Oxybaphus (Mirabilis) hirsutus - Umbrellawort - Four-O'Clock Family (Nyctaginaceae) - Summer and Late - Colorado Wildflower - Stems of Heartleaf Four-o'clock are also predominantly hairless. Some references suggest that M. hirsuta and M. nyctaginea might hybridize. Compare to Narrowleaf Four-o'clock (Mirabilis linearis), which has narrow, linear leaves.
Scutellaria brittonii - Skullcap - Mint Family (Lamiaceae) - Summer - Colorado Wildflowers - Is found in openings in dry pine forests and on dry open slopes. Pairs of flowers are attached at the nodes of the stem. Plants grow to a height of 4" - 8".
Padus (Prunus) virginiana - Chokecherry - Rose Family (Roseaceae) - Early and Summer - Colorado Shrub - "Padus" the ancient Greek name for this plant. "Virginiana" is a common specific epithet given to honor the place the plant was first collected. (Other states, territories, or rivers are also the source of plant names: "Canadensis", "Missouriensis", "Arizonica".... The colony/state of "Virginia" derives its name from the "Virgin Queen", Queen Elizabeth the First of England.)
Tithymalus brachycera - Rocky Mountain spurge (Horned spurge) - Spurge Family (Euphorbiaceae) - Summer - Colorado Wildflower - "Tithymalus" is an "ancient Greek name for a plant with milky sap (Weber)". "Brachy cera" is Greek for "short horned". In 1753 Linnaeus named the genus "Euphorbia", most probably, according to Intermountain Flora, for "Euphorbus, physician of King Juba of Numidia, an ancient kingdom of North Africa.
Thermopsis divaricarpa - Golden banner - Pea Family (Fabaceae) - Early and Summer - Colorado Wildflower - The species are identified by the shape of their seed pods. T. rhombifolia has strongly curved pods and T. montana has straight, erect pods. Some sources consider all three to be varieties of a single species. Weber describes T. divaricarpa as having glabrous seed pods, but the pods in the photo are strongly pubescent, suggesting this might not be a good identifying characteristic.