1908] OF THE SAND DUNE PLANTS OF BERMUDA. 109 



of the palisade cells. Therefore it is a diplophyll (Fig. ly, 

 Plate III.). 



Bibliography. — Little has been published on the structure of 

 the dune plants of tropical America. The following papers are 

 in part a contribution to our knowledge of the microscopic struc- 

 ture of the strand plants of the American tropics. A few of the 

 sand dune plants are of cosmopolitan distribution and they are? 

 therefore, described as to their morphology in the classic work 

 of A. F. W. Schimper, " Die indo-malayische Strandflora," pub- 

 lished as the third volume of " Botanische Mittheilungen aus den 

 Tropen " in 1891. Thomas Kearney in 1900 published in the Con- 

 tributions from the U. S. National Herbarium (V., Xo. 5) an 

 important paper on " The Plant Covering of Ocracoke Island ; A 

 Study in the Ecology of the Xorth Carolina Strand Vegetation." A 

 chapter is devoted to the histological structure of the plants. The 

 only plants which concern us are Yucca aloifolia, Croton maritimus, 

 Borrichia frutescens, which are common also to the Bermuda strand. 

 F. Boergesen and Ove Paulsen make a contribution to " La Vegeta- 

 tion des Antilles Danoises " in Revue Generale de Botanique (Tome 

 XII., 1900), in which they discuss with figures the microscopic 

 structure of a few of the typical strand plants. As throwing con- 

 siderable light on the problems concerned in this paper on the Ber- 

 muda strand flora reference should be made to these works of 

 general import to the botanical questions involved. 



Diels, L. 



Stoffwechsel und Structur der Halophyten, Jahrbiicher fiir wissen- 

 schaftliche Botanik XXIII. : 309-322, 1898. 



Schimper, A. F. W. 



Pflanzengeographie auf physiologischer Grundlage, 1898. 

 Solereder, H. 



Systematische Anatomie der Dicotyledonen, 1898-99. 

 Warming, E. 



Halofyt Studier, Memoires de 1' Academie Royale de Danemark, ser. 6, 

 VIII., No. 4, 1897. 



