Linum carteri Small var carteri
Species Name: Linum carteri Small var carteri (1905)
Common Name(s): Carter’s Flax
Synonym(s): Cathartolinum carteri (Small) Small (1907); Linum rigidum Pursh var. carteri (Small) C.M. Rogers (1963)
Family: Linaceae
Species/taxon description: (adapted from Chafin, 2000) Herb 10-60 cm (4-24 inches) tall, branched throughout (Mosquin and Hayley, 1967). Alternate leaves 1-3 cm (0.4-1.2 in) long, very narrow, red gland at attachment point to stem. Flowers (5 petals, 5 sepals) are yellow (sometimes ranging from white to dark yellow) with a 1.5 cm (0.5 inches) corolla. Corolla is shed less than 6 hours after opening. Fruit, a capsule, opens into 5 star-shaped segments. Sepals not persistent in fruit. 2n= 60 (Robertson, 1971).
Legal Status: Florida endangered. Federal candidate.
Biogeographic value: Native. Endemic. Rare. Only three populations occur on conservation lands.
Prepared by: Meghan Fellows, Jennifer Possley, Cynthia Lane and Joyce Maschinski, Conservation of South Florida Endangered and Threatened Flora (ETFLORA) Project, Research Department, Fairchild Tropical Garden
Last Updated: Maschinski, September 2004
M. Fellows
Background and Current Status
Range-wide distribution – past and present
Florida {CONFIDENTIAL}
Population and reproductive biology/life history
Annual/Perennial: Annual (Chafin, 2000; Rogers, 1963) – short-lived perennial (Maschinski, pers. obs.)
Habit: Herb
Short/Long-Lived: Short; Locally abundant for short periods of the year (Tatje, 1980)
Pollinators: unknown. May be self-pollinated (Mosquin and Hayley, 1967).
Flowering Period: Spring (Wunderlin, 1998; Long and Lakela, 1971); Feb -August (Maschinski et al., 2002; Chafin, 2000); Requires disturbance to bloom (Tatje, 1980); Does not necessarily need disturbance to bloom (Maschinski et al., 2002).
Fruiting: (Feb-) May – (-May) August (Maschinski et al., 2002; Chafin, 2000); Plants collected in August had few seeds (with 0% germination at 4 weeks post collection) each flowering head had 6 or fewer seeds (although, morphologically, the maximum number could be 10) (Maschinski et al., 2002).
Annual variability in Flowering: unknown.
Growth Period: unknown
Dispersal: wind?
Seed Maturation Period: unknown
Seed Production: 0-10/Fruiting Structure (Maschinski et al., 2002)
Seed Viability: unknown
Regularity of Establishment: Seeds of Linum arenicola tend to germinate and establish more successfully in cultivation than seeds of Linum carteri var. carteri (Carrera, pers. comm.).
Germination Requirements: unknown
Establishment Requirements: unknown
Population Size: 2003 estimate: 10,300
Intrannual Variation: It appeared as if there are more aboveground plants in June than in August at 3 sites; at other sites there was no obvious decrease – monitoring should coincide with this natural variation (Maschinski et al., 2002).
Annual Variation: unknown
Number and Distribution of Populations: {CONFIDENTIAL}
Habitat description and ecology
Type: PINE ROCKLAND. Disturbed edges (i.e. road cuts) of Pine Rocklands
Physical Features:
Soil: calcareous (Rogers, 1963) and in tiny, less than 10 cm (4 in) diameter, and 5 cm (2 in) deep soil pockets in limestone rock surface (Maschinski et al., 2002).
Elevation: unknown
Aspect: unknown
Slope: 0-10% (Maschinski et al. 2002)
Moisture: Probably low, sites are disturbed and open (Maschinski et al. 2002)
Light: high (Maschinski et al. 2002)
Biotic Features:
Community: Associated native Species: Pinus elliottii var. densa, Serenoa repens, Myrica cerifera, Metopium toxiferum, Sideroxylon salicifolium, Schizachyrium sanguineum, Schizachyrium gracile, Aster adnatus, Acalypha chamaedrifolia (Bradley and Gann 1999). Associated exotic or weedy species: Bidens alba var. radiata, Eremochloa ophiuroides, Desmodium ssp., Stenotaphrum secundatum (Bradley and Gann 1999). Also observed Sabal palmetto; Jacquemontia curtissii; Crossopetalum ilicifolium; Agalinis sp., Polypremum procumbens. (Maschinski et al. 2002)
Interactions:
Competition: unknown
Mutualism: unknown
Parasatism: Love vine noted on a few individuals (16 Aug 2001, Maschinski et al. 2002)
Host:
Other:
Animal use: unknown
Natural Disturbance:
Fire: Could be beneficial as it creates openings in the habitat. The potential for adults to survive from rootstock is unknown.
Hurricane: unknown
Slope Movement: unknown
Small Scale (i.e. Animal Digging): unknown
Temperature: unknown
Protection and management
Summary: The following needs have been identified: Acquisition of privately owned lands, management of plants at protected and federal sites, control exotics (Chafin, 2000), fire, prevention of mountain biking, reintroduction into intact pinelands w/fire near the sites it currently occurs (Chafin, 2000; Bradley and Gann, 1999). Populations that are on protected lands are on road edges, suggesting that the very open habitat created by large scale disturbance is beneficial to the species – at this time, it is not recommended that this disturbance cease except in cases where the entire colony is smothered (plant waste, land slide).
Availablity of source for outplanting: none. Plants flowered within 90 days when planted in a greenhouse in mid-November, 65F night/85F day, 16H light: 8H dark (Mosquin and Hayley, 1967)
Availabiliy of habitat for outplanting: Fairchild Tropical Garden new pine rockland exhibit; possible NAM and EEL sites
Threats/limiting factors
Natural:
Herbivory: unknown
Disease: unknown
Predators: unknown
Succession: from pine rockland
Weed invasion: Weeds forming dense mats (e.g. Cassytha filiformis) may prevent establishment/reduce fitness.
Fire: unknown
Genetic: lack of dispersal between populations?
Anthropogenic
On site: Urbanization, fire supression (Tatje 1980); recreational use (mountain biking), development, exotic species, modification of fire regime, mechanical disturbance, herbicide use (Bradley and Gann 1999); mowing, invasive species (native and exotic) (Maschinski et al. 2002). Disturbance from mowing retarded the maturation of plants in the population, decreased plant height and branching, but increased plant densities. Preliminary evidence suggests that it does not affect overall fruit production (Maschinski and Bradley 2004).
Off site: The 5 populations with the most plants are not on conservation lands
(Bradley and Gann, 1999); Only 3 of the 9 occurrences are on conservation lands (Bradley and Gann, 1999). One population was destroyed in 2003 and a second is slated for development (Maschinski, 2003).
Collaborators: United States Department of Agriculture
Conservation measures and actions required
Research history: Few people have conducted research on this species, with the notable exception of Mosquin and Hayley (1967). Mosquin and Hayley (1967) conducted crosses between Linum rigidum var. carteri (a synonym for Linum carteri var. carteri) and several of its hypothesized close relatives. As a result of their work, they hypothesize that this species is over a million years old, migrating to Florida from Texas (Mosquin and Hayley, 1967). Previous work has been primarily in the form of herbarium specimens, plant surveys and plant descriptions (e.g. Robertson, 1971).
Significance/Potential for anthropogenic use: Linum carteri var. carteri is a member of the Linum rigidum complex, and therefore may contain the -carotenoids leutin and 5,6-monoepoxide (Robertson, 1971) both of which are hypothesized to reduce the risk of certain cancers.
Recovery objectives and criteria: There are no federal objectives or criteria for this species.
Management options:
Introduction onto Conservation Lands
Although this would serve the long-term purposes of protecting a large portion of the total number of populations, at this time, little is known about the propagation or habitat requirements for this species. Once horticulture methods have been developed, there exist multiple protected sites within the home range of the species that could be suitable for an introduction event.
Increase Population Sizes/ Improve current Habitat
Improving population size and habitat serves to further protect the populations that occur there from stochastic, random events. Unfortunately, many locations where Linum carteri var. carteri occurs are not protected. Nor are the habitat requirements sufficiently proven to recommend any specific management plan.
Protect privately held lands, move to acquisition lists
Protecting populations not currently on conservation lands can address the first threat this species faces – development. However, management methods must be worked out so that the protected area does not develop into a less-disturbed habitat type thereby excluding this disturbance-phyllic species.
Next Steps:
Fairchild began demographic studies of the species in 2002 and expanded these in 2003 to determine the impact of mowing on population growth. Propagation Research is also needed.
References
Bradley K., G. Gann. 1999. Status Summaries of 12 Rockland Plant Taxa in Southern Florida. Report submitted to USFWS, Vero Beach, Florida. IRC (Institute for Regional Conservation). 82 pages.
Chafin, L. 2000. Carter’s Flax. In Florida Natural Areas Inventory.
Coile N.C. 2000. Notes on Florida’s Endangered and Threatened Plants Florida Dept. of Agriculture and Consumer Services; Report nr Botany Section Contribution No. 38.
Godfrey, R. K. & J. W. Wooten. 1981. Aquatic and Wetland Plants of Southeastern United States Dicotyledons. 933 pp.
Long, R.W. and O. Lakela. 1971. A Flora of Tropical Florida. University of Miami Press. Coral Gables, FL.
Maschinski, J and K. Bradley. 2004. Demography of Linum carteri var. carteri growing in disturbed and undisturbed sites. In Maschinski, J., K. S. Wendelberger, S. J. Wright, H. Thornton, A. Frances, J. Possley and J. Fisher. Conservation of South Florida Endangered and Threatened Flora: 2004 Program at Fairchild Tropical Garden. Final Report Contract #007997. Florida Department of Agriculture and Consumer Services, Division of Plant Industry, Gainesville, FL.
Maschinski, J., M.Q.N. Fellows, J. Possley. 2002. Conservation of South Florida Endangered and Threatened Flora. Final Report to the Endangered Plant Advisory Council, Florida Department of Agriculture and Consumer Services, FDACS Contract # 006466.
Mosquin, T. and D.E. Hayley. 1967. Evolutionary relationships of the southern Florida populations of Linum rigidum (Linaceae). Canadian Journal of Botany 45:1277-1283.
Robertson, K. R. 1971. The Linaceae in the southeastern United States. Journal of the Arnold Arboretum. 52:649-665.
Rogers, C. M. 1963. Linum rigidum. Brittonia. 15:99-101.
Rogers, C. M. 1968. A reassessment of Linum rigidum and Linum carteri (Linaceae) in Florida. Sida 3(4):209-210.
Tatje, B. E. 1980. Linum carteri Small var carteri. In D. F. Austin. Endangered and threatened plant species survey in Southern Florida.
Wunderlin, R. P. 1998. Guide to the Vascular Plants of Florida. University Press of Florida. 806 pgs
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