The large stems are bulrushes, a common water plant in the west that grows 5 or 6 feet tall. In this photo, the bulrush stems harmonize nicely with the other foliage growing in this marsh. This photo and several others on this website were taken from a low platform at Cave and Basin Marsh in Banff National Park, Alberta.
To reach the Cave and Basin area, drive south through downtown Banff, cross the Bow River bridge, and turn right on Cave Avenue. This site is 'Point of Interest Number 2' on this excellent Parks Canada map. Take time to visit the Cave and Basin historic area, and follow the signage down the hill to the marsh. There is also a nice hiking trail that loops around the entire marsh area.
