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Population genetic structure was analyzed in the rare, native prairie legume Lespedeza leptostachya Engelm. and in the widespread L. capitata Michx. Both species produce a mixture of chasmogamous and cleistogamous flowers. Allozymes were analyzed for 32 loci from 224 individuals from 12 populations of L. leptostachya and for 34 loci in 291 individuals from 12 populations of L. capitata. L. leptostachya is entirely monomorphic at all loci studied, while L. capitata shows strong among‐population differentiation for the limited variation that occurs in that species. Allozyme data suggest that the level of gene flow among populations of L. capitata is very low, and that very low levels of outcrossing are effected by the chasmogamous flowers in L. capitata.

Detention ponds and constructed wetlands have proven to be effective in reducing peak stormwater runoff volume and flow, and recent interest has extended to utilizing them to improve stormwater runoff quality. A review of stormwater runoff studies indicated that lead, zinc, copper, cadmium, phosphorus, and chloride are contaminants of primary concern. In laboratory settings, the uptake of contaminants by three wetland plant species, Glyceria grandis, Scirpus validus, and Spartina pectinata, was examined and removal rates from nutrient solutions inflow and nonflow reactors were measured. The removal rates varied by plant species and target contaminant, and no one species was the best accumulator of all six contaminants. Belowground tissues of all three species accumulated higher concentrations of the four heavy metals and aboveground tissues accumulated higher concentrations of phosphorus and chloride. Plants grown in flow reactors showed significantly higher accumulation rates than those grown in nonflow reactors. Also, plants grown hydroponically accumulated higher concentrations of the six target contaminants than those grown in sand reactors. However, those grown in sand had a much greater increase of biomass and removed a greater mass of the six target contaminants. Removal rates measured in these experiments can be used to design detention ponds to maximize stormwater remediation.

ABSTRACT. Scientists and students from five countries combined research and education in an investigation of bioclimatic zonation along a Canadian Arctic transect, from Amund Ringnes Island and Ellesmere Island in the north to the Daring Lake research camp at the southern edge of the tundra in Nunavut. We addressed three important needs in Arctic science: 1) to integrate education and research, 2) to provide field experiences for undergraduates, and 3) to foster international collaboration. We describe five subzones within the Arctic tundra zone. Subzones are defined by the vegetation typical of mesic environments at low elevations and the dominant growth forms of vegetation in these environments. Subzonal boundaries coincide with the northern limits of several species of woody plants with distinct upright or prostrate growth forms, and ultimately with the northern limit of woody plant species. The five subzones, A-E, from north to south, are characterized by dominant growth form: (A) cushion forb, (B) prostrate dwarf shrub, (C) hemiprostrate dwarf shrub, (D) erect dwarf shrub, and (E) low shrub.

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