230 PLANTS, SEEDS, AND CURRENTS 



Before dealing with the means of dispersal of the wide-ranging 

 littoral species, Sccevola Plumieri and Sc. Kcenigii, reference may be 

 made to the genus in this connection. When in the Pacific the 

 writer formed the opinion that the inland species, though not fitted 

 for dispersal by currents, were well suited on account of their fleshy 

 drupes for dispersal by birds, his observations and experiments 

 indicating that only a littoral station was associated, as in the case 

 of Sc. Kcenigii, with the capacity for distribution by currents (Plant 

 Dispersal, p. 135, etc.). In this way, it was held, the range of such 

 a shore species was enormously extended as compared with the 

 inland species, nearly all of which were restricted to a particular 

 group of islands or were confined to small areas. 



Krause (p. 14) deals with the subject; but his inferences were 

 based entirely on the structural characters of the fruits. He con- 

 siders that the fruits of Sccevola are adapted for two methods of 

 dispersal — one by birds and other animals when the fruit has a fleshy 

 covering and a hard endocarp, the other by currents where the 

 endocarp has a cork-like outer layer suggestive of buoyancy in the 

 fruit. In illustration of dispersal by currents he takes four West 

 Australian species of dune plants growing on and near the coast, as 

 well as Sccevola Kcenigii, the widely ranging strand plant of the Old 

 World ; but no results of experiments are given and none are referred 

 to, since they did not come within the scope of the work. Amongst 

 examples of dispersal by birds he mentions the strand plant of the 

 New World and of both the African coasts, Sccevola Plumieri, for 

 the fruits of which only dispersal by birds seemed possible, the 

 agency of the currents being excluded. I formed the same opinion 

 on first examining these fruits in the West Indies, but experiments 

 showed that they are also well fitted for distribution by the currents. 



The two modes of dispersal of the fruits of Sccevola have long been 

 established by Schimper, myself, and other students of distribution. 

 They may be combined in the same species, as with the two world- 

 ranging beach plants Sc. Kcenigii and Sc. Plumieri, the juicy exocarp 

 attracting the bird, and the buoyant stone fitting the fruit for trans- 

 port by the currents. Schimper first apportioned their true values 

 to these two capacities in the same species when in the case of Sc. 

 Kcenigii, in his book on the Indo-Malayan strand flora (p. 156), he 

 regarded the fruits as fitted for dispersal over long distances by the 

 currents and for short distances by birds. The fruit is specially 

 described and figured in his work (p. 172). 



Yet it is evident from the treatment of Sccevola by Krause in this 

 monograph that the greater number of the species have dry or hard 

 fruits that would not be especially attractive for birds. In this 

 connection it is very significant that the two sections, Sarcocarpcea 

 and Xerocarpcea, which derive their names respectively from the 

 fleshy and from the dry character of the fruits, include in the case 

 of the first named the species that are established in localities farthest 

 away from the Australian home of the genus, and in the case of the 

 second named nearly all the species of the genus that are confined 

 to Australia. The section Sarcocarpoea includes not only the inland 

 species that have established themselves through the agency of 



