Question: In which county in Florida is the Euphorbia deltoidea indigenous?

Context paragraphs:
Euphorbia deltoidea: Euphorbia deltoidea (syn.  "Chamaesyce deltoidea") is a species of flowering plant endemic to Florida in the United States.  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".  One subspecies, ssp.  "deltoidea", is a federally listed endangered species called deltoid spurge.  It is found only in Miami-Dade County.  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.  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.

Cockroach Bay Aquatic Preserve: Cockroach Bay Aquatic Preserve is a protected area that includes 4,800 acres of partially submerged lands in Hillsborough County near Ruskin, Florida south of Tampa, Florida.  Archaeological evidence from indigenous tribes have been found in the area.  The coastal uplands, freshwater wetlands and estuarine habitats provide sanctuary for young fish including red drum and snook as well as numerous birds, crustaceans and other species.  Aquatic habitats include seagrass and oyster beds.

Miami-Dade County, Florida: Miami-Dade County is a county located in the southeastern part of the U.S. state of Florida.  It is the southeasternmost county on the U.S. mainland.  According to a 2016 census report, the county had a population of 2,712,945, making it the most populous county in Florida and the seventh-most populous county in the United States.  It is also Florida's third-largest county in terms of land area, with 1946 sqmi .  The county seat is Miami.

Supporting paragraphs: Euphorbia deltoidea Miami-Dade County, Florida
Answer: Miami-Dade County