The following Participating Institutions are custodians for this species in the CPC National Collection:
Atlanta Botanical Gardens
Bok Tower Gardens
The conservation of Torreya taxifolia is fully sponsored.
Irina Kadis contributed to this Plant Profile.
Torreya taxifolia is a small, conical tree of the yew family (Taxaceae) and a close relative to Taxus brevifolia from which the cancer drug Taxol is derived. T. taxifolia, or stinking cedar, is an extremely rare conifer that once towered fifty feet above the forested ravines of the Apalachicola drainage system in northern Florida (Godfrey 1968, Foote and Jones 1994). An ancient genus (at least 160 million years old), torreyas were widely distributed across the northern hemisphere during the Jurassic and Pliocene periods.
Named for John Torrey, one of the most distinguished American botanists (1796-1783), this is one of the rarest native trees in the USA: its range is very limited, and within that limited range, it has become nearly extinct. There are no large trees left in their native habitats. What survives are a few scattered young trees (sapling-size) or suckers from root systems and bases of destroyed plants. A fungal disease is the primary cause of this species plight, and remains the largest threat to its survival (USFWS 1986).
Distribution & Occurrence
Understory of the rich hardwood hammock beech-magnolia and mixed hardwood forest (USFWS 1983, 1984, 1985). Canopy trees in these forests are mostly deciduous, but evergreen hardwoods and conifers are also common (USFWS 1986).
Bluffs and woods along the Apalachicola, steep slopes of ravines (mid-slope) with nearly permanent seeps, rises in calcareous bottoms. In Florida, torreya also occurs in lower parts of ravine slopes and adjacent floodplains. T. taxifolia prefers shady habitats with dark, moist sandy loam of limestone origin.
|There are less than 1500 trees in the wild (Schwartz 1993) but continue to decline (Schwartz and Hermann 1993a).|
Conservation, Ecology & Research
Schwartz and Hermann (1993b) conclude that foliar pathogens are the most likely symptom of disease and are associated with a significant decline in photosynthetic capacity brought on by canopy shading. Low light has also been found to be the primary limiting factor to T. taxifolia (Schwartz and Hermann 2000).
Foliar pathogens appear to be sensitive to smoke treatments suggesting that the use fire may play an important role in health maintenance for T. taxifolia (Schwartz and Hermann 1993b).
An examination of endophytic fungal communities found associated with T. taxifolia found that a filamentous fungus, Pestalotiopsis microspora was correlated with diseased and non-diseased trees (Lee et al. 1995).
It is generally believed that T. taxifolia is intolerant to high levels of light, however, Koehn and Doudrick (1999) found that their study plants recovered from periods of high light and temperature indicating that this species may be more tolerant to light than originally thought.
Published research on fire adaptations of Torreya taxifolia (Florida torreya) is lacking. A related species, T. californica (California torreya), sprouts from roots, root crowns, and boles after fire. Torreya taxifolia may respond to fire in a similar manner. Until recently, ground fires were a constant influence on the neighboring long-leaf pine (Pinus palustris) forest community. The smoke from these fires may have operated as a natural fungicide by suppressing a fungus that now infects T. taxifolia. Torreya taxifolia is known from northern Florida and southern Georgia.
The most promising technique for Torreya involved application of cytokinins (4 weekly sprays with 100-200 mg/l BA or 2-i-P) to seedlings before culture. Newly stimulated axillary shoots developed additional shoots and multiple "bud-masses" when cultured on WPM with BA (1 mg/l) and NAA (0.01 mg/l). These were slow to develop but could be subcultured with additional growth of multiple shoots. No rooted plantlets were obtained.
Schwartz, M. W. and S. Herman (1991) present evidence that fire suppression may have contributed to the fungal decline of torreya (Torreya taxifolia). During the 1950s torreya suffered a catastrophic die-back. The torreya die-back was probably caused by needle pathogens induced through environmental stress. Several environmental stresses were concurrent with the decline of the torreya. One of these stresses may have been fire suppression. Torreya grows within ravines, where fires usually do not occur. However, smoke from the frequent natural upland fires settled into ravines. [The authors] present data showing that several needle pathogens isolated from torreya have reduced germination and growth rates on substrates treated with smoke. Succession, as a result of fire suppression, also reduced light incidence within ravines. [The authors] show that torreya growth is correlated with light incidence. [The authors] discuss the fire hypothesis in the context of other hypotheses for the torreya decline. [AA]. Torreya taxifolia is known from Florida and Georgia.,
There are a few large specimens growing undamaged in botanical gardens and nurseries. At several locations in the Southeast, the plantings so far have escaped the fungal disease and produce viable seed.
The plant considered the national champion is in Norlina, NC: it is 45 ft tall to 40 ft wide; a 30-ft-high specimen is in Lee, FL.
T. taxifolia has been often planted on the public grounds in Tallahassee, FL as an ornamental.
Karl Kern, Wyoming Nurseries in Cincinnati, OH supplied the Arnold Arboretum with plants of T. taxifolia. In 1962, Karl Kern said that they had a large specimen in the area that had survived perfectly.
R. Allen, Calloway Gardens, Pine Mountain, GA 31822, collected seeds in Florida in 1981 for the Arnold Arboretum.
Barry Yinger, York Haven, PA (Curator of Asiatic Plants, National Arboretum) in 1983 mailed cuttings from his plant, which, as he stated, had survived -17F in York Co., PA. The plant had originated from Semmes, Alabama.
Rob Nicholson & Ida Hay in 1985 collected cuttings for the Arnold Arboretum north of Chattahoochee and in five places in Torreya State Park, Florida.
Brown, C.L.; Kirkman, L.K. 1993. Trees of Georgia and Adjacent States. Portland, Oregon: Timber Press.
Clewell, A.F. 1985. Guide to Vascular Plants of the Florida Panhandle. Tallahassee, Florida: Florida State University Press. 605p.
Kurz, H.; Godfrey, R.K. 1962. Trees of northern Florida. Gainesville, FL: Univ. Florida Press. 311p.
Little, E.L., Jr. 1978. Atlas of United States trees. Vol. 5: Florida. Miscellaneous Publication No. 1361. Washington, D.C.: U.S. Forest Service. 126p.
USFWS. 1986. Florida torreya (Torreya taxifolia) recovery plan. Atlanta, Georgia: U.S. Fish & Wildlife Service. 42p.