|Cox's mariposa-lily, crinite mariposa lily|
|Godfrey & Callahan|
|Edward Guerrant, Ph.D.|
The following Participating Institutions are custodians for this species in the CPC National Collection:
Rae Selling Berry Seed Bank & Plant Conservation Programs
The conservation of Calochortus coxii is fully sponsored.
Edward Guerrant, Ph.D. contributed to this Plant Profile.
When the crinite mariposa lily is not in bloom, it can be difficult to distinguish from grasses and is easily overlooked. Perhaps for this reason it was not discovered until the spring of 1988. However, this plant is akin to the ugly ducking that matures into a swan, as reproductive plants are graced with attractive, white, cup-shaped flowers each spring.
The Calochortus genus contains a relatively large number of rare, localized, and endemic taxa (Feidler et at. 1998). The crinite mariposa lily is one such taxon. It occurs only within a narrow 30-mile (50-km) long band of serpentine soil that contains large amounts of iron and magnesium (Fredricks 1992). Even within this specific soil type, the crinite mariposa lily is not widely distributed as it primarily occupies the transition zone between coniferous forests and meadows.
Distribution & Occurrence
Restricted to serpentine soils (Knight and Seevers 1992). Primarily found in the transition zone (ecotone) between coniferous forests and grass-shrub meadows, but also found in meadows (Fredricks 1993).
Elevation 1400 to 2500 ft. (420-760 m) (Fredricks 1989).
|There are 11 known sites, of which 8 are on Bureau of Land Management (BLM) land and 3 on private land. Population numbers as of 1992 and 1993 ranged from as little as two individuals to over 5,000, but most populations contained between 100 and 1000 individuals (ONHDB 2000).|
Conservation, Ecology & Research
Physical and chemical properties of serpentine soils that may cause reduced reproductive success include restricted rooting depth, stoniness, low levels of molybdenum, paucity of soil micro-organisms, low levels of available macronutrients, high levels of nickel, chromium, zinc, and magnesium and low calcium to magnesium ratio (Rai et al. 1970 in Fredricks 1992).
Most research shows that in cultivation, serpentine endemics grow robustly on non-serpentine soil. Competition and the presence of pathogenic fungi not found on serpentine are most commonly suggested as the factors limiting plants to serpentine soils (Fredricks 1993). Fielder (1985) hypothesizes that heavy metal tolerance in Calochortus may be an exadaptation, meaning that it evolved early but has been repeatedly lost throughout the lineage.
Growth rates of Calochortus coxii appear slower than those of Calochortus umpquaensis, especially when compared across the same habitat. C. coxii most commonly occupies litter and moss habitats, with the litter microsites the most common and comprising the greatest cover. While bud production is higher in C. coxii than in the forest and meadow habitats of C. umpquaensis, capsule production and recruitment are significantly lower. Grazing and seed predation may contribute to this low fecundity (Fredricks 1993). Grazing of vegetative matter causes a reduction in size and reproduction the following year due to depletion of carbohydrate reserves (Fredricks 1989). The high variability in seed set may also indicate that pollination may be limited. Unlike other species of Calochortus, which are frequently visited by beetles and bees, insect visitors to C. coxii are rarely observed. The sparseness of flowering individuals may also be responsible for low pollination (Fredricks 1993).
Calochortus coxii reproductive output varies considerably across habitat. In general, Calochortus life history is typical of long-lived herbaceous perennials: individual survival makes the largest contribution to growth rate, reproduction and mortality appear episodic, and reproductive success and seedling establishment appear to limit populations to certain habitats (Feidler et al. 1998).
Grazing (Fredricks 1993).
Seed predation (Fredricks 1993).
Demographic comparisons using matrix model analysis of empirical data were made among eight Calochortus species. Results paint a mixed picture of population dynamics. For all species, population stage distribution (proportion of seedlings, juveniles, and reproductive adults) was highly variable between populations, habitats, and years. (Feidler et al. 1998).
Germination trials indicate that germination is stimulated by long periods (12-14 weeks) of cold, moist, dark stratification. This ensures that the seed will only germinate in the spring, when the seedlings chance for survival is greatest (Florance 1994).
In germination studies at The Berry Botanic Garden, 100% germination was obtained after 8 weeks of cold stratification followed by a constant 68F (20C) environment. Between 80-100% of seeds germinated with 8 weeks of cold stratification and an alternating 50F/68F (10/20C) environment (BBG file).
Determine the mechanism facilitating endemism to serpentine soils (Fredricks 1989).
Soil and microsite analysis to identify critical factors to recruitment and success (Fredricks 1989).
Continued monitoring (Fredricks 1992).
Determine optimum propagation procedures and develop reintroduction protocols.
Fiedler, P.L.; Knapp, B.; Fredericks, N. 1998. Rare plant demography: Lessons from the Mariposa Lilies (Calochortus: Liliaceae). In: Fiedler, P.L.; Kareiva, P. M., editors. Conservation Biology: Conservation for the Coming Decade. Chapman & Hall. New