About the Robert L. Jefferies Collection http://hdl.handle.net/10315/9274 2013-05-23T22:29:01Z 2013-05-23T22:29:01Z Wolff, S.L. Jefferies, Robert L. http://hdl.handle.net/10315/20775 2013-05-22T17:26:31Z 2013-03-01T00:00:00Z

Taxonomic status of diploid Salicornai europaea (s.L.) (Chenopodiaceae) in northeastern North America. Wolff, S.L.; Jefferies, Robert L. The taxonomic status of diploid Salicornia europaea L. (s.1.) in northeastern North America has been evaluated based on morphological and electrophoretic variation within and between populations. Populations of two European diploid micro- species, S. ramosissima J. Woods and S. europaea (s.s.), and populations of the midwestern diploid, S. rubra A. Nels., were also examined, affording a comparison between North American S. europaea (s.1.) and recognized species. Anther length, width of the scarious border of the fertile segment, and floral perianth shape were used to subdivide North American diploid populations into two groups. These groups were morphologically distinct from S. rubra and the European microspecies. The electrophoretic profile was unique in each morphologically distinct group of populations of S. europaea (s.1.) in northeastern North America. Based on morphological, geographical, and electrophoretic differences, diploid populations of S. europaea (s.1.) from this region are assigned to one of the following two new species: S. maririma Wolff & Jefferies, sp.nov., and S. borealis Wolff & Jefferies, sp.nov. The tetraploids are retained in S. europaea (s.1.).

2013-03-01T00:00:00Z Kotanen, Peter M. http://hdl.handle.net/10315/20729 2013-05-22T17:36:29Z 2013-02-21T00:00:00Z

Robert Jefferies with a baby Arctic Fox Kotanen, Peter M. Robert L. Jefferies with an Arctic fox cub, which was released unharmed - at least the fox was, it was rather nippy!

2013-02-21T00:00:00Z Kotanen, Peter M. http://hdl.handle.net/10315/20728 2013-05-22T18:04:03Z 2013-02-21T00:00:00Z

Researchers on the top of the McConnell esker Kotanen, Peter M. Researchers Robert Jefferies, Peter Kotanen, Dick Kerbes, Peter and Paul Mekiuniak, at the top of the esker of the McConnell River, which drains into the Hudson Bay at Kivalliq region in Nunavut territory.

2013-02-21T00:00:00Z Jefferies, Robert L. Jensen, A. Bazely, Dawn R. http://hdl.handle.net/10315/20556 2013-05-22T18:34:19Z 1983-01-01T00:00:00Z

The biology of the annual Salicornia europaea agg. At the limits of its range in Hudson Bay. Jefferies, Robert L.; Jensen, A.; Bazely, Dawn R. The biology of a marginal population of the annual Salicornia europaea agg. has been examined at La Perouse Bay, Manitoba, on the shores of Hudson Bay. Plants were confined to south-facing sites which became hypersaline in summer, but which were not covered by tides. The difference in temperature of surface sediments between south- and north-facing slopes was as much as 7°C. Although most seedlings emerged in June, germination continued throughout the summer, but plants that appeared late in the season failed to set seed. Mortality of both seedlings and adult plants was low. Seeds or seedlings from a south-facing slope were transplanted during a 2-year period within the same site, into another south-facing site, to a north-facing site, and to an intertidal site. Germination either failed to occur or else was poor at the latter two sites. In addition, seed production of mature plants was low compared with that for individuals transplanted within south-facing sites. Additions of nitrogen to north-facing slopes increased overall seed output per plant, but the ratio of unripened to ripened seeds remained the same as that in plants from untreated plots. The results are discussed in relation to the ecology of marginal populations.

1983-01-01T00:00:00Z