SKETCH OF THE CHARACTER OF THE MARINE ALGAL VEGETATION OF 

 THE SHORES OF THE GULF OF MEXICO 



By Wm. Randolph Taylor, University of Michigan 



GENERAL NATURE OF THE FLORA 



The warm tropical current from Central America 

 sweeps between Cuba and Yucat&n to find its 

 way into the Atlantic between Florida and Cuba 

 or to swing into the Gulf of Mexico. With this 

 as a striking feature of the environment, it is 

 natural to expect, and to find confirmed in fact, 

 that the marine algal flora is altogether tropical 

 in character. Countercurrents alongshore do not 

 carry northern plants southward. Where species 

 known in the north are found here, they are 

 ubiquitous types which range widely into the 

 American tropics. Though much of the coast with 

 which we are concerned is above the Tropic of 

 Cancer — indeed all of the United States coast — 

 where the land climate is no more than subtropical, 

 this does not alter the character of the marine 

 vegetation. The tropical currents from the south- 

 east determine what species can migrate here, and 

 the limited physical variety of much of the shore 

 determines what species establish themselves. One 

 may justly contrast the conditions at the Bermudas 

 which, though in a much more northern latitude, 

 are affected by the northward effluent stream 

 through the Straits of Florida and have a highly 

 varied shoreline and a similar, though much richer 

 and more diverse, tropical marine vegetation. 



Within our range one may generalize by saying 

 that the most varied algal flora exists on the eastern 

 shores, the Florida Keys certainly, and probably 

 Cuba and Yucatan, and that as one progresses 

 toward the north the flora becomes simpler and 

 less spectacular. This is due, in part, to the phys- 

 ical nature of the shore, in part to the somewhat 

 lower water temperatures and lower concentration 

 of nutrient materials, and in part, at least locally, 

 to the dilution of the sea water by the great 

 rivers which empty into the Gulf in this sector. 



MARINE BOTANICAL STUDIES OF THE 

 GULF OF MEXICO 



Studies of the algae of the shores of the Gulf 

 have been so very few that, alone, they would 



hardly serve as a useful base of reference for the 

 beginner. Nevertheless, they are adequate to 

 show the main peculiarities of the flora, and by 

 supplementing these lists with the more compre- 

 hensive literature of the West Indian islands one 

 may approach the identification of Gulf algae with 

 confidence. 



Bounding our area on the east lies the Florida 

 Peninsula and its appendage of keys. The eastern 

 coast of this and the keys have been given quite a 

 little attention. The first significant list of the 

 algae of Florida is that of Bailey (1848) which was 

 amplified and made much more useful a few years 

 later by the illustrated volumes of Harvey (1852- 

 58) and the more complete list of Farlow (1875). 

 The bulk of the information to which this develop- 

 ment was due came from the collection of Mrs. 

 F. A. Curtiss (A. H. Curtiss, 1899) and Mrs. G. A. 

 Hall who collected extensively and sent valuable 

 series of plants to Harvey, Farlow, Collins, and 

 experts abroad. Murray (1888-89), in bringing 

 together aU the lists of West Indian algae, included 

 many references to those of Florida, and Collins 

 et al., in their exsiccata (1895-1919) and his 

 account of American Chlorophyceae (1909-18), 

 greatly enhanced our knowledge of Florida algae. 



However, it is obvious that these coUections 

 and records were of east-coast observations; 

 though they include Key West, they give us 

 practically no knowledge of the flora of the Gulf 

 side of the peninsula. The writer (1928) was able 

 from his study of the algae of the Dry Tortugas to 

 greatly amplify the records from the Florida Keys 

 in an area as much related to the Gulf as to the 

 Straits of Florida, but only in a later (1936) paper 

 did he specificaUy treat of a few west Florida rec- 

 ords. Nielsen and Madsen (1949a, b) and Madsen 

 and Nielsen (1950) have recently extended con- 

 siderably the records of northwest Florida species. 



Westward to Texas the coastal flora is essentially 

 unknown. There are no lists of importance and 

 only occasional mention of algae in botanical 

 works (Cox 1901, Taylor 1936). The Texas 



177 



