1891.] D. Prain— T/ie Vegetatio7i of the Coco Group. 383 



be put down in the list of sea-introduced species ; they are well-known 

 as weeds of cultivation elsewhere, being diffused because of the readi- 

 ness with which the indehiscent segments of their fruits attach them- 

 selves to the clothes of man and to the fur of his domestic animals. 

 Here they are undoubtedly not weeds introduced by man, but it may 

 well be that they have been introduced by birds, owing to fragments 

 of their pods having attached themselves to their feathers. Another 

 species to which the same remai-ks apply is Adenostevima viscosum, though 

 this is more probably sea-introduced than the other ; still another is Boer^ 

 haavia repens ; perhaps all four are distributed at one time by the sea, at 

 another by birds. Lippia nodijl.ora may also be a bird-introduced species ; 

 its seeds may have been brought in the pellets of mud that become 

 attached to the feet, and to the feathers at the base of the bill of 

 wading- and swimming-birds. Achyranthes porphyristachya which, from 

 its situation in these islands, cannot be a weed introduced by mau, and 

 which is a common sea-shore species in the Nicobars and in the 

 Laccadives also, may perhaps be bird-introduced like the JDesmodia. 

 If, as is suggested, now one agency, now another is responsible for 

 the dispersal of these species, it is easy to understand why those 

 species should all be " littoral " in these islands and yet occur as 

 inland species in other localities. Mucuna gigantea will be readily 

 admitted as an unequivocal example of this mode of distribution, 

 as will Derris sinuata, for both occur in the beach-forest more com- 

 monly than they do on the ridges ; so too, will the other Leguminosce of 

 the list except pei"haps Entada scandetis. And yet Entada scandens 

 must be sometimes an introduced species, for it is one of the plants 

 that occur on JN"arcondam, an island for which it seems impossible to 

 postulate any previous land-connection ; the writer moreover had the good 

 fortune to find one of its enormous seeds germinating along with those 

 of Mucuna, etc., on the sandy islet between Great Coco and Jerry. 



Physalis minima is a species that at first suggests bird-introduction 

 rather than sea-introduction, and its wide inland dispersal undoubtedly 

 is largely owing to its fruits being eaten and to the subsequent voiding 

 of its hard discoid seeds. But here it is only found close to the sea just 

 above the spray-line and its fuits were found in the " drifts " here and 

 there, the light bladder-like calyx amply accounting for their flotation ; 

 the pulp of the fruit probably protects the seeds, if such protection be 

 necessary, from the action of the salt water. Among the Gonvolvidacece, 

 for which this means of dispersal is not at all uncommon, the only species 

 now included that calls for remark is Convolvulus parviflorus. It is, 

 however, one of the commonest of the sea-face creepers along the west 

 coast of Great Coco, and is equally common on Narcondani, Barren 



