| Castilleja chromosa | |
|---|---|
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Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Lamiales |
| Family: | Orobanchaceae |
| Genus: | Castilleja |
| Species: | C. chromosa |
| Binomial name | |
| Castilleja chromosa | |
Castilleja chromosa, thedesert paintbrush, is a species offlowering plant in the familyOrobanchaceae found in the western United States. They are distributed indry scrub,steppe, anddesert. They have colorfulinflorescences which range from yellow to red in hue. This color is given not by the flowers, which are small, but by the colorfulbracts. The plants grow up to nearly half a meter (~1.5 ft) tall and are slightly bristly and greyish-green. Their stems do not branch, and their leaves are small andlance-shaped. Partialparasites, they steal some of their nutrients from neighboring plants.
The desert paintbrush, which blooms between May and September, has large, colorfulinflorescences between 2.5 and 15 centimeters (1 and 6 in) long and 1.5 to 5.5 cm (0.6 to 2.2 in) wide.[1] The inflorescence is alsohirsute to sometimespilose, covered in coarse hairs or covered in long soft hairs.[2] Thebracts are often confused with thepetals; the upper half of the bracts are orange or bright red, occasionally yellow, dull orange, or subdued pink. At their base they are more green or a muted purple,[1] but they are never purple towards their ends.[3] Each bract will usually be divided into three, five, or seven primary lobes;[2] however, they may occasionally lack divisions or have the lobes further divided into smaller secondary lobes.[1]
The actual flowers are yellowish-green with more or less reddish edges, tubular, and unremarkable.[4] The overall length is just 2.1 to 3.2 cm (0.8 to 1.3 in). The lower lip of the tube is reduced and dark green with incurving teeth, while the upper beak is more than half the total length of the flower.[3]
As flowering progresses and the seeds begin to develop, the inflorescence grows much longer.[2] The fruits measure between 1 and 1.5 centimeters (0.4 and 0.6 in) long and the seeds 2 mm (0.08 in). The seed surface has a wrinkled, net like appearance when ripe.[4]
The plants are gray-greenperennials that are at timessubshrubs, having partly woody stems especially towards their bases. Underground, they have a thicktaproot topped by a woodycaudex. They grow between 15 and 35 centimeters (0.5 and 1.1 ft) tall, though in good conditions they may reach 45 cm (1.5 ft).[1] Plants frequently have many straight to slightly curved, clustered stems that rarely branch higher up; they are more or less covered with bristly hairs.[2]
The leaves may be as little as 1.5 cm (0.6 in) in length or as long as 7 cm (2.8 in) but are more typically between 2.5 and 6 cm (1.0 and 2.4 in). They attachalternately to the stems and can belinear,lanceolate, oroblanceolate – narrow like a grass blade, shaped like a spear head, or a reversed spear head with the wider part past the midpoint. Like the bracts, they are divided into lobes – most often three or five, but sometimes as many as seven or lacking divisions altogether.[1]
Castilleja chromosa is classified in the genusCastilleja within the familyOrobanchaceae. Its scientific description and name was published byAven Nelson in 1899.[5] The desert paintbrush is similar to, and often confused with,Castilleja angustifolia.[3][6] It is known to form hybrids withCastilleja miniata.[7]
Castilleja chromosa has bothdiploid andtetraploid populations. In a 1977 study, no association was found with elevation, but diploid individuals were almost always found withArtemisia tridentata, big sagebrush.[7]
| Name | Year | Rank | Notes |
|---|---|---|---|
| Castilleja angustifolia var.collina(A.Nelson) Garrett | 1911 | variety | = het. |
| Castilleja collinaA.Nelson | 1901 | species | = het. |
| Castilleja eremophilaWooton & Standl. | 1913 | species | = het. |
| Castilleja ewaniiEastw. | 1941 | species | = het. |
| Castilleja helleriEdwin | 1959 | species | = het. |
| Castilleja martini subsp.ewanii(Eastw.) Munz | 1958 | subspecies | = het. |
| Castilleja martini var.ewanii(Eastw.) N.H.Holmgren | 1971 | variety | = het. |
| Castilleja miniata var.chromosa(A.Nelson) Garrett | 1911 | variety | ≡ hom. |
| Castilleja pyramidalisEdwin | 1959 | species | = het. |
| Notes: ≡homotypic synonym ; =heterotypic synonym | |||
The species namechromosa means "colorful", a reference to the bright colors of its bracts. In English, it is often known by thecommon namedesert paintbrush.[2] It is also known as thedesert Indian paintbrush –Indian in the context referring toIndigenous people.[8] It is also sometimes called thered desert paintbrush.[9]
The desert paintbrush is distributed across ten western US states.[5] In California, it largely grows east of theCascade Range, theSierra Nevada,San Bernardino Mountains, andSan Jacinto Mountains.[4] Likewise, it is largely native to eastern parts of Oregon with only a few reports of the species west of the Cascades. It grows in most of Idaho, but its exact distribution in Montana and Wyoming is not recorded by the USDA Natural Resources Conservation Service. It also has no exact locations recorded for Nevada, but grows in every county of Utah.[10] In Colorado, it grows largely west of theRocky Mountains.[9] Similarly, it grows in the northwestern quarter of New Mexico and all but the southernmost counties of Arizona.[10]
It grows in several different habitats, including thesagebrush steppe,blackbrush scrub,piñon–juniper woodlands, and juniper woodlands.[3] The elevation range for the species is quite wide, from 500 to 3,200 meters (1,600 to 10,500 ft).[1]
Like some other members of their genus, the plants are partiallyparasitic, using theirhaustoria to take some, but not all, of the nutrition they require from other plants. Thebig sagebrush and other plants in theaster family are common hosts.[11][12] In a study of the parasitization of big sagebrush by desert paintbrush, they were found to get about 10% of their sugar energy from host plants.[12] In controlled experiments, the desert paintbrush – like orange paintbrush (Castilleja integra) and rough paintbrush (Castilleja scabrida) – was tolerant of being without a host species for short periods.[13]
Desert paintbrushes arehyperaccumulators of the elementselenium.[14]
Pollinators of the plant includebutterflies,hummingbirds, andbees.[8]
As of 2024[update], the conservation status ofCastilleja chromosa has not been evaluated byNatureServe.[15]
