220 PLANTS, SEEDS, AND CURRENTS 



Tobago, etc. ; and, as in the Turks Islands and elsewhere, seedlings 

 that had raised themselves from stranded seeds were observed grow- 

 ing in the beach-drift. 



I have been obliged to omit, on account of the limits of space, a 

 very long note of many pages on the distribution of this plant in the 

 warm latitudes of the globe as compared with Convolvulus soldanella, 

 which takes its place on the beaches of temperate latitudes. As a 

 rule, Ipomoea pes-caproz monopolises the coasts between the 30th 

 parallels of north and south latitude, whilst Convolvulus soldanella 

 holds the shores of the temperate zones beyond those latitudes in 

 both the north and south hemispheres, though in the New World 

 wide gaps may separate the two species. As far as I know at present, 

 the ranges of the two species only overlap in Australia. It has long 

 been known from the observations of Cheeseman that the two plants 

 meet in the neighbouring Kermadec Group (lat. 31° 30' S.), and it 

 would, therefore, be expected that the two plants would overlap on 

 the eastern coasts of Australia. Mr. Maiden very kindly looked up 

 the matter in my interests, and the conclusion he formed was that 

 44 the two species overlap in northern New South Wales and in 

 southern Queensland for at least 300 miles." Looking at the data 

 which he supplied me it would be fair to conclude that the over- 

 lapping takes place between the 25th and the 32nd parallels, Ipomoea 

 pes-caproe reaching south to 32° S. and Convolvulus soldanella extend- 

 ing north to 25° S. New Zealand, a home of C. soldanella, is well 

 outside the zone of /. pes-capro3 and does not possess it. Prof. Ewart 

 also supplied me with some valuable information on this point. 



The comparison has opened up so many problems of distribution 

 in different parts of the world that it would take more space than can 

 be allotted in these pages to deal satisfactorily with the subject. 

 When I have filled up the numerous lacuna? in my research, I hope 

 to publish it in the form of a paper. A short discussion of the ques- 

 tion is given in my previous work on Plant Dispersal in Note 49 of the 

 Appendix. 



Ipomcea tuba, Don. 



According to the various authorities at my disposal this plant is 

 confined to the warm latitudes of the New World, where it is widely 

 distributed, as in South Florida, the Bahamas, the Greater and 

 Lesser Antilles, reaching south to the Guianas and Brazil. Urban 

 regards it as almost cosmopolitan in the warm regions of the globe 

 (Symb. Antill., IV., 513) ; but he seems nearly alone in holding this 

 view. Though not known from the Bermudas, it was found both 

 by Moseley and Ridley on the small Fernando Noronha group lying 

 about 200 miles off Cape St. Roque (Chall. Bot., III., 19 ; Journ. Linn. 

 Soc. Bot., vol. 27). 



Particulars as to its station are often lacking; but it is evidently 

 as a rule a maritime plant, and in the manuscript of the Bahamian 

 flora lent to me by Dr. Millspaugh it is described as a denizen of 

 sandy shores in that archipelago; but I do not gather that it ever 

 intrudes on the beach after the fashion of Ipomoea pes-caprce. Thus 



