XXII 



THE TREE-LOBELIAS 



255 



their antiquity and degree of differentiation. According to my 

 view, the first Hawaiian Lobeliaceae occupied open, exposed 

 localities such as are held by the decadent genus Brighamia now, 

 and acquired their monstrous form in the humid forests of a later 

 age. (See Perkins in Note 80.) 



In his monograph on the Campanulaceae (Engler's Nat. Pflanz. 

 Fam., teil 4, abth. 5, 1894), S. Schonland, speaking of the sub- 

 family Lobelioideae, places the seven endemic Hawaiian and 

 Tahitian genera in a group by themselves. Though, as he 

 observes, the Hawaiian tree-forms appear at first sight to consti- 

 tute a natural group, they cannot be sharply distinguished from 

 other forms, and even in habit come near some Indian and 

 Abyssinian types of Lobelia. In their treatment, he says, they 

 should all go together, and he does not approve of the endeavours 

 of some botanists to isolate one of them (Brighamia) from the rest 

 and to connect it with the Australian genus Isotoma. 



It is also to be noted that whilst four of the Hawaiian genera 

 are more or less dispersed over the group, one (Brighamia) with 

 only one species is confined to the islands of Molokai and Niihau, 

 the double habitat being suggestive of its approaching extinction. 

 Another (RoUandia) with six species is restricted to the island 

 Oahu. Cyanea, which possesses twenty-eight out of the total 

 of fifty-eight species, may, from the point of view of its formative 

 energy, be regarded as in its prime. It is thus apparent that, as 

 with the Compositae, the early Lobeliaceous immigrants were not 

 all contemporaneous arrivals. 



Another interesting fact of distribution, brought out by an 

 analysis of Hillebrand's materials and illustrated in the subjoined 

 table, is that out of the fifty-eight Hawaiian species, all of which are 



DISTRIBUTION OF THE LOBELIACEAE IN THE HAWAIIAN ISLANDS.* 



* All the species are endemic. 



endemic, thirty-eight, or 66 per cent., are recorded from only one 

 island. In most of the other cases they are recorded from two or 



