Fla. Stat. § 6.03

If the officer or other agent employed by the United States to make such purchase and the owner of the land contemplated to be purchased, as aforesaid, cannot agree for the sale and purchase thereof, the same may be acquired by the United States by condemnation in the same manner as is hereinafter provided for condemnation of lands for other public purposes, and any officer or agent authorized by the United States may institute and conduct such proceedings in their behalf.