FEB. 1907. FLORA SAND KEYS OF FLORIDA MILLSPAUGH. 223 



MARQUESAS "I" 

 MARCH 12, 1904 



f Avicennia nitida (2256) 



< Borrichia arborescens (2257) 



(^ Cenchrus tribuloides (2264) 



c- Conocarpus erecta (2259) 



Cyperus brunneus (2262) 



Euphorbia buxifolia (2263) 



tf Euphorbia havanensis (2265) 



^ Eustachys petraea (2255) 



$ Iva imbricata (2253) 



X Rhizophora mangle (2258) 



f Suriana maritima (2261) 



I Uniola paniculata (2254) 



/ Waltheria americana (2260) 



A small sand strip about 100 feet in length, 25 feet wide, and less 

 than 2 feet in elevation. Its seaward shore is too abrupt for a Sfsu- 

 vium colony, or has been recently eroded to such an extent as to have 

 lost it. The immediate brow of the bank is given over to the usual 

 Uniola- Euphorbia association in which the ample admixture of Suriana 

 so near the brink proves with near certainty the erosion of this shore.. 

 The colonization of the plateau is quite distinctive in its novel associ- 

 ation of Eustachys and Waltheria. This association appears to have 

 weaned the Cyperus element away from the Uniola association, which 

 in turn has adopted Cenchrus as a substitute. The mangrove border, 

 while retaining a complete fringe of Avicennia, here shows for the first 

 time in the group a full substitution of Conocarpus for Laguncularia^ 



