(Vol. 05, 2002-12) Euphorbia (Euphorbiaceae) Section Tithymalus Subsection Lnundatae in the Southeastern United States
Five taxa in Euphorbia section Tithymalus subsection Inundatae are recognized, two representing undescribed taxa here named Euphorbia inundata var. garrettii and Euphorbia rosescens. All are endemic to portions of the outer coastal plain, ranging from southern Georgia to southern Florida and extending west to southern Mississippi, in pyrogenic-evolved pinelands or Florida scrub. Taxonomy of Euphorbia floridana and Euphorbia telephioides is unchanged, with lectotype designation for all Chapman-named species. Euphorbia floridana, an outer East Gulf Coastal Plain endemic, is found on yellowish sands of longleaf pine-turkey oakwiregrass xeric sandhills. Euphorbia telephioides, an Apalachicola Lowlands narrow endemic, is confined to coastal Bay, Franklin, and Gulf counties of the east-central Florida panhandle in xeric, scrubby pinelands. Euphorbia inundata var. garrettii is allopatric with var. inundata, occurring in wet pinelands of southwestern and southcentral Florida. Euphorbia rosescens, a southern Lake Wales Ridge narrow endemic, is known only from Highlands County in peninsular Florida. It is a gap specialist found in Florida scrub types exclusively on xeric, white sand entisols. Morphological, geographical, and ecological factors are shown to distinguish members of the subsection Inundatae, of which all are recognizable by vegetative characters.