8 



are practically produced in their native country alone develop, no 

 more being produced. Japanese azaleas behave in much the same 

 way, but some plants have continued to flower a little annually. In 

 plants which behave in this way a strain might be obtained which 

 would flower as nearly as well as in cold climates by careful selec- 

 tion. Certain shrubs after some time when well grown produce a 

 few flowers, on new wood and then cease to flower again. Tibouchina 

 setnidecandra, a native of Brazil, was obtained from Kew a few years 

 ago as a small plant. It grew strongly and attained a height of 

 about six feet, and was propagated by cuttings, of these; two plants 

 produced their fine flowers once or twice and then ceased to flower 

 altogether. It has apparently done so before, for in the Herbarium 

 is a specimen from a cultivated plant prepared by Mr. Cantley, 

 but the plant had long ceased to exist in cultivation here, doubtless 

 for the same reason. 



The two abutilons of Christmas Island, raised from seed brought 

 myself, {A. and A. Lister i) grew to a great size fully as 

 healthily as any I saw in their native home. Both have flowered 

 but very sparingly, much more so than in Christmas Island. The 

 locality they inhabit is very xerophytic, and most of the local plants, 

 ferns excepted have failed to grow at all in our wet climate. 



Many exotic shrubs, however, flower very well and abundantly 

 but never set fruit ; such are Bigonia magnified, B. oequinoctialis, 

 Tecoma ceramensis, Odontadenia speciosu, Mussaenda erythro- 

 phylla, Bougainvilleas, Tecoma Curtiszi, Ipo?nea arborea, Allamanda 

 Cathartica [A. schottii and A. williamsi fruit regularly) and 

 Solatium maronieuse which has been already mentioned the causes 

 of these failures to fruit are not very clear. Some of the causes have 

 already been suggested, but there are many cases in which the 

 reasons are not obvious, as the reproductive organs are complete 

 and healthy and the plants regularly visited by insects. A plant 

 introduced from other countries frequently does not fruit the first 

 year apparently because it is not visited by insects, who do not seem 

 to find it out at first, but after a year or two it is regularly visited 

 by insects and produces fruits. 



The question next arises as to how we can acclimatize exotic 

 plants so as to make them available for the country into which they 

 have been introduced. We know little as yet concerning the physi- 

 ology and oecology of plants of the tropics. There have been but 

 few researches made into this subject. The facilities for this work 

 in the British Empire are very scanty, and there are nowhere labora- 

 tories or scientists employed in researches of this kind such as are 

 possessed by the Dutch at Buitenzorg or the Americans in Hawaii 

 and the Philippines. Much good work on certain lines have been 

 done in these establishments, but much of our knowledge of tropical 

 agriculture remains in the empirical stage. 



By careful selection we may obtain plants proof against the 

 diseases which prevent their cultivation, and we may obtain strains 

 suitable for cultivation under all classes of soil and climate. By 



