Lignumvitae Key Botanical State Park

Lignumvitae Key is a low island state park off Islamorada, known for its old-growth tropical hardwood hammock and the Matheson family home. You cannot drive to the island: access is by boat or kayak. Arrange water transport before you go. The house and forest trail are tied to ranger-guided visits, so confirm tour availability before building a trip around them. Bring the water and food you need for the outing.

The two-story, four-bedroom house stands in a roughly three-acre clearing and serves as the park's visitor center. One room is furnished in 1930s style; the others have exhibits on the island's natural and cultural history. The grounds include cannons and a wooden approach path, with public restrooms near the dock and tour area. The open lawn gives a clear view of the house's fossil-coral walls and the cannon.

Miami chemist William J. Matheson bought the island in 1919 as a retreat for family and friends. The house's gutters collected rainwater in a concrete cistern, and a 1929 windmill supplied electricity. A small domed concrete shelter was built for hurricanes; the windmill footings and other traces of the island household remain around the house.

The pale limestone came from the island. Look closely and you can find fossilized coral and other marine life from a reef formed about 125,000 years ago. That reef stone connects the house to the Keys landscape under your feet: this is a low island built of ancient coral, not a sandy mainland park.

When the guided nature walk is operating, it leaves the clearing for shaded hardwood forest and reaches a freshwater solution hole about a quarter-mile into the woods. The water is an oasis for birds in the island hammock. Look among the tree trunks for Liguus snails feeding on lichens, and for Florida purplewing butterflies associated with crabwood trees.

More than 10,000 acres of seagrass habitat are protected around the island. Shallow flats can look brown when light reflects off the seagrass below the water. If arriving by boat, follow marked channels: combustion motors are prohibited over park flats shallower than three feet to protect the seagrass.

The island takes its name from the native lignumvitae tree, which once grew abundantly in the hammock. Its exceptionally dense wood was valued for ship rigging because it could lubricate itself as it moved.