In the photographs below, you will see that Castilleja possesses showy "flowers." I put "flowers" in quotes because the showy structures are actually bracts, which are modified leaves. The corolla (petals) are actually inconspicuous and mostly greenish yellow, and are hidden beneath the large bracts. If you look closely, you'll be able to see the true flowers in some of the photographs below.
The first new paintbrush that we saw was in a prairie at Jewel Mountain near Boulder. The photograph above shows Orange Paintbrush (Castilleja integra). This species is known in the United States only from Texas, New Mexico, Arizona, and Colorado (USDA, NRCS 2010). Known also as Wholeleaf Indian Paintbrush, the leaves of this species are unlobed; in fact, the specific epithet integra means "whole" (Southwest Colorado Wildflowers 2010). Orange Paintbrush can be found growing in the plains, foothills, and montane life zones of Colorado, and is said to be the most common paintbrush in the plains of Colorado (Guennel 2004; Southwest Colorado Wildflowers 2010). The densely tomentose stem is a key feature used to identify this species (Weber 1976).
Along the road near Independence Pass, we stopped the car to photograph Scarlet Paintbrush (Castilleja miniata), also known as Giant Red Indian Painbrush. This species is known from the western United States, and from Canada east to Ontario (USDA, NRCS 2010). In Colorado, it grows in the foothills, montane, and subalpine life zones (Guennel 2004). This species is said to be the most common and variable member of the genus Castilleja in Colorado (Weber 1976).
My favorite paintbrush of our trip was Rosy Paintbrush (Castilleja rhexiifolia), shown above. This photograph was taken at Independence Pass. Also known as Splitleaf Indian Paintbrush, this species is known from states west of the Rocky Mountains (except California and Arizona), as well as from Brittish Columbia and Alberta (USDA, NRCS 2010). You can find this beautiful paintbrush with bracts of indescribable colors in the subalpine and alpine life zones of Colorado (Guennel 2004). This species, as well as others in the genus Castilleja, is well known for its propensity to hybridize with other members of the genus (Southwest Colorado Wildflowers 2010).
Also at Independence Pass, we saw one of the two whitish-bracted species of paintbrush that we saw on our trip, Western Paintbrush (Castilleja occidentalis). Western Paintbrush has a similar range to the preceding species, but is more confined to areas along the Rocky Mountains (USDA, NRCS 2010). This species grows in the subalpine and alpine life zones of Colorado (Guennel 2004), and is distinguished from the next species in part by its shorter height (up to 20 cm tall) (Weber 1976). Like other paintbrushes, this species is hemiparasitic, meaning that it sometimes obtains nutrients from the roots of nearby plants (Southwest Colorado Wildflowers 2010).
The other species of paintbrush that we saw with whitish bracts was Yellow Paintbrush (Castilleja sulphurea). This photograph was taken at Holy Cross Wilderness Area. Sulphur Indian Paintbrush, as it is also known, has a similar range to the two preceding species (USDA, NRCS 2010). It can be found in the plains, montane, and subalpine life zones of Colorado, and is distinguished from the previous species in part by its taller height (20 cm to 40 cm) (Weber 1976).
Now that I've seen approximatetly 3% of the known species of Castilleja, I can't wait to see the diversity and colorful bracts of the other 97%!
Guennel, G.K. (2004). Guide to Colorado Wildflowers, Volume 1: Plains and Foothills. Englewood, Colorado: Westcliffe Publishers.
Guennel, G.K. (2004). Guide to Colorado Wildflowers, Volume 2: Mountains. Englewood, Colorado: Westcliffe Publishers.
Southwest Colorado Wildflowers. Retrieved January 16, 2010. http://www.swcoloradowildflowers.com/.
USDA, NRCS. 2010. The PLANTS Database (http://plants.usda.gov/, 10 January 2010). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
Weber, W.A. (1976). Rocky Mountain Flora. Niwot, Colorado: University Press of Colorado