Species Brief
Krameria bicolor, white ratany
Written
July, 2026
Contributors
Taryn R. Brahmsteadt - 1st Compiler, Ilana L. Abrahamson - 1st Editor
Brahmsteadt, Taryn R., compiler. 2026. Species Brief: Krameria bicolor, white ratany. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Missoula Fire Sciences Laboratory (Producer). Available: https://research.fs.usda.gov/feis/species-briefs/krabic
Scientific Name
Krameria bicolor
Common Names
white ratany
ratany
Gray's ratany
Gray's krameria
crimson-beak
chacate
cosahui
white rhatany
FEIS Lifeform Type
Shrub
Kingdom
Plantae
Class
Magnoliopsida (Dicot)
Order
Polygalales
Family
Krameriaceae
Genus
Krameria
Nativity
Native
Invasiveness
Noninvasive
This Species Brief is a concise summary of the biological, ecological, and fire‑related characteristics of an individual species derived from a Fire Effects Information System (FEIS) Species Review. Table 1 is derived from a standardized template and highlights these characteristics.
| Attribute | Characteristic | Justification | Source |
|---|---|---|---|
| Biological characteristics | |||
| Life form | Shrub | White ratany is a thorny, intricately branched perennial shrub. | FEIS: Botanical Description [1] |
| Typical lifespan | 101-200 years | The estimated average maximum lifespan is about 184 years, although estimates range from 34 to 404 years. | FEIS: Population Structure [1] |
| Life cycle | Perennial | White ratany is a long-lived perennial shrub. | FEIS: Botanical Description; Plant Growth and Mortality [1] |
| Drought tolerance | High | White ratany is drought-tolerant; however, extended drought may cause shortened lifespan or high mortality rates. | FEIS: Site Characteristics [1] |
| Rooting depth | Shallow* | The root system is a short taproot with radiating shallow lateral roots, though the lower taproot dies and the lateral roots lengthen as the plant ages. | FEIS: Botanical Description [1] |
| Bark thickness at maturity | N/A | This attribute applies to trees. | FEIS: Botanical Description |
| Sheds low branches | N/A | This attribute applies to trees. | FEIS: Botanical Description |
| Reproduction and Regeneration | |||
| Adventitious buds | Root crown* | White ratany can resprout after top-kill or damage from disturbances such as fire. One source states that it may reproduce vegetatively but does not provide details. | FEIS: Postfire Regeneration Strategy; Vegetative Reproduction and Regeneration [1] |
| Time to reproductive maturity | Insufficient information | The source does not provide explicit information about time to reproductive maturity. | FEIS: Entire [1] |
| Soil seed bank longevity | Insufficient information | The source reports that no information is available on this topic. | FEIS: Seed Banking [1] |
| Serotinous cones | N/A | This attribute applies to conifers. White ratany is a shrub that produces spherical, barb-covered fruits. | FEIS: Botanical Description [1] |
| Seed dispersal mechanism | Animal; Gravity | The fruit's spines likely aid dispersal by animals. Gravity is implied because old fruits are often found beneath the plant's canopy. | FEIS: Seed Dispersal [1] |
| Seed dispersal distance | Short (mostly under parent plant); Medium* | Old fruits are often found beneath the plant, but farther dispersal is possible via animals carrying the spiny fruits. | FEIS: Seed Dispersal [1] |
| Optimal conditions for seedling establishment | Nurse plant/object* | White ratany is a root hemiparasite on a variety of shrubs. Although seedlings can establish independently, it may require a host plant to persist. It requires a hemiparasitic attachment to a host rather than typical nurse-plant facilitation. | FEIS: Botanical Description; Seedling Establishment [1] |
| Successional Status | |||
| Shade tolerance | Insufficient information | The source does not provide explicit information about shade tolerance for growth, although white ratany typically grows in open (i.e., sunny) communities. | FEIS: Plant Communities; Entire[1] |
| Successional status | Early*; Late | White ratany is often associated with late-successional communities and described as forming fertile islands, but its resprouting may allow it to persist in early-successional communities after disturbances such as flood or fire. | FEIS: Successional Status; Other Management Considerations [1] |
| Fire | |||
| Primary fire response(s) or adaptation(s) | Recover/Resprout*; Fire Sensitive | White ratany is killed or top-killed by fire but may resprout afterward; it is often a poor resprouter, though moderate to strong resprouting occurs under some conditions. | FEIS: Immediate Fire Effects; Fire Adaptations; Plant Response to Fire [1] |
| Germination is fire stimulated | Insufficient information | No information was available on heating or burning effects on the seeds, and no postfire seedling establishment was described. | FEIS: Immediate Fire Effects [1] |
| Flowering/fruiting is fire stimulated | Rarely/No* | In one study, flower and fruit densities were lower in burned than unburned areas. The source does not address fire-stimulated flowering directly and data are limited, so the call is inferred. | FEIS: Plant Response to Fire [1] |
| Season when it is most sensitive to fire | Insufficient information | White ratany is sensitive to fire. Information regarding degree of sensitivity in different seasons was not addressed in the source, but white ratany appears to be better able to resprout after fire in more mesic microhabitats or during times with relatively high postfire soil moisture content. Thus, it may be more sensitive to fire under dry conditions, which often occurs in late spring and early summer. | FEIS: Plant Response to Fire; Site Characteristics; Seasonal Development |
| Plant flammability | High | Aboveground parts are often consumed by fire because of a receptive fuel structure — low, compact crowns close to surface fuels with finely divided branching. When it burns, it is often partially to completely incinerated. | FEIS: Fuel Characteristics; Immediate Fire Effects [1] |
| Early colonizer/recolonizer of burned or disturbed sites | Rarely/No | White ratany is typically a larger component of undisturbed than disturbed vegetation, and postfire seedling establishment is apparently uncommon. | FEIS: Successional Status; Fire Management Considerations; Postfire Regeneration Strategy [1] |
| Effect of fire exclusion on population | N/A* | Fire intervals are are estimated to exceed several centuries in most communities where white ratany occurs, and fire exclusion has not occurred on a time scale that is relevant to these communities. However, fire frequencies are increasing in many of these communities, and given that white ratany abundance often decreases after fire, fire exclusion in contemporary communities may help to maintain fire return intervals closer to those seen historically and help to maintain white ratany populations. | FEIS: Fire Management Considerations [1] |
| Is this species typically managed with prescribed fire? | Rarely/No | Fire is considered harmful in desert scrub communities where white ratany occurs, and fire prevention is the primary management strategy. | FEIS: Fire Management Considerations; Plant Response to Fire [1] |
| Predominant historical fire frequencies of ecosystem where it most commonly occurs | Infrequent* | Fires were probably rare to infrequent in most communities where white ratany is common, with modeled intervals exceeding several centuries. However, it also grows in perennial-graminoid communities where fire may have been more frequent. | FEIS: Fire Regimes [1] |
| Predominant historical fire severity where it most commonly occurs | Replacement* | Fires were likely replacement severity where white ratany is most common (e.g., Mojave Mid-elevation Mixed Desert Scrub, Creosotebush-White Bursage Desert Scrub). | FEIS: Fire Regimes [1]; LANDFIRE Biophysical Settings (below) |
| Predominant historical fire regime group where it most commonly occurs | 5 | Modeled historical fire intervals exceed several centuries in most communities where white ratany is most common, with predominantly replacement-severity fire — consistent with fire regime group 5. | FEIS: Fire Regimes [1]; LANDFIRE Biophysical Settings (below) |
| Alters historical fuel characteristics of ecosystems where it occurs | Rarely/No* | White ratany is native and does not alter fuels directly, but it may indirectly support higher densities of flammable invasive annual grasses such as bromes beneath its canopy. | FEIS: Fuel Characteristics; Value for Restoration of Disturbed Sites [1] |
| Biophysical Setting | Mean Fire Interval (years) | Fire Severity Percent (%) | ||||||
|---|---|---|---|---|---|---|---|---|
| Code | Fire Regime Group | Low | Mixed | Replacement | All | Low | Mixed | Replacement |
| Series 10820 - Mojave Mid-Elevation Mixed Desert Scrub | ||||||||
| 10820_12_15_16_17_23_24 | V-B | 815 | 815 | 0 | 0 | 100 | ||
| 10820_14 | V-A | 406 | 406 | 0 | 0 | 100 | ||
| 10820_4_13 | V-A | 399 | 399 | 0 | 0 | 100 | ||
| Series 11552 - North American Warm Desert Riparian Systems - Stringers | ||||||||
| 11552_13_14_15 | V-B | 735 | 735 | 0 | 0 | 100 | ||
| Series 10870 - Sonora-Mojave Creosotebush-White Bursage Desert Scrub | ||||||||
| 10870_4_6_12_13_14_15_17_24_25 | V-A | 329 | 329 | 0 | 0 | 100 | ||
| Series 10740 - Chihuahuan Creosotebush Desert Scrub | ||||||||
| 10740_25_26 | ||||||||
| Series 11350 - Inter-Mountain Basins Semi-Desert Grassland | ||||||||
| 11350_13_14 | IV-B | 119 | 119 | 0 | 0 | 100 | ||
| Series 11090 - Sonoran Paloverde-Mixed Cacti Desert Scrub | ||||||||
| 11090_14 | V-B | 1056 | 1056 | 0 | 0 | 100 | ||
| 11090_15_25 | V-B | 1049 | 1049 | 0 | 0 | 100 | ||
| 11090_4_13 | V-B | 1284 | 1284 | 0 | 0 | 100 | ||
| Series 10910 - Sonoran Mid-Elevation Desert Scrub | ||||||||
| 10910_13_14 | IV-B | 104 | 104 | 0 | 0 | 100 | ||
| Summary | ||||||||
| Minimum | 104 | 104 | 0 | 0 | 100 | |||
| Maximum | 1284 | 1284 | 0 | 0 | 100 | |||
| Mean | 630 | 630 | 0 | 0 | 100 | |||
| Median | 571 | 571 | 0 | 0 | 100 | |||
| Percentage of fires in 3 fire severity classes, derived from LANDFIRE succession modeling. Replacement-severity fires cause >75% kill or top-kill of the upper canopy layer; mixed-severity fires cause 26%-75%; low-severity fires cause <26%. | ||||||||
| LANDFIRE. 2020. Biophysical settings models and descriptions, [Online]. Washington, DC: U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior; U.S. Geological Survey; Arlington, VA: The Nature Conservancy, (Producers). Available: https://www.landfirereview.org/search.php [96496] | ||||||||
- Brahmsteadt, Taryn R. 2026. Krameria bicolor, white ratany. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Missoula Fire Sciences Laboratory (Producer). Available: https://research.fs.usda.gov/feis/species-reviews/krabic
Last updated August 24, 2026