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FREE INSTITUTE OF SCIENCE 
VEGETATION OF SOUTH FLORIDA a 
Smilax Beyrichii Kunth and Smilax bona-nox L. also clamber over the shrubs 
and trees of this area, and Jacquemontia reclinata House is a trailing vine, 
while such fleshy-stemmed cactaceous plants as Acanthocereus pentagonus 
(L.) Britt. and Rose, Opuntia austrina Small suggest on a hot, bright day the 
desert flora of America and hence the name, Litorideserta, applied by Brock- 
mann-Jerosch and Riibel to such a region, is appropriate. The spurge-nettle, 
Cnidoscolus stimulosus (Michx.) A. Gray, may be included in this category. 
A succulent herb, Sesuvium portulacastrum L., forms prostrate growths in 
the more open sandy stretches. The filling herbs, those that have no im- 
portant biologic significance but simply grow between the more conspicuous 
shrubs and herbs and fill the spaces between them, are Remirea maritima Aubl., 
Raimannia humifusa (Nutt.) Rose, Gerardia purpurea L. [=Agalinis purpurea 
(L.) Pennell], Borrichia frutescens (L.) DC., Cirsium pinetorum Small, and 
Helianthus debilis Nutt. The dune complex, as far as the writer was able to 
discover, does not exist on Sanibel Island. The thicket formation meets the 
vegetation of the upper beach on both the bay and Gulf shores. 
THICKET FORMATION 
The stable, captured, or stationary dunes of Anastasia Island, called 
fossil dunes by some authors, are covered with a thicket, which, near the 
outer dune complex of shifting, or unstable, dunes, is a low thicket, or 
Krummholz of wind-swept oak trees with dead branch tips projecting upward 
above the living ones. The interlocking of the upper branches produces low, 
round-headed clumps of trees, which are usually massed together, or in some 
places they are separated by intervals of lower bushes or by exposed stretches 
of sand. Looked at from the top of Anastasia light-house (50 meters high), the 
bushland has a prevailing gray-green tone, and with the rounded tops of the 
trees a general billowy appearance. The general gray-green color scheme, how- 
ever, is broken by dark-green patches of Juniperus (Sabina) virginiana L., 
Sabal palmetto (Walt.) R. and S., bull-bay, Magnolia foetida (L.) Sarg., and 
holly, Ilex opaca Ait. These dark-green areas provide a striking contrast to 
the gray-green colors of the gnarled, broad-headed oaks and other shrubs. 
The maqui of the Mediterranean, a form of coastal bushland, is strongly sug- 
gested by the thicket vegetation of the Florida coast and is related closely to 
the Mediterranean xerophytic evergreen scrub. How close the relationship 
may be ecologically future investigation will show. 
