INSULAR PLANTS AND INSECTS. 275 



an indefinite period. Such is probably the explanation 

 of the Pelargonium of Tristan d'Acunha, which forms 

 masses of bright colour near the shore during the 

 flowering season ; while most of the other plants of the 

 island have colourless flowers in accordance with the 

 almost total absence of winged insects. The presence 

 of many large and showy flowers among the indigenous 

 flora of St. Helena must be an example of a similar 

 persistence. Mr. Melliss indeed states it to be " a 

 remarkable peculiarity that the indigenous flowers are, 

 with very slight exceptions, all perfectly colourless ; " 

 but although this may apply to the general aspect of 

 the remains of the indigenous flora, it is evidently not 

 the case as regards the species, since the interesting 

 plates of Mr. Melliss's volume show that about one 

 third of the indigenous flowering plants have more or 

 less coloured or conspicuous flowers, while several of 

 them are exceedingly showy and beautiful. Among 

 these are a Lobelia, three Wahlenbergias, several Com- 

 positse, and especially the handsome red flowers of the 

 now almost extinct forest-trees, the ebony and redwood 

 (species of Melhania, Byttneriaceae). We have every 

 reason to believe, however, that when St. Helena was 

 covered with luxuriant forests, and especially at that 

 remote period when it was much more extensive than 

 it is now, it must have supported a certain number of 

 indigenous birds and insects, which would have aided in 

 the fertilization of these gaily- coloured flowers. The 

 researches of Dr. Hermann Mtiller have shown us by 

 what minute modifications of structure or of function, 

 many flowers are adapted for partial insect and self- 



1 Melliss's St. Hel&w, p. 226, note. 



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