Montana Field Guide

PLANTS: A tall hemi-parasitic, herbaceous perennial that arises from a branched caudex. Plants grow 15-50 cm tall, are sometimes branched from the base, and are glabrous or with short hairs (puberulent). This plant is notable among the paintbrushes for its diffuse ‘open’ form.

LEAVES: Arranged alternately on the stem. Leaves 2–6 cm long, linear to linear-lanceolate in shape, entire or upper leaves sometimes will have a pair of linear lobes. Leaves may be glabrous or puberulent.

INFLORESCENCE: A dense, terminal, bracteate spike with villous to tomentose hairs. The inflorescence tends to be less than 10 cm long while in flower, but elongates as fruits develop. Bracts become colorful, red to orange. The lobes of the floral bracts tend to be narrow, with two long lateral lobes arising from the lower portion of the central lobe. The long calyx (18-28 mm) is unequally lobed. The bottom half is deeply lobed (10-19 mm) while the upper is lobed less (2-8 mm), and together the two lobes tend to curve strongly upwards. Thus, the primary clefts of the calyx are much deeper adjacent to the lip of the corolla. The ultimate calyx lobes are 1-3 mm long and acute. The very long corolla (24-40 mm) is divided almost equally into two parts. The lower tubular portion is about 12-20 mm long, while the narrow hooded upper portion (galea) is about 10-24 long. the lower lip is about 1-2 mm long. The corolla exceeds the calyx and tends to almost lean downwards out of the cleft between the lower calyx lobes.

Sources: Giblin et al. [eds.] 2018; Holmgren in Intermountain Flora 1984.

Castilleja is a difficult genus because hybridization and allopolyploid speciation (containment of multiple sets of chromosomes that are derived from different species) fuzz a species’ characteristics (Giblin et al. [eds.] 2018).

To identify Castilleja species, it is important to (Giblin et al. [eds.] 2018):
* note colors of the bract, calyx, and corolla while in the field, and
* press many bracts, calyces, and corollas separately to show their shapes.

Castilleja linariifolia and Castilleja crista-galli can be mistaken for one another. It is speculated that Castilleja crista-galli is a hybrid product of Castilleja linariifolia x Castilleja miniata, because it can exhibit intermediate morphology. Studies are needed.

Wyoming Indian Paintbrush – Castilleja linariifolia, native:
* Inflorescence bracts yellow to orange.
* Flowers become more widely separated at maturity (than does C. crista-galli)
* Calyx is conspicuously more deeply cleft on the side adjacent to the corolla lip than on the back. Calyx is curved back.
* Calyx lobes are acute.

Greater Red Indian Paintbrush – Castilleja crista-galli, native:
* Inflorescence bracts are bright red.
* Primary calyx lobes are cleft deeper in front than in the back.
* Calyx lobes are acute to acuminate.

Grasslands, sagebrush steppe, talus slopes, and coniferous woodlands in the montane zones of Montana (Lesica et al. 2012).

POLLINATORS
The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus appositus, Bombus bifarius, Bombus fervidus, Bombus flavifrons, Bombus melanopygus, Bombus sylvicola, Bombus occidentalis, and Bombus kirbiellus (Macior 1974, Thorp et al. 1983, Bauer 1983, Mayer et al. 2000, Wilson et al. 2010, Pyke et al. 2012, Koch et al. 2012, Miller-Struttmann and Galen 2014, Williams et al. 2014).