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Fritillaria pluriflora

Torr. ex Benth.

Adobe Lily

G2Imperiled (G2G3) Found in 4 roadless areas NatureServe Explorer →
G2ImperiledGlobal Rank
High - mediumThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.154350
Element CodePMLIL0V0F0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single state or province
KingdomPlantae
PhylumAnthophyta
ClassMonocotyledoneae
OrderLiliales
FamilyLiliaceae
GenusFritillaria
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Conservation Status
Rank MethodLegacy Rank calculation - Excel v3.1x
Review Date2015-09-01
Change Date2015-09-01
Edition Date2015-09-01
Edition AuthorsMichael Schindel (Mar/1997); K. Maybury (Jun/1997); Griggs, Mary Ann (Jun/1997), rev. K. Gravuer (2009), rev. R. Bittman (2015)
Threat ImpactHigh - medium
Range Extent5000-20,000 square km (about 2000-8000 square miles)
Number of Occurrences21 - 80
Rank Reasons
Endemic to northern California, where scattered in the interior foothills of the North Coast Ranges and the northcentral Sierra Nevada, extending on both sides into the edges of the intervening Sacramento Valley. There are 107 mapped occurrences, 34 of which have been seen within the last 20 years. Two occurrences have relatively large numbers of plants ("several million" and "tens of thousands"), but most other occurrences have only a few hundred plants and probably comprise less that 30,000 individuals in total. Approximately half of occurrences are on private land and many others are on BLM land. Threats include inundation of habitat for reservoirs, residential/recreational development, road construction and maintenance, incompatible grazing regimes, off-road vehicles, exotic plants, mining, and horticultural collection.
Range Extent Comments
Endemic to the interior foothills of the North Coast Ranges and the north-central Sierra Nevada, as well as the edges of the intervening Sacramento Valley, California; in Napa, Yolo, Colusa, Lake, Glenn, Butte, and Tehama counties. The species does not occur throughout the occupied counties, however; most known occurrences are found in a narrow north-south band that intersects many county lines. Significant clusters of occurrences are found in and around Bear Valley (Colusa and adjacent Lake counties) and around Stonyford and nearby East Park Reservoir (straddling the Lake-Colusa county line). The Jepson Manual (Hickman 1993) and Fiedler (1996) include southern Oregon in the range, but these reports appear to be in error.
Occurrences Comments
107 mapped occurrences, 34 of which have been seen within the last 20 years; the rest need rechecking (CNDDB 2015).
Threat Impact Comments
Threatened by grazing, roads, development, and ORV's (CNDDB 2015). More specifically, threats to the Adobe lily include:

Loss of habitat: (1) Inundation of habitat for reservoirs; (2) type conversion (e.g., grassland to row crops. Adobe lily does not survive tilling); (3) residential/recreational development; (4) roads and road edge maintenance (e.g., herbicide use); (5) deposition of mine tailings on habitat.

Degradation of habitat: (1) Competition or shading by exotics; (2) over-grazing for a multi-year period; (3) off-road vehicles; (4) horticultural collecting.

Any kind of grazing is often cited as a threat to this plant, but this assertion is not supported by field observations. The largest occurrence of adobe lily (several million plants in Bear Valley) has co-existed with grazing for a century. From experience at The Nature Conservancy's Vina Plains Preserve, adobe lily does not grow through the dead plant material that accumulates in ungrazed and unburned grassland. Once thatch was removed (in this case by burning) adobe lilies grew and bloomed in high numbers (1997, Wurlitzer addition, Vina Plains Preserve).

Most documented occurrences are near roads.
Ecology & Habitat

Diagnostic Characteristics

Fritillaria pluriflora is easily distinguished from other fritillaries by the uniformly pinkish-lavender color of the petals. This must be seen in the very early spring (February to mid-March) before most wildflowers begin blooming.

Habitat

On the west side of the Sacramento Valley in the Coast Range foothills, adobe lily occurs in foothill valley grasslands and on sloping openings in blue oak woodland and chaparral. These occurrences (Napa, Yolo, Colusa, Lake, Glenn and western Tehama counties) are in heavy clays ("adobe" soils), Maxwell series and East Park gravelly clay, and serpentine-derived Heneke series clays (180 - 640 m elevation, with one occurrence at 820 m). On the east side of the Sacramento Valley (Butte and eastern Tehama County occurrences) Adobe lily occurs in heavy clay with no serpentine influence at lower elevation (60 m) in open grassland. These east side occurrences are at the base of the southern Cascade Range foothills on soils derived from basaltic alluvium (Anita clay). There are no occurrences associated with Sierran foothills. Associates include zigadena lilies (Zigadenus fremontii), blue oak (Quercus douglasii), fringed onion (Allium fimbriatum), naked-stemmed buckwheat (Eriogonum nudum), and California dwarf flax (Hesperiolinon californicum).

Ecology

Ecology: Fritillaria pluriflora occurs only where there are deep clay soils with a high water-holding capacity and direct sunlight. Adobe lily blooms very early in the growing season before exotic annual grasses and forbs are tall enough to shade it. The bulbs are eight or more inches beneath the soil surface and thus have protection from fires and to an uncertain extent from the hoof action of grazing livestock.

Reproductive System: Sexual and vegetative. Relative frequency of sexual and vegetative reproduction is unknown.

Pollen vectors: Biotic; little is known about pollinators of adobe lily. Bumble bees and moths have been observed visiting the flowers.

Dispersal vectors: Cattle and deer have been observed eating the seed capsules. The assumption has been that the seeds do not survive the digestive tract of either animal. Pocket gophers collect and store native perennial bulbs in their underground burrows and neglect to eat them all. Liliaceous perennials have been observed growing in small dense clusters from these underground caches. Thus the gophers are dispersal agents. The action of cattle hooves on saturated adobe soils may divide clusters of fritillary bulbs and provide a sort of cultivation or very localized dispersal (an untested hypothesis).

Reproductive Comments: There have been very few studies of Fritillaria pluriflora. One investigator of populations on the east side of the Sacramento Valley ( J. Witzman, 1991) found that recruitment was happening. There were plants of many sizes, from seedlings to big plants. Plants may stay in the one leaf stage for several years and later gain one leaf per year. The largest plants may be 15 to 20 years old. She also found that a significant proportion of the flowers were not fertile. These infertile flowers had a shorter than normal style.

Reproduction

Reproductive system: Sexual and vegetative. The relative frequency of sexual and vegetative reproduction is unknown.

Phenology/Seasonality: Perennial, early Spring-flowering (February - mid-March). Bulbous native perennials can remain dormant in unfavorable years. For adobe lily, a favorable year is one in which there is rainfall in autumn and early winter, sufficiently in advance of the blooming period. Provided there is favorable rainfall, a few warm days in February are enough to trigger blooming in the lowest elevation occurrences at The Vina Plains Preserve (TNC). The foothill populations may not bloom until two or more weeks later than those at Vina Plains. Flowers last for one to two weeks, depending on humidity. Seed capsules may be found into May. From June until February there is very little visible evidence of adobe lily.

Pollen vectors: Biotic; little is known about pollinators of adobe lily. Bumble bees and moths have been observed visiting the flowers.
Terrestrial Habitats
Forest/WoodlandWoodland - MixedShrubland/chaparralGrassland/herbaceous
Other Nations (1)
United StatesN2
ProvinceRankNative
CaliforniaS2Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial development———
1.1 - Housing & urban areas———
2 - Agriculture & aquaculture———
2.1 - Annual & perennial non-timber crops———
2.3 - Livestock farming & ranching———
4 - Transportation & service corridors———
4.1 - Roads & railroads———
6 - Human intrusions & disturbance———
6.1 - Recreational activities———
7 - Natural system modifications———
7.2 - Dams & water management/use———

—

Plant Characteristics
Economic Value (Genus)No
Roadless Areas (4)
California (4)
AreaForestAcres
Deer MountainMendocino National Forest11,716
GrindstoneMendocino National Forest26,031
IshiLassen National Forest21,805
Reister CanyonMendocino National Forest5,897
References (16)
  1. Blackburn, T.C. and K. Anderson. 1993. Before the Wilderness, Environmental Management by Native Californians. Ballena Press, Menlo, CA.
  2. California Department of Conservation, Office of Mine Reclamation in Cooperation with the Division of Mines and Geology, DMG open file report, August 4, 1995 (revised). Publications and Information Office, (916) 445-5716.
  3. California Department of Fish and Game. 1997a. <i>Fritillaria pluriflora</i> element file. California Dept. of Fish and Game, Natural Diversity Data Base.
  4. California Department of Fish and Game. 1997b. Special plants list. California Department of Fish and Game, Natural Heritage Division, Natural Heritage Diversity Database.
  5. California Native Plant Society (CNPS). 2009. Inventory of Rare and Endangered Plants. California Native Plant Society. Sacramento, CA. Online. Available: http://www.cnps.org/inventory (accessed 2009).
  6. California Natural Diversity Database (CNDDB). 2015. RareFind Version 5.1.1. California Department of Fish and Game, Sacramento, CA.
  7. Edwards, S. W. 1994. Bear Valley: wildflowers as John Muir described them. Fremontia 22(4): 12-16.
  8. Fiedler, P.L. 1996. Rare Lilies of California. California Native Plant Society Press, Sacramento, California. 154 pp.
  9. Flora of North America Editorial Committee (FNA). 2002a. Flora of North America north of Mexico. Vol. 26. Magnoliophyta: Liliidae: Liliales and Orchidales. Oxford Univ. Press, New York. xxvi + 723 pp.
  10. Hickman, J. C., ed. 1993. The Jepson manual: Higher plants of California. University of California Press, Berkeley, CA. 1400 pp.
  11. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
  12. Oswald, V.H., and L. Ahart. 1994. Manual of the vascular plants of Butte County, California. California Native Plant Society, Sacramento. 348 pp.
  13. Savory, A. 1988. Holistic Resource Management. Island Press, Washington, D.C.
  14. Schlising, R. A. and S. A. Chamberlain. 2006. Biology of the geophytic lily, <i>Triteleia laxa</i> (Themidaceae), in grasslands of the northern Sacramento Valley. Madroño 53(4): 321-341.
  15. Skinner, M.W., and B.M. Pavlik, eds. 1994. California Native Plant Society's Inventory of rare and endangered vascular plants of California. 5th edition. California Native Plant Society, Sacramento. 338 pp.
  16. Witzman, J. 1991. The biology of <i>Fritillaria pluriflora</i> (Liliaceae): a rare endemic of the California flora. M.S. thesis in Botany, California State University, Chico.