Buller Pond, Kanaskis Country, Alberta, Canada
Canon EOS Rebel XTi; 18-200mm Lens

AKA White Thistle
A robust leafy native thistle which can grows to be almost two meters (6 feet) tall, with a stem of about 1/4-1/2 inch diameter. It favors riparian areas and floodplains, as well as many moist open fields, and subalpine areas in mountains. Prefers moist rocky sites and rich soils. It is our most common native thistle in the mountains.
Flowers:
White to ivory colored flowers, bunched together in heads about 2 inches across in axils of leaves without stalks (peduncles). Only with disc flowers. Sepals (pappus) of plumose bristles. Flowers subtended by involucral bracts that are narrow and cobweb-like. Few to many flower heads on upper part of stem.
Fruit:
Small hairless achenes connected to bristles, with feathery tops.
Leaves:
Long, entire to lobed, lance shaped, spiny, woolly leaves. Usually white with dense hairs on bottom surface. Leaves form basal rosette the first year and grow on the flowering stalk the second year
Habitat:
Floodplains, rocky soil, moist open fields, riparian areas, also common in subalpine meadows and other open areas in mountains where it is usually the most common thistle
Distribution:
Unique to northern rockies and Pacific Northwest. Occurs from BC south and east to Wyoming, especially in mountains

Thank you to http://nhguide.dbs.umt.edu (University of Montana Plant Guide)