Bahaman Region: Floridan Area. - 697 
The most interesting strand plant of the open beaches of the keys along 
the mainland is Agave decipiens widely distributed along the strand of tropic 
Florida, being disseminated almost wholly by bulblets produced in place of 
flowers. On sandy stretches occur Aymenocallis caymanensis, Coccoloba ,‚ Ipo- 
moea, Ernodes and Alternanthera floridana. 
ShellBank Formation. On the seaward side of mangrove islands shell banks are formed 
by the action of the tides and waves and these become occupied by vegetation which consists 
of Forestiera porulosa, Myrsine rapanea (= Rapanea guyanensis), Coccoloba uvifera and Juniperus 
virginiana with Iva imbricata, Cakile maritima and Ipomoea pes-caprae at the margin of the water. — 
e shell islands of the coast consisting of oyster shells are inhabited by Yucca aloifolia, 
Forestiera porulosa, Quercus virens (= Q. virginiana), Opuntia pes-corvi, O. vulgaris, Mentzelia 
floridana, and Vincetoxicum scoparium climbs over these plants while Passiflora suberosa and 
Coceulus carolinus carpet the pavement of white shells. Chiococca racemosa and Psychotria rufes- 
cens also occur?). 
Cypress Swamp Formation. This formation is found in many parts of 
southern Florida, but nowhere better developed than in the Big Cypress 
Swamp west of the everglades and limited on the gulf side by the mangrove 
swamps which fringe the coast. It can be located by its proximity to Galli- 
vans Bay and Cape Romano. The southeastern limit of Taxrodium disti- 
chum, the principal tree of this formation, has been placed by Professor 
SARGENT at Mosquito Inlet (about lat. 29°) on the east coast and at Cape 
Romano (about lat. 26°) on the west coast, but SMALL has found it extending 
down the Miami River and has found it in the everglades nearby. 
Little is known of the composition of this formation in Florida. The larger and smaller 
trees form with the lesser vegetation an almost impassable growth. . The larger trees are buttressed 
and large root growths the so-called “knees” project from the soil or above the surface of the 
water. This forest is so dense that perpetual twilight is found beneath the trees and the silence 
is relieved only by the occasional splash of an alligator in the streams which sluggishly meander 
through the depths of the forest. 
Everglade Formation. The everglades historically speaking may be older 
than the pine woods. Their origin is as follows °): 
The chain of keys surrounded by the everglades are duplicated by the 
outer series of Florida keys. Before these everglade hammock islands were 
raised to their present altitude, they were probably surrounded by a shallow 
sea. This being the case, we can easily account for the tropic American flora 
now inhabiting them. After sufficient elevation had taken place, the surroun- 
ding sea was transformed into the vast spring known as the everglades and 
a northern flora advanced into this area thus surrounding and isolating a 
totally different tropic flora. (See ante Part II, page 201, 229.) 
The everglades cover an area about one hundred miles wide and perhaps 
one hundred and fifty miles long, the elevation being about eighteen feet above 
I) Currıss, A. H.: A Visit to the Shell Islands of Florida. Botanical Gazette IV: 117, 132, 
154. See also Bibliogr. p. 67. , 
2) HARSHBERGER, JOHN W.: The comparative Age of the different floristic Elements of RRER 
North America. Proc. Acad. Nat. Se. Phila. 1904: 613. — SMALL, J. K.: Southern ee 
(1907) see Bibliogr. p. 92. 
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