FEB. 1907. FLORA SAND KEYS OF FLORIDA MILLSPAUGH. 225 



TORTUGAS GROUP 



The islets of this group, the most western of the Florida Keys, 

 are too shifting, or lacking in coral mud, to form an anchorage for 

 Rhizophora mangle, in this respect differing radically from the man- 

 grove-formed Marquesas group, from which they are separated by over 

 fifty miles of open sea. Long* and Middle Keys are so low as to be 

 awash during heavy weather and, on this account, are void of vege- 

 tation. The details of the vegetation of the other keys of the group 

 are as follows: 



EAST KEY 

 MARCH 21, 1904 



A Cakile fusiformis (2492) 

 cf Cenchrus tribuloides (2487) 



Euphorbia buxifolia (2485) 

 $ Iva imbricata (2484 and 2486) 

 D Scaevola Plumieri (2489) 



Sesuvium portulacastrum (2490) 

 % Tournefortia gnaphalodes (2491) 

 I Uniola paniculata (2488) 



East Key lies about four miles north of east from Garden Key. 

 It is little more than a mere sand bank about 280x50 feet in area. I*s 

 west shore is narrow and rises abruptly to an elevation of about 2 feet, 

 whence the surface slopes gradually to broad strands on the east and 

 south. 



The vegetation consists principally of Cenchrus and Euphorbia 

 with a sprinkling of Uniola at the southern end; two isolated patches 

 of Sesuvium near the center of the islet; and the few other species 

 scattered without definite association. 



