Large-flowered Beardtongue (Penstemon grandiflorus)

Large-flowered beardtongue is one of the largest species in the genus Penstemon. It grows in grasslands throughout the Great Plains, but its habitat is much reduced due to agriculture and developement. What remains is increasingly threatened by weeds. The yellow flower in this photo is leafy spurge, which was introduced from Europe and is one of the worst weeds in North America. Photo is from the Sheyenne National Grasslands in North Dakota.