*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.

Chamaesyce deltoidea (Engelm. ex Chapm.) Small
subsp. serpyllum (Small) D.G. Burch
Florida Keys wedge sandmat


South Florida Status: Critically imperiled. One occurrence at National Key Deer Refuge, Terrestris Preserve, & adjacent non-conservation areas.

Taxonomy: Dicotyledon; Euphorbiaceae.

Habit: Perennial terrestrial herb.

Distribution: Endemic to South Florida.

South Florida Distribution: Monroe County Keys.

South Florida Habitats: Pine rocklands.

Protection Status: Listed as endangered by FDACS and as critically imperiled by FNAI. Currently under review for listing by USFWS (2001).

Aids to Identification: This can be distinguished from other subspecies of Chamaesyce deltoidea by having irregularly twisted trichomes instead of uncinate trichomes (Wunderlin, 1998).

References: Small, 1933a; Long & Lakela, 1976; Avery & Loope, 1980a; Herndon, 1993; Wunderlin, 1998; Bradley & Gann, 1999b; Coile, 2000.

Synonyms: C. serpyllum Small.



Historical Context: John Kunkel Small first collected Florida Keys sandmat in 1912 on Big Pine Key (3768, NY). It has been collected and observed numerous times since then, but only on Big Pine Key. Florida Keys sandmat is extant at the National Key Deer Refuge, The Nature Conservancy’s Terrestris Preserve (J. O’Brien, personal communication, 1991) and, presumably, on other properties on Big Pine Key. Gann observed plants at the National Key Deer Refuge in 2000. An estimated 1,000-10,000 plants are extant on Big Pine Key (Bradley & Gann, 1999b).

Major Threats: Fire suppression; exotic pest plant invasions; habit destruction; sea-level rise.



Recommendations: • Map and monitor known stations on a regular basis. • Acquire additional habitat and incorporate it into National Key Deer Refuge. • Conduct conservation biology and conservation horticulture studies. • Encourage USFWS to list Chamaesyce deltoidea subsp. serpyllum.

Update: Recent population estimates by Keith A. Bradley indicate that there are more than 10,000 individuals in the Florida Keys, thus changing its status to imperiled in South Florida.

Citation: Gann, G.D. 2006-2012. Species Account Update, Floristic Inventory of South Florida Database Online. The Institute for Regional Conservation. Delray Beach, Florida.