Stellaria Longipes Research Articles

Studies on the Stellaria longipes complex (Caryophyllaceae): relationships among the species based on seed protein profiles

CHINNAPPA, C. C, GIFFORD, D. J. & RAMAMORRTHY, J., 1992. Studies on the Stellaria longipes complex (Caryophyllaceae): relationships among the species based on seed protein profiles. The protein profiles of nine genera of the family Caryophyllaceae show distinct patterns. Within the genus Stellaria, six species were studied. The four North American species show more or less similar profiles, while the two European species have quite different patterns. There are some indications to suggest that the polyploid species, 5. longipes, is closely related to diploid S. longifolia and S. porsildii. The seed protein profiles of these species support the view that 5. longipes might have originated from hybridization between the two diploid species.

Natural hybridization between Stellaria longipes and Stellaria borealis (Caryophyllaceae)

Multivariate principal components analyses of seven morphological characters of a putative hybrid population (located at Plateau Mountain, Kananaskis, Alberta) indicated the occurrence of hybridization between Stellaria longipes and Stellaria borealis. Although the putative hybrid population had intermediate morphology between the two species, it clustered closer to that of S. longipes. Electrophoretic analysis of 15 isozyme loci confirmed that the putative hybrid population was a result of hybridization and possibly introgression. Unique alleles of both species were present in the hybrid, although they were more often attributable to S. longipes. The genetic identity and the level of genetic variability of the hybrid was of an intermediate level between the two species, but closer to that of S. longipes. Key words: natural hybridization, Stellaria longipes, Stellaria borealis, introgression, isozymes.

POPULATION DIFFERENTIATION FOR PHENOTYPIC PLASTICITY IN THE STELLARIA LONGIPES COMPLEX

Population differentiation for phenotypic plasticity of 12 morphological and reproductive traits was investigated in five populations of the Stellaria longipes complex including a population of the sand dune endemic S. arenicola. Population differentiation was detected for the mean (genotypic) value, amount of plasticity, and pattern of plasticity of traits. Average amount of plasticity was not related to degree of isozyme variability in the populations. Differentiation for pattern of plasticity was much more common than for amount. The direction and extent of divergence among populations was dependent on which of the three trait aspects was under consideration (mean, amount of plasticity, pattern of plasticity) and did not reflect their similarity as revealed by enzyme electrophoretic data. It was concluded that trait means, amounts of plasticity, and patterns of plasticity are independent of one another during evolutionary divergence and may be influenced by mosaic selection.

Population Differentiation for Phenotypic Plasticity in the Stellaria longipes Complex

Population Differentiation for Phenotypic Plasticity in the Stellaria longipes Complex

Evolution of Phenotypic Plasticity in the Stellaria longipes Complex: Comparisons Among Cytotypes and Habitats

Evolution of Phenotypic Plasticity in the Stellaria longipes Complex: Comparisons Among Cytotypes and Habitats

Patterns of Variation in the Stellaria longipes Complex: Effects of Polyploidy and Natural Selection

Patterns of Variation in the Stellaria longipes Complex: Effects of Polyploidy and Natural Selection

Population differentiation of the Stellaria longipes complex within Saskatchewan's Athabasca sand dunes

Stellaria arenicola, a recent derivative within the S. longipes complex, is an endemic of the Athabasca sand dunes. Analysis of 11 morphological characters on 40 genets showed that both the endemic and parental (S. longipes) species are present within the Thomson Bay dune field and that the two forms are distinct. Individuals of S. arenicola were distinguished by only a few characters, typically, large yellow capsules with reflexed teeth and yellowish leaf and stem pigmentation. The endemic also exhibited a higher sexual reproductive output. Many characteristics of vegetative morphology showed plasticity in both species, but the two remained distinct when grown in a common garden. On the sand dunes S. longipes is restricted to beach dunes bordering Lake Athabasca while S. arenicola is predominant on the active dune field inland. The two dune systems represented environmentally distinct microhabitats. The active inner dunes were characterized by an unstable, fine sand substrate and intense insolation. Field reciprocal transplants showed S. longipes was selected against in the inner dune habitat, while S. arenicola performed relatively well on the beach. Stellaria arenicola possibly arose in the active sand dune habitat as a result of selection pressure and genetic isolation.

Vegetation colonizing the bed of a recently drained thermokarst lake (Illisarvik), Northwest Territories

Illisarvik is the site of a thermokarst lake that was artificially drained in August 1978. The lake bed is now dry in most areas and wind erosion is extensive. The surface material is either sandy peat or organic lake mud, except along the eastern margin, where it is sandy. Substrate type appears to have had little influence on distributional patterns of the colonizing vegetation. More important factors are probably erosion, surface wetness, and proximity of the lake-bed margin. Common on the lake bed are Puccinellia borealis and Arctagrostis latifolia. Other widespread species include Senecio congestus, Carex aquatilis, Descurainia sophioides, Matricaria ambigua, Artemisia tilesii, Arctophila fulva, and Stellaria longipes. Senecio and Arctophila form dense stands around the two small residual ponds. Eroded surfaces have a very scant cover of Descurainia seedlings and Puccinellia tussocks. Many elements of Illisarvik's flora are common to other recently disturbed sites near the Arctic coast of northwestern North America.

Studies on the Stellaria longipes complex: phenotypic plasticity. I. Response of stem elongation to temperature and photoperiod

Clonal material of one genotype of Stellaria longipes Goldie s.l. was used to study the effects of photoperiod and temperature on stem elongation. Temperature is the more important influence for induction of stem elongation. Photoperiod exerts a lesser effect. A combined synergistic effect of temperature and photoperiod is in operation. A minimum number of heat degree-days, equivalent to about 3 days at 22:18 °C (day: night) temperature, is required to induce elongation. A minimum period of "winter cold," equal to 50 short, cold days is required for maximum elongation in subsequent warm, long days. Some elongation will occur in continuous long, warm days, but a short cold period is essential for flowering. After 8 months in short, cold days flowering will occur without elongation.

The alpine flora of Teresa Island, Atlin Lake, B.C., with notes on its distribution

A comprehensive inventory of the vascular plants is provided for the alpine zone of Teresa Island in Atlin Provincial Park, British Columbia. A total of 161 taxa were identified from collections made during a research program conducted in the summers of 1974, 1975, and 1976. Of these taxa Arnica louiseana var. frigida, Draba lactea, Lupinus kuschei, Oxytropis huddelsonii, Poa lettermanii, Senecio sheldonensis, Senecio yukonensis, and Stellaria longipes var. edwardsii have a restricted or otherwise interesting distribution in British Columbia.Preliminary observations indicate that the local distribution of all the taxa is controlled by three environmental gradients: snow duration, moisture, and topography. Five different alpine habitat types are recognized as a result of different combinations of these gradients. These habitat types are (1) fell-fields and boulder fields, (2) meadows and shrub fields, (3) snow beds, (4) seepage sites, and (5) drainage areas. The habitat types and relative abundance of each taxon are listed.