*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.

Amaranthus floridanus (S. Wats.) Sauer

Florida amaranth


South Florida Status: Historical. Last collected in 1985 at Fort Myers Beach.

Taxonomy: Dicotyledon; Amaranthaceae.

Habit: Annual terrestrial herb.

Distribution: Endemic to peninsular Florida. Wunderlin (1998) reports it as occasional in peninsular Florida. Wunderlin & Hansen (2001) records it for South Florida, and Alachua, Brevard, Duval, Manatee, Pinellas, and Sarasota counties.

South Florida Distribution: Charlotte, Collier and Lee counties, and the Monroe County Keys.

South Florida Habitats: Beach dunes and open disturbed sites.

Protection Status: Not listed by any agency.

Aids to Identification: This is a difficult genus with more than a dozen native and naturalized species in South Florida. A. floridanus is a dioecious plant, with regularly apparent sepals without strong midveins, bracts 1-2 mm long with the midrib conspicuously excurrent, leaf blade usually linear to 1 cm wide, and the inflorescence unbranched above the leaves (Wunderlin, 1998).

References: Chapman, 1883; Small, 1933a; Sauer, 1955; Long & Lakela, 1976; Wunderlin, 1998.

Synonyms: Acnida floridana S. Watson.



Historical Context: John Loomis Blodgett collected the type specimen of Florida amaranth between 1838 and 1853 on the island of Key West (Sauer, 1955). It has not been observed or collected in the Florida Keys since the Blodgett collection. Blodgett also made a collection in the Charlotte Harbor area, also between 1838 and 1853 (s.n., NY). Alvan W. Chapman made a single collection in Collier County in 1895 at “Caseys Pass” at Cape Romano (s.n., GH).

Samuel M. Tracy made the first collection in Lee County in 1901 on Sanibel Island (7621, NY). George R. Cooley rediscovered it on Sanibel Island in 1954 (s.n., FLAS). It was collected several times on Sanibel Island by William C. Brumbach beginning in 1966 (5617, FLAS). Brumbach also collected it in 1968 (6134, FLAS; 6502, FLAS) and 1974 (8697, FLAS). It is uncertain whether or not it is extant on Sanibel. Florida amaranth also was collected on North Captiva Island in 1978 by Sandy Morrill and Jud Harvey (s.n., USF) and in 1979 by Morrill (s.n., USF), possibly in Cayo Costa State Park, although about half of the island is privately owned. It was reported for Cayo Costa Island by Herwitz (1977), but was not found on Cayo Costa Island when it was surveyed from 1990 to 1992 (Herwitz et al., 1996). It was reported for Cayo Costa State Park (Florida Park Service District 4, 1994a), which could have been based upon plants either on North Captiva Island or Cayo Costa Island. Gann and Florida Park Service biologist R. “Bobby” Hattaway surveyed North Captiva Island and Cayo Costa Island within Cayo Costa State Park in February 2001. Habitat for Florida amaranth is present, but no plants were observed. Florida amaranth was collected at Fort Myers Beach twice, once by I.W. Knoblock 1956 (1439, FLAS), and once by Elliott Brown in 1985 (s.n., USF). This was the last known collection. There is also a 1930 collection in Lee County at “Crescent Beach” by Walter M. Buswell (s.n., NY). The location of this station is unknown.

Comments: Florida amaranth is an annual that flowers spring through fall, so surveys should be conducted during this time period. There is a specimen in the herbarium of the New York Botanical Garden that is labeled as having been collected in Colorado. This could represent a short-lived naturalized population, or perhaps a mislabeled specimen.


Recommendations: · Survey the Cape Romano area, Fort Myers Beach, North Captiva Island, and Sanibel Island. · If plants are found, map and monitor known populations. · Review for listing by FDACS and FNAI.