122 Papers from the Department of Marine Biology. 



which add conspicuous features to the landscape and perhaps have 

 an influence on the native flora by producing shade and conserving 

 water, etc. Examples of these are the coconut palms, the Casuanna 

 trees, the papaws, and the figs planted about the building and gardens 

 of the light-house and laboratory; others are the Hymenocallis, the 

 oleanders and Hibiscus, Thespesia, aloes, yuccas, Pedilanthus, and 

 Asparagus. All of these, but more particularly the coconuts, papaws, 

 casuarinas, and Hymenocallis, have been liberally planted about the 

 laboratory grounds. A noticeable effect of these introduced plants was 

 the increase in the number of plants and the size and vigor of the foliage 

 in Boerhaavia viscosa when it grew under these trees or tangled among 

 the Hymenocallis plants along a concrete walk leading to the wind- 

 pump shed at the laboratory. Another example was seen in the greater 

 luxuriance of Chamcesyce and Ipomcea, when growing near the slight 

 shade thrown by the coconuts, the newer shoots of Ipomcea being more 

 slender and tender than when growing in their accustomed habitat on 

 the beach in fierce sunlight. These introduced plants, with the excep- 

 tion of the Cocos and Hymenocallis, have been brought in and planted 

 by the Director of the Laboratory and have (plate 4) maintained 

 themselves fairly well in such a difficult environment, although only 

 Casuarina has reproduced and seeded in. This Australian plant seems 

 to thrive remarkably in these islands. The Hibiscus about holds its 

 footing when planted, but Thespesia and Carica seem to decline if 

 not watered artificially. 



An interesting point in a study of the Loggerhead flora is the 

 comparison of Lansing's maps with the present ones. According to 

 Lansing, the island was mainly occupied by bay cedar. Millspaugh 

 also mentions this fact, 1 and states: 



"Its central plateau, like that of Bird Key, is entirely implanted with a pure 

 Suriana group, the individuals of which are about 6 feet high. The vegeta- 

 tion of the islet presents no association whatever, all its species being ele- 

 mentally scattered subtropic, maritime 'weeds.' Even the usually associated 

 Uniola and Euphorbia [Chamcesyce] appear as far separated as the limits of the 

 surface will allow." 



The author is convinced that Lansing overlooked the old patches of 

 Opuntia hidden in the dense growth of Suriana, as well as the very old 

 groups of sisal, but aside from this the appearance of the island is much 

 changed in the past 12 years. The spurge, Chamcesyce buxifolia, has 

 not changed its position or quantity, but the Uniola is now found with 

 it in its station on the northwest corner of the island as well as along the 

 east shore, and very plentifully on the southwest shore. Iva imbricata 

 seems now to have disappeared from Loggerhead. Portulaca, now as 

 then, is found only around buildings both at the light-house and also at 



Millspaugh, C. F., Flora of the Sand Keys of Florida. Field Columbian Museum Publication 

 118, Bot. Series n, No. 5. 



