*The following is based on Gann, G.D., K.A. Bradley & S.W. Woodmansee. 2002. Rare Plants of South Florida: Their History, Conservation, and Restoration. The Institute for Regional Conservation: Miami. For updated species accounts, see Citation below. For the original text, follow the link in the Update field. If no Update field is displayed, then cite as the original publication.

Bourreria cassinifolia (A.Rich.) Griseb.

Pineland strongback

South Florida Status: Critically imperiled. Eight occurrences in six conservation areas (Camp Owaissa Bauer; Everglades National Park; Ingram Pineland; Larry and Penny Thompson Park; National Key Deer Refuge; Ned Glenn Nature Preserve) and two non-conservation areas (Old Dixie Pineland; USDA Subtropical Horticulture Research Station).

Taxonomy: Dicotyledon; Boraginaceae.

Habit: Shrub.

Distribution: Native to South Florida and Cuba.

South Florida Distribution: Miami-Dade County and the Monroe County Keys.

South Florida Habitats: Pine rocklands and rockland hammock edges.

Protection Status: Listed as endangered by FDACS and as critically imperiled by FNAI.

Aids to Identification: Scurlock (1987) has color photos; Nelson (1996) has a color photo; Chafin (2000) has illustrations and a color photo.

References: Small, 1933a; Long & Lakela, 1976; Tomlinson, 1980; Scurlock, 1987; Nelson, 1994; Nelson, 1996; Wunderlin, 1998; Chafin, 2000; Coile, 2000.

Synonyms: None.


Historical Context: John Kunkel Small and Joel J. Carter first collected pineland strongback in 1909 in pinelands east of Naranja in Miami-Dade County (2818, NY), in the vicinity of what is now the Homestead Air Reserve Base. Many collections and observations have been made in Miami-Dade County since then, from as far south as Long Pine Key in Everglades National Park (Craighead s.n., USF) to as far north as the USDA Subtropical Horticulture Research Station, where it has been observed by Bradley.

This species is currently extant on seven sites in Miami-Dade County, four of which are conservation areas. Frank C. Craighead first collected it on Long Pine Key in Everglades National Park in 1959 (s.n., Everglades National Park herbarium), and it was observed there as recently as 2000 by the authors and others. Fewer than 100 plants are thought to be present there. It was discovered in the Richmond Pine Rocklands at Larry and Penny Thompson Park in 1978 by George N. Avery (Avery’s Notes, 3 September 1978), and was observed there as recently as 2000 by Bradley and Woodmansee. Fewer than 100 plants are present. This station needs to be vouchered. Avery found it at Camp Owaissa Bauer in 1983 (Avery’s Notes, 9 March 1983), and it was observed there as recently as 2001 by Roger L. Hammer (personal communication, 5 March 2001). One plant is known to be present, and it needs to be vouchered. Bradley vouchered it at the Ned Glenn Nature Preserve in 1995 (104, FTG). Fewer than 10 plants are present there. In 2000, Bradley found one plant at Ingram Pineland, but this station needs to be vouchered.

Of the private sites in Miami-Dade County, the Old Dixie Pineland is the most important as it contains the largest population of pineland strongback in South Florida. This station was first observed by Hammer in 1989 (personal communication, 5 March 2001). Bradley vouchered this station in 1995 (186, FTG). Bradley and others have observed several hundred plants there as recently as 2000. This site should be acquired, but it is in the path of a major transportation corridor, and probably will be destroyed. Another important site is the USDA Subtropical Horticulture Research Station where George N. Avery recorded it in 1974 (Avery’s Notes, 19 May 1974). Bradley observed it there as recently as 1996. Fewer than 10 plants were present. This site is severely threatened by development, and needs to be vouchered. Pineland strongback also was reported for Navy Wells #2 (anonymous, no date.a), a private pine rockland being considered for acquisition by Miami-Dade County, but this report needs to be verified.

Avery discovered pineland strongback outside of Miami-Dade County on Big Pine Key in Monroe County in 1962 (Avery’s Notes, 15 September 1962). The station was reported to be located between the Blue Hole and Koehn’s subdivision. Frank C. Craighead vouchered this population later that year (s.n., Everglades National Park herbarium). Subsequent collections, presumably from the same location on Big Pine, were made by Daniel B. Ward and others in 1964 (4289, FSU), and by W.L. Stern and others in 1970 (2892, FTG). Avery made a number of observations on Big Pine between 1962 and 1976 (Avery’s Notes, 1962-1976), from the station noted above and from a station he referred to as “Cassinifolia Hammock,” an unknown location. T. Ann Williams observed the Koehn’s subdivision population in March 2001 within the National Key Deer Refuge (personal communication, 9 March 2001). Three plants were seen.

Major Threats: Habitat destruction at the Old Dixie Pineland and the USDA Subtropical Horticulture Research Station; fire suppression; exotic pest plant invasions.

Comments: Bradley has observed pineland strongback at a pineland across the street from the Gifford Arboretum at the University of Miami in Coral Gables. This species has been cultivated at the Arboretum, and it is likely that the population across the street from the Arboretum is naturalized from the Gifford Arboretum plants. Pineland strongback is also cultivated in other locations in Miami-Dade County.

Recommendations: • Voucher plants at Camp Owaissa Bauer, Ingram Pineland, Larry and Penny Thompson Park, and USDA Subtropical Horticulture Research Station. • Survey Navy Wells #2. • Map and monitor known stations on a regular basis. • Acquire Old Dixie Pineland. Develop conservation agreement with the USDA Subtropical Horticulture Research Station, and provide technical assistance. • Consider introducing pineland strongback to other sites within its historical range, including Bill Sadowski Park and Deering Estate at Cutler. • Determine status in Cuba.