes Region ◽  
Western North America ◽  
Eastern Asia ◽  
Chromosome Counts ◽  
New Classification ◽  
North Eastern ◽  
North Western

By using morphology, karyology, pollen size, leaf flavonoids, ecological observations, and modification experiments, a new classification of the Galium trifidum group is proposed. Nine taxa in five species are recognized: (1) G. tinctorium, with ssp. tinctorium and sap. floridanum (new comb.) in eastern North America; (2) G. brevipes, a rare species centered in the Great Lakes region; (3) G. trifidum, with ssp. trifidum in northern North America. Asia, and Europe, ssp. columbianum (new comb.) in (north)western North America and (north)eastern Asia, and ssp. subbiflorum (new comb.) and ssp. halophilum (new comb.) in northern North America; (4) G. innocuum in southeastern Asia; (5) G. karakulense in central Asia.New chromosome counts of n = 12 and 2n = 24 are reported for G. tinctorium ssp. tinctorium and ssp. floridanum; and G. trifidum ssp. trifidum, ssp. columbianum, and ssp. subbiflorum.

A late snow bed bryophyte community in western Newfoundland, Canada

1983 ◽  
Vol 61 (1) ◽  
pp. 218-223 ◽  
Author(s):  
René J. Belland
Keyword(s):  
North America ◽  
Distribution Pattern ◽  
Disjunct Distribution ◽  
Eastern North America ◽  
Western North America ◽  
Undescribed Species ◽  
Additional Species

The bryophyte floras of eight bryophyte-dominated late snow beds near Bonne Bay, western Newfoundland, were investigated and consisted of 49 species of which 4 are reported new for eastern North America (excluding Greenland): Andreaea nivalis Hook., Kiaeria falcata (Hedw.) Hag., Moerckia blyttii (Moerck) Brockm., and an undescribed species of Trematodon. Five additional species were previously unreported from Newfoundland. Eleven bryophytes from the Newfoundland snow beds are characteristic of this habitat throughout much of their world range, and 13 species show a disjunct distribution pattern between eastern and western North America.

scholarly journals Redescription of Arundel formation Ornithomimosaur material and a reinterpretation of Nedcolbertia justinhofmanni as an “Ostrich Dinosaur”: Biogeographic implications

2016 ◽  
Author(s):  
Chase Doran Brownstein
Keyword(s):  
United States ◽  
North America ◽  
Early Cretaceous ◽  
Fossil Record ◽  
East Coast ◽  
The United States ◽  
Eastern North America ◽  
New Taxon ◽  
Western North America ◽  
The Past

The fossil record of dinosaurs from the Early Cretaceous of eastern North America is scant, and only a few sediments to the east of the continent are fossiliferous. Among them is the Arundel Formation of the east coast of the United States, which has produced among the best dinosaur faunas known from the Early Cretaceous of eastern North America. The diverse dinosaur fauna of this formation has been thoroughly discussed previously, but few of the dinosaur species originally described from the Arundel are still regarded as valid genera. Much of the Arundel material is in need of review and redescription. Among the fossils of dinosaurs from this formation are those referred to ornithomimosaurs. Here, I redescribe ornithomimosaur remains from the Arundel Formation which may warrant the naming of a new taxon of dinosaur. These remains provide key information on the theropods of the Early Cretaceous of Eastern North America. The description of the Arundel material herein along with recent discoveries of basal ornithomimosaurs in the past 15 years has allowed for comparisons with the coelurosaur Nedcolbertia justinhofmanni, suggesting the latter animal was a basal ornithomimosaurian dinosaur rather than a “generalized” coelurosaur. Comparisons between the Arundel ornithomimosaur and similar southeast Asian ornithomimosaurian material as well as ornithomimosaur remains from western North America suggest that a lineage of ornithomimosaurs with a metatarsal condition intermediate between that of basal and derived ornithomimosaurs was present through southeast Asia into North America, in turn suggesting that such animals coexisted with genera having a more primitive metatarsal morphology as seen in N. justinhofmanni.

scholarly journals New records of theropods from the latest Cretaceous of New Jersey and the Maastrichtian Appalachian fauna

2019 ◽  
Vol 6 (11) ◽  
pp. 191206 ◽  
Author(s):  
Chase Doran Brownstein
Keyword(s):  
New Jersey ◽  
North America ◽  
Fossil Record ◽  
New Records ◽  
The Other ◽  
Eastern North America ◽  
Western North America ◽  
Northeastern North America ◽  
Terrestrial Vertebrate ◽  
Postcranial Remains

The faunal changes that occurred in the few million years before the Cretaceous–Palaeogene extinction are of much interest to vertebrate palaeontologists. Western North America preserves arguably the best fossil record from this time, whereas terrestrial vertebrate fossils from the eastern portion of the continent are usually limited to isolated, eroded postcranial remains. Examination of fragmentary specimens from the American east, which was isolated for the majority of the Cretaceous as the landmass Appalachia, is nonetheless important for better understanding dinosaur diversity at the end of the Mesozoic. Here, I report on two theropod teeth from the Mount Laurel Formation, a lower-middle Maastrichtian unit from northeastern North America. One of these preserves in detail the structure of the outer enamel and resembles the dentition of the tyrannosauroid Dryptosaurus aquilunguis among latest Cretaceous forms in being heavily mediolaterally compressed and showing many moderately developed enamel crenulations. Along with previously reported tyrannosauroid material from the Mt Laurel and overlying Cretaceous units, this fossil supports the presence of non-tyrannosaurid tyrannosauroids in the Campanian–Maastrichtian of eastern North America and provides evidence for the hypothesis that the area was still home to relictual vertebrates through the end of the Mesozoic. The other tooth is assignable to a dromaeosaurid and represents both the youngest occurrence of a non-avian maniraptoran in eastern North America and the first from the Maastrichtian reported east of the Mississippi. This tooth, which belonged to a 3–4 m dromaeosaurid based on size comparisons with the teeth of taxa for which skeletons are known, increases the diversity of the Maastrichtian dinosaur fauna of Appalachia. Along with previously reported dromaeosaurid teeth, the Mt Laurel specimen supports the presence of mid-sized to large dromaeosaurids in eastern North America throughout the Cretaceous.

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