138 



Papers from the Department of Marine Biology. 



List of Submerged Spermatophytes and Algce in the Gulf of Mexico about Tortugas. 

 ORDER NAIAD ALES. ALG^E continued. 



Cymodocea manatorum Ascherson. Mana- 

 tee-grass. 



ORDER HYDROCHARITALES. 



FAMILY ELODEACE.E. 



Halophila engelmannii Ascherson. 

 Halophila baillonis Ascherson. 



FAMILY HYDROCHARITACE^E. 



Thalassia tesludinum Koenig and Siins. 

 Turtle-grass. 



ALG.E. 



CYANOPHYCEjE. 



Lyngbya majuscula (Dillwyn) Harvey. 

 CHLOROPH YCEyE . 



Caulerpa sertularioides (Gmelin) Howe. 



prolifera (Forskal) Lamarck. 



racemosa (Forskal) Agardh. var. 



occidentalis (J. Agardh.) Borgesen. 



ashmeadii Harvey. 



crassifolia (Agardh.) J. Agardh. 

 C odium tomentosum (Hudson) Stackhouse. 

 Penicillus dumetosus (Lamarck) Decaisne. 

 Udoteaflabellum (Ell. and Sol.) M. A. Howe. 

 cyathiformis (Decaisne) Howe. 



CHLOROPHYCE.E continued . 



Halimeda simulans M. A. Howe. 



tuna (Ellis and Solander) Lamarck 

 tridens (Ellis and Solander) La- 

 marck. 



opunlia var. minor (Ellis and Sol- 

 ander) Lamarck. 

 Valonui ventricosa L. 



Dictyosphceria favulosa (Agardh.) Decaisne. 

 Acetabularia cremdata Lamaroux. 



PH<EOPHYCE/. 



Dictyopteris justii Lamarck. 

 Zonaria lobata A. K. Agardli. 

 Padina pavonia (L.) Gaillon. 

 Sargassumnatans (L.) Meyer S. bacciferum. 



RHODOPHYCE.E. 



Hypnea muscoformis (Wulfen) Lamarck. 

 Acanthophora spicifera Vahl, A. thierii 



Lamarck. 



Lawrencia obtitsa (Hudson) Lamarck. 

 Galaxaura flagelliformis Kjellman. 

 Wurdemannia setacea Harvey. 

 Corallina rubens L. 

 Gracillaria confervoides (L.) Greville. 



CONCLUSION. 



In this treatment of the species in the Tortugas it has been aimed to 

 give some idea of the character of the dry-climate plants inhabiting 

 these islands, their distribution, and particularly the changes which 

 have occurred on the various keys since Lansing's survey, with an 

 attempt to analyze the reasons for such changes. This, it is hoped, has 

 been done, with the help of herbarium specimens collected and living' 

 plants sent north to the University of Pennsylvania Botanical Garden, 

 and also the extensive field-notes and laboratory experiments made by 

 the writer during his residence of two summers in these islands. 



