Lathyrus bijugatus, drypark pea
Abrahamson, Ilana L., compiler. 2026. Species Brief: Lathyrus bijugatus, drypark pea. 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/latbij
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.
| Attribute | Characteristic | Justification | Source |
|---|---|---|---|
| Biological characteristics | |||
| Life form | Forb | Drypark pea is a perennial, leguminous forb. Its stems may vine, but vining is less pronounced than in legumes with more developed tendrils, so it is treated as a forb. | FEIS: Botanical Description [1] |
| Typical lifespan | Insufficient information | The source does not provide explicit information about the typical lifespan of drypark pea. | FEIS [1] |
| Life cycle | Perennial | Drypark pea is a perennial, leguminous forb. It desiccates in fall and sprouts again in spring. | FEIS: Botanical Description; Seasonal Development [1] |
| Drought tolerance | High* | Drypark pea prefers dry soils and open sites. Soil moisture on sites where it occurs is reported as dry, but drought tolerance is not explicitly stated. | FEIS: Site Characteristics [1] |
| Rooting depth | Medium*; Deep* | Rooting depth of drypark pea is not stated directly, but inferred from the root type. Lathyrus species have caudices, taproots, fibrous horizontal roots, and slender rhizomes growing from the taproot. | FEIS: Botanical Description; Fire Adaptations and Plant Response to Fire [1] |
| Bark thickness at maturity | N/A | This attribute applies to trees. | FEIS: Botanical Description [1] |
| Sheds low branches | N/A | This attribute applies to trees. | FEIS: Botanical Description [1] |
| Reproduction and Regeneration | |||
| Adventitious buds | Rhizomes; Caudex | Drypark pea can sprout from its rhizomes and/or caudex, but it is not clear whether or to what degree it sprouts from either after top-kill. | FEIS: Vegetative Regeneration; Botanical Description [1] |
| Time to reproductive maturity | Insufficient information | The source does not provide explicit information about the time to reproductive maturity. | FEIS [1] |
| Soil seed bank longevity | Insufficient information | Lathyrus species have a soil-stored seed bank, but the long-term viability of drypark pea seed is not documented. | FEIS: Seed Banking [1] |
| Month(s) when seeds typically ripen | July*; August*; September* | Rangewide information about drypark pea's fruiting season is not available. MoreHowever, in the eastern Oregon Cascades, plants fruit in early to mid-August, and pods are well matured by fall. In most areas, flowering dates range from May to July, so it is likely that fruiting dates range from July to September. | FEIS: Seasonal Development [1] |
| Serotinous cones | N/A | This attribute applies to conifers. Drypark pea produces a two-valved pod that bears 6 to 12 seeds. | FEIS: Botanical Description [1] |
| Seed dispersal mechanism | Insufficient information | Information on drypark pea seed dispersal was lacking in the literature. | FEIS: Regeneration Processes [1] |
| Seed dispersal distance | Insufficient information | Information on drypark pea seed dispersal distance was lacking in the literature. | FEIS: Regeneration Processes [1] |
| Optimal conditions for seedling establishment | Insufficient information | Information on drypark pea seedling establishment was lacking in the literature. | FEIS: Regeneration Processes [1] |
| Successional Status | |||
| Shade tolerance | Shade intolerant* | As its name implies, drypark pea prefers open sites with dry soil. It is rare in late-successional conifer forests, but its shade tolerance is not stated directly. | FEIS: Site Characteristics; Successional Status [1] |
| Successional status | Early* | Drypark pea occurs on open sites, including clearings, and is rare in late-successional conifer forests, but its successional status is not stated directly. | FEIS: Successional Status [1] |
| Fire | |||
| Primary fire response(s) or adaptation(s) | Recover/Resprout* | Fire probably top-kills drypark pea, and it likely sprouts from its rhizomes and/or caudex after top-kill. MoreHowever, these responses are undocumented. One study suggests that fires of low or high intensities may not substantially affect its abundance in the short term. | FEIS: Immediate Fire Effects; Fire Adaptations and Plant Response to Fire [1] |
| Germination is fire stimulated | Insufficient information | Little is known of drypark pea's germination requirements, and no fire cue for germination is described. | FEIS: Germination [1] |
| Flowering/fruiting is fire stimulated | Insufficient information | The source does not provide explicit information about fire-stimulated flowering or fruiting in drypark pea. | FEIS [1] |
| Season when it is most sensitive to fire | Insufficient information | Information was not available about seasonal differences in drypark pea's fire sensitivity. MoreIn the only available fire study on the species, drypark pea cover and frequency 1-3 years after fall prescribed fires were similar to those on unburned plots. | FEIS: Fire Adaptations and Plant Response to Fire [1] |
| Plant flammability | Insufficient information | The source does not provide explicit information about the flammability of drypark pea. MoreBecause it is rare even in the plant communities where it occurs, it does not substantially contribute to fine fuels. | FEIS: Fuels [1] |
| Early colonizer/recolonizer of burned or disturbed sites | Insufficient information | The single fire study found cover and frequency similar on unburned plots and plots burned under low or high intensity, but no evidence describes colonization of newly burned or disturbed sites. | FEIS: Fire Adaptations and Plant Response to Fire [1] |
| Effect of fire exclusion on population | Possible decrease | Because drypark pea occurs in open plant communities, fire exclusion could increase canopy cover, which could decrease its abundance, especially in conifer woodlands and forests. | FEIS: Fire Management Considerations [1] |
| Is this species typically managed with prescribed fire? | Rarely/No* | Only one study documented drypark pea after fire, where it was incidental to prescribed burns applied to logged ponderosa pine. MoreIt is unlikely that drypark pea is managed with fire, and the source does not describe it. | FEIS: Fire Adaptations and Plant Response to Fire [1] |
| Predominant historical fire frequency where it most commonly occurs | Frequent; Mid-frequency | Drypark pea grows in open conifer forests, Palouse prairies, mountain grasslands, and on the edges of big sagebrush communities. MoreOpen ponderosa pine, Douglas-fir, and western larch forests historically experienced mostly frequent, low-severity fires. Historical fire intervals in Wyoming big sagebrush communities were likely over 66 years. | FEIS: Fire Regimes; Plant Communities [1] |
| Predominant historical fire severity where it most commonly occurs | Low; Mixed*; Replacement* | Open conifer forests historically experienced mostly frequent, low-severity fires. MoreWestern larch and subalpine fir stand types experienced some mixed-severity and some stand-replacing fire, and big sagebrush communities historically had stand-replacement and patchy, mosaic fires. | FEIS: Fire Regimes [1] |
| Predominant historical fire regime group where it most commonly occurs | 1; 4* | The source does not assign fire regime groups directly, but open ponderosa pine, Douglas-fir, and western larch forests had mostly frequent, low- to mixed-severity fires (group 1), and big sagebrush communities historically had mid-frequency, stand replacing fire (group 4). | FEIS: Fire Regimes [1] |
| Alters historical fuel characteristics of ecosystems where it occurs | Rarely/No | Because drypark pea is rare even in the plant communities where it occurs, it does not substantially contribute to fine fuels. | FEIS: Fuels [1] |
1. Fryer, Janet L. 2021. Lathyrus bijugatus, drypark pea. 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/latbij