Euphorbia deltoidea (syn. Chamaesyce deltoidea) is a species of flowering plant endemic to Florida in the United States.[1] The taxonomy of the plant is difficult, with some authorities dividing it into four subspecies and some into three; also, it is frequently listed as a member of the old genus Chamaesyce.[1] [2] One subspecies, ssp. deltoidea, is a federally listed endangered species called deltoid spurge.[2] It is found only in Miami-Dade County.[1] Another subspecies, ssp. adhaerens, is often included with it under the name deltoidea instead of separately, making it difficult to keep count of how many endangered plants there are.[2] This is generally dealt with by placing the "endangered species" label on any taxon within the species that is limited to Miami-Dade County, however many names they may have.[1]
The deltoid spurge grows in a heavily populated county which has been overtaken by urban development. About 98% of the plant's natural habitat has been drastically altered or destroyed, causing its rarity.[1] The plant grows in South Florida's pine rocklands, an increasingly rare type of forest habitat that is stabilized by periodic wildfire.[3] The plant grows in open, sunny areas and depends on fires to clear away brush and litter that threaten to shade it out.[1] Fire suppression in Miami-Dade prevents this natural fire regime.[1] Other threats to the species include invasive plant species such as Burma reed (Neyraudia reynaudiana).[1]