Natural intersectional hybridization between North American species of Populus (Salicaceae) in sections Aigeiros and Tacamahaca. II. Taxonomy

1984 ◽  
Vol 62 (2) ◽  
pp. 325-335 ◽  
Author(s):  
James E. Eckenwalder
Keyword(s):  
North American ◽  
Native Species ◽  
Natural Populations ◽  
North American Species ◽  
Shade Trees ◽  
Apparent Absence ◽  
Native North American ◽  
Natural Hybrids ◽  
Chromatographic Profile ◽  
Putative Hybrids

Five of six possible hybrid combinations of the two native North American species of Populus sect. Aigeiros Duby with the three native species of sect. Tacamahaca Spach have been found in nature. Putative hybrids occur wherever species of the two sections are sympatric and sometimes even beyond the range of one or both parents. Parents of the sixth possible combination are not, however, sympatric and this explains the apparent absence of the corresponding hybrid. Although the five hybrids can easily be recognized as a group, each parentage yields hybrids of unique morphology, all of which have previously been provided with binomials. Variability within each hybrid reflects variation in its parents. These hybrids are morphologically intermediate between their putative parents and have an additive chromatographic profile combining leaf flavonoids of each pair. Trees of P. × generosa (P. deltoides × P. trichocarpa) and P. × jackii (P. deltoides × P. balsamifera) from natural populations closely resemble artificial hybrids between their presumed parents. Three natural hybrids, P. × acuminata (P. deltoides × P. anguslifolia), P. × jackii, and P. × parryi (P. fremontii × P. trichocarpa), are all cultivated as shade trees. Keys distinguish the five hybrids from each other and from their parents; each hybrid is described; its nomenclature is clarified; and its range is mapped in relation to those of its parents.

scholarly journals Crayfish plague affects juvenile survival and adult behaviour of invasive signal crayfish

Parasitology ◽  
2020 ◽  
Vol 147 (6) ◽  
pp. 706-714 ◽  
Author(s):  
John Rhidian Thomas ◽  
Chloe V. Robinson ◽  
Agata Mrugała ◽  
Amy R. Ellison ◽  
Emily Matthews ◽  
...  
Keyword(s):  
North American ◽  
Native Species ◽  
North American Species ◽  
Juvenile Survival ◽  
Signal Crayfish ◽  
Aphanomyces Astaci ◽  
The North ◽  
High Infection ◽  
Oomycete Pathogen ◽  
The Impact

AbstractThe spread of invasive, non-native species is a key threat to biodiversity. Parasites can play a significant role by influencing their invasive host's survival or behaviour, which can subsequently alter invasion dynamics. The North American signal crayfish (Pacifastacus leniusculus) is a known carrier of Aphanomyces astaci, an oomycete pathogen that is the causative agent of crayfish plague and fatal to European crayfish species, whereas North American species are considered to be largely resistant. There is some evidence, however, that North American species, can also succumb to crayfish plague, though how A. astaci affects such ‘reservoir hosts’ is rarely considered. Here, we tested the impact of A. astaci infection on signal crayfish, by assessing juvenile survival and adult behaviour following exposure to A. astaci zoospores. Juvenile signal crayfish suffered high mortality 4-weeks post-hatching, but not as older juveniles. Furthermore, adult signal crayfish with high-infection levels displayed altered behaviours, being less likely to leave the water, explore terrestrial areas and exhibit escape responses. Overall, we reveal that A. astaci infection affects signal crayfish to a much greater extent than previously considered, which may not only have direct consequences for invasions, but could substantially affect commercially harvested signal crayfish stocks worldwide.

TWO PANDEMIS SPECIES INTRODUCED INTO BRITISH COLUMBIA, WITH A COMPARISON OF NATIVE NORTH AMERICAN SPECIES (LEPIDOPTERA: TORTRICIDAE)

1980 ◽  
Vol 112 (6) ◽  
pp. 549-554 ◽  
Author(s):  
Akira Mutuura
Keyword(s):  
British Columbia ◽  
North American ◽  
North American Species ◽  
Native North American ◽  
Pandemis Pyrusana

AbstractTwo Pandemis species, introduced into British Columbia, are discussed: P. cerasana (Hübner) found in 1965 and P. heparana (Denis & Schiffermüller) found in 1978. They are compared with the native North American Pandemis pyrusana Kearfott and P. limitata (Robinson).

Relationships among native and introduced North American species of Hordeum, based on chloroplast DNA restriction-site variation

1991 ◽  
Vol 69 (11) ◽  
pp. 2421-2426 ◽  
Author(s):  
Bernard R. Baum ◽  
L. Grant Bailey
Keyword(s):  
Chloroplast Dna ◽  
North American ◽  
Native Species ◽  
Restriction Site ◽  
North American Species ◽  
Central Position ◽  
Site Analysis ◽  
Site Variation ◽  
Dna Restriction ◽  
Cladistic Analyses

Restriction-site analysis of chloroplast DNA was carried out on a total of 13 North American species of Hordeum, 7 native and 6 introduced. Sites associated with polymorphic banding patterns were omitted so that only invariant sites within species were used in the analyses. A number of taxa whose species status is in dispute can indeed be supported at species rank, i.e., H. brachyantherum, H. californicum, H. pusillum, H. intercedens, H. marinum, and H. geniculatum. The maternal progenitor of H. arizonicum is H. pusillum, and this is further discussed in light of other possibilities. Both phenetic and cladistic analyses indicate a tripartite relationship whereby H. vulgare is distant from the group of H. leporinum, H. glaucum, and H. murinum and from a second group comprising the native species H. brachyantherum, H. californicum, H. arizonicum, H. jubatum, H. pusillum, H. intercedens, and H. depressum. Hordeum marinum and H. geniculatum occupy a central position in this relationship. Speculation that the putative ancient form of Hordeum resembled a H. murinum – H. geniculatum-like species is discussed. Key words: chloroplast DNA, Hordeum, phylogenetic relationships.

scholarly journals Admixture between native and invasive populations may increase invasiveness of Mimulus guttatus

2015 ◽  
Vol 282 (1815) ◽  
pp. 20151487 ◽  
Author(s):  
Mark van Kleunen ◽  
Michael Röckle ◽  
Marc Stift
Keyword(s):  
Invasive Species ◽  
Biomass Production ◽  
Invasive Plants ◽  
North American ◽  
Native Species ◽  
Mimulus Guttatus ◽  
Native North American ◽  
Fitness Consequences ◽  
Self Fertilization ◽  
Different Populations

Self-fertilization and admixture of genotypes from different populations can have major fitness consequences in native species. However, few studies have addressed their potential roles in invasive species. Here, we used plants of Mimulus guttatus from seven native North American, three invasive Scottish and four invasive New Zealand populations to address this. We created seeds from self-fertilization, within-population outcrossing, between-population outcrossing within the same range, and outcrossing between the native and invasive ranges. A greenhouse experiment showed that native and invasive plants of M. guttatus suffered to similar degrees from inbreeding depression, in terms of asexual reproduction and biomass production. After outcrossing with plants from other populations, M. guttatus benefited from heterosis, in terms of asexual and sexual reproduction, and biomass production, particularly when plants from native and invasive populations were crossed. This suggests that, when novel genotypes of M. guttatus from the native North American range will be introduced to the invasive ranges, subsequent outcrossing with M. guttatus plants that are already there might further boost invasiveness of this species.

Evolutionary and physiological adaptations of aquatic invasive animals: r selection versus resistance

2002 ◽  
Vol 59 (7) ◽  
pp. 1235-1244 ◽  
Author(s):  
Robert F McMahon
Keyword(s):  
North American ◽  
Dreissena Polymorpha ◽  
Native Species ◽  
Population Recovery ◽  
Early Maturity ◽  
Physiological Tolerance ◽  
Native North American ◽  
Adaptive Value ◽  
Physiological Adaptations ◽  
Environmental Extremes

Invasive species have been characterized as tolerant of environmental extremes. This hypothesis was evaluated for invasive aquatic species in North America, particularly Asian clams, Corbicula fluminea, and zebra mussels, Dreissena polymorpha. Both species have rapid growth, early maturity, short life spans, and elevated fecundity, allowing rapid population recovery after reductions by rarefractive, environmental extremes. Extensive resistance capacities offer little adaptive value to invasive, r-selected species, because population reductions occur in their unstable habitats regardless of degree of stress tolerance. Thus, both species have relatively poor physiologic resistance, depending instead on elevated growth and fecundity for rapid population recovery. In contrast, native North American bivalve species are often adapted to stable habitats where perturbation is infrequent (i.e., freshwater unionoidean bivalves). They are characterized by slow growth, extended life spans, and low effective fecundities, slowing population recoveries (K-selected), and have evolved extensive resistance adaptations to avoid extirpation during environmental extremes. Review of resistance adaptations in other North American aquatic invaders revealed poorer or equivalent physiological tolerance relative to taxonomically related native species, suggesting that extensive physiological tolerance is not required for invasive success.

Biosystematic studies in the North American species of Linum, section Adenolinum (Linaceae)

1971 ◽  
Vol 49 (8) ◽  
pp. 1379-1388 ◽  
Author(s):  
Theodore Mosquin
Keyword(s):  
North American ◽  
Morphological Evolution ◽  
North American Species ◽  
Evolutionary Trends ◽  
Isolated Populations ◽  
Life Habit ◽  
Good Pollen ◽  
The North ◽  
Native North American ◽  
Variation Patterns

Variation patterns and interpopulational relationships were examined in Linum lewisii Pursh and L. pratense (Norton) Small, the two native North American blue-flowered flax species. The two principal evolutionary trends in the North American populations have been toward self-pollination and an annual life habit. A third trend, toward greater outcrossing, is considered probable. Hybridizations between and within species indicate that evolution has occurred mainly by the accumulation of small genic changes in geographically isolated populations. The buildup of sterility barriers between populations regardless of species has not been extensive and in no case do hybrids have less than 30% good pollen. In general, morphological evolution has occurred independently of the buildup of sterility barriers. A new taxonomic combination, L. lewisii ssp. lepagei (Boivin) Mosquin, is adopted.

scholarly journals THE NORTH AMERICAN SPECIES OF ORPHULELLA

1899 ◽  
Vol 31 (7) ◽  
pp. 177-188
Author(s):  
Samuel H. Scudder
Keyword(s):  
United States ◽  
North American ◽  
Native Species ◽  
The United States ◽  
North American Species ◽  
South American ◽  
The South ◽  
The North

By the kindness of Prof. L. Bruner I have recently been able to study specimens of the South American Orphula pagana Stal., the type of the genus, and so to compare its structure with that of our native species latterly referred to Orphula. By this it appears, as Mr. Bruner has pointed out to me in correspondence, and as Mr. A. P. Morse has suggested (Psyche, VII., 407), that our species should be referred rathar to Orphulella, separated by Giglio-Tos from Orphula in 1894, though this was afterwards regarded by him as having only a subgeneric value Orphula in the stricter sense of the term is not, so far as I know, represented in the United States. Orphulella is the most widely distributed genus of North American Trypalinae and the most abundant in species. Those known to Prof. J. McNeill in his recent revision of our Tryxalinae were well separated by a table which I have here made the basis of a new one to include a considerable number of new forms. Besides describing these, I have added notes of distribution of the others, based on the collections in my hands, and given their principal synonymy.

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