i9o8.] OF THE SAND DUNE PLANTS OF BERMUDA. 99 



action in scooping out the sand. These dunes form the setting upon 

 which the typical sand strand plants are distributed. 



Plant Distribution. — The upper beach at the foot of the dunes 

 is characterized by the presence of Cakilc ccqnalis, which shows a 

 more decided branching habit than the closely related species on the 

 coasts of the American continent, Cakile maritima. Besides this 

 plant, the botanist sees clumps of Tourncfortia gnaphalodes, Sccevola 

 Plumieri and Croton maritimus. The shrubs, however, grow most 

 luxuriantly on the slopes and summits of the dunes. Ipomcca pes- 

 caprce, as elsewhere in the tropics (Mexico, the West Indies), is a 

 typical plant of the upper beach ; in fact, the upper beach is char- 

 acterized by its presence, with its long runners growing down from 

 the slopes of the dunes out upon the flat, sandy beaches. On the 

 dune slopes in Bermuda it is associated with Sccevola Plumieri and 

 the crab grass, Stenotaphriim amcricanum. 



Back of the dune crests are found Tournefortia gnaphalodes, 

 Ipomcca pes-caprce, Sccez'ola Plumieri, Juniperns hermudiana (wind- 

 swept forms), Sisyrinchium hcrmudianmn, Lepidium mrgimcum, 

 Euphorbia huxifolia (a prostrate plant growing in rosettes), Cana- 

 vdia ohtusifolia (a leguminous vine) and the prickly pear cactus, 

 Opiintia vulgaris. On the dunes at Tuckertown, where the sand 

 covers the entrance to the natural arch, Sccci'ola Plumieri forms 

 extensive clumps in pure association. Solidago sempervirens, as in 

 the eastern United States, is also a dune plant, together with the 

 smooth and hairy forms of Borrichia arboreseens, Dodonaa viscosa, 

 a small tree with its varnished leaves, is also a tenant of the dunes. 

 The most interesting dune plant is Conocarpus erectus, which is a 

 typical mangrove tree growing with its roots affected by salt water. 

 In Bermuda, however, it occurs perhaps more frequently on the dry 

 upper slopes of the dunes. In one place on the south shore, it covers 

 nearly a quarter of an acre. The crab grass, Stcnotaphrum ameri- 

 caniim forms close mats on the lee side of the dunes. 



The high dunes on the south shore of the parish of Paget have 

 been invaded by a number of exotic plants, introduced by man into 

 the islands, such as Nerimn oleander, Lantana camara, L. crocea, 

 while Croton maritin^us, Canavalia ohtusifolia, Dodoncca viscosa, 

 Borrichia arboreseens and Passiflora suberosa are among the most 



