450 



APPENDIX 



From experiments made on the fruits of Atriplex portulacoides 

 growing at Salcombe in South Devon (see Note 38 of the Appendix), 

 it was evident that whilst the seed-like fruit sinks it can float when 

 surrounded by the perianth between two and four weeks, buoyed up 

 doubtless by air-bubbles. It thus might easily have been carried 

 iby the sea to the Canary Islands from the adjacent continental 

 -coasts. On the other hand, in the case of Beta maritima, which occurs 

 ■in Madeira and in the Azores as well as in the Canaries, the direct 

 : action of the currents must be excluded, since the buoyancy of the 

 fruit is limited to a day or two (Plant Dispersal, p. 542). Three 

 other of the shore plants of this group, Euphorbia paralias and the 

 two species of Frankenia, may here be noticed from the standpoint 

 of dispersal. The seeds of the first named float for a long time 

 unharmed in sea- water (Ibid., p. 543) ; whilst the very small seeds of 

 Frankenia are probably distributed by birds. 



Note 7a (p. 10). 

 The plant-stocking of islets in the Florida Sea, 



One of the most methodical series of observations on the stocking 

 of islets in coral-reef regions with plants are those made by Mr. 

 Lansing (junior) in 1904 on the sand-keys of Florida to the westward 

 of Key West. He had been commissioned by the Field Columbian 

 Museum of Chicago to carry out this inquiry. He collected speci- 

 mens of everything he saw, noting carefully the plant arrangement 

 in each islet, and laying down his results on maps made on the spot. 

 His collections, together with his comprehensive notes and maps, 

 supplied materials for a detailed consideration of the flora of these 

 islets in a paper by Dr. Millspaugh published by the Museum in 1907. 

 " As was to be expected " (to quote from this paper), " this archi- 

 pelago proves to be vegetated with only the usual broad strand 

 species common to similar situations on the Antillean islands in 

 general." In discussing the results Dr. Millspaugh brought to bear 

 an experience derived from a wide field of study of insular and 

 strand formations in the Antillean region. The value of this paper 

 for us lies in its illustrating the process of plant-stocking in the case 

 of newly formed low islets in the West Indies. 



These sand-keys vary greatly in size, the smaller being usually 

 from thirty to a hundred yards long, whilst the larger may measure 

 .a mile or more. Their elevation is generally two to four feet ; but it 

 may be as low as one foot and as high as nine feet. Of the nineteen 

 keys examined only three exceeded four feet. The numerous small 

 .keys, consisting exclusively of mangrove colonies, are not specially 

 *dealt with in this paper. They, however, represent the earliest stage 

 iin the plant- stocking process. My remarks here will be mainly 

 (restricted to a consideration of these results from the standpoint 

 supplied by my observations and experiments on the coral islets of 

 the Indian and Pacific Oceans, as well as by those on the small cays 

 of the Turks Group in the West Indies. In so doing I shall as a rule 

 be following Dr. Millspaugh's guidance, though in my own fashion. 



