TOPOGRAPHICAL, ECOLOGICAL AND TAXONOMIC NOTES. 345 



On tliis slope a number of Norfolk Island Pines have been 

 planted, the lowermost row on the strand at its base, all 

 •of which are in a flourishing condition. 



On the broken verge of the bank the usually solitary 

 plants of Euphorbia Sparmanni have, in several instances, 

 become confluent and cap the crown of a knoll or the crest 

 of a ridge. In a shallow depression Sccevola suaveolens 

 has massed a carpet measuring 18 x 24 feet. The succulent 

 stemmed Plectranthus parviflorus Henck., frequently an 

 epiphyte on mossy rock benches or Fern and Orchid strewn 

 boulders in the deep shade of the forest, is exceptionally 

 robust on the exposed dune plateau where the sunlight is 

 unbroken. It also makes a sturdy growth in the soil 

 pockets on the ocean escarpment, displaying in a marked 

 degree its appreciation of this halophilous environment, 

 though it includes the dual disabilities of exposure and 

 extreme insolation. 



On the southern end of the beach, in the shallow sluggish 

 seepage flowing across the strand from the swamp at the 

 rear of the dune, a colony of Carex pumila has been invaded 

 by the introduced Hydrocotijle umbellata var. bonariensis. 

 On the strand the Carex is dominant, but as the channel 

 narrows and deepens and its salinity decreases on its inland 

 course, the Hydrocotyle assumes supremacy, closing up 

 its ranks and lengthening the stalks of its umbrella-like 

 leaves, holding the blade aloft in a horizontal position. 

 This formation presents such a complete barrier to the 

 entrance of light, that competition from the surrounding 

 aquatic herbage is effectively suppressed. A plant of 

 Kennedya rubicunda has ventured into the swamp, display- 

 ing exceptional plasticity in an entirely novel habitat. 

 Though its root system and the lower portion of its stem is 

 submerged, the emerged stem and branches have produced 

 a robust growth, which festoons a considerable area of a 

 shrubbery of Viminaria denudata. 



