45 



the most poisonous West Indian plants. While the species of Isotonta are small 

 herbs, BriglKnnia attains a height of twelve feet, but is fleshy throughout. Brig- 

 hamia is in all probability a nuich more recent immigrant that has established 

 itself in these islands, but not sufficient time has elapsed for it to expand and 

 to produce varieties and species. Only a single form differing from the species 

 in the orange yellow flowers has been reported so far. It probably was next 

 to Lohclia the last of the Lolielioideous immigrants to arrive in Hawaii; it is 

 safer to assume this than to say that the genus is a decadent one and that Brig- 

 Itaiiiia IS the last survival of the Isotoma-Brighaiiua tribe. Undoubtedly Brig- 

 liainia was handicapped l)y the restricted area which it found suitable for its 

 existenc'i and development 



Intermediate between Urigluimia and Isotonia is Apctaliia Raiateensis, a 

 remarkable arborescent species peculiar to the island of Raiatea; the generic 

 laame being derived from the native name ApefaJii. It is remarkable on account 

 of its unilocular ovary and parietal placentas. The long floral tube is split to 

 the base as in Isotoma, and the flowers are also single, while in Brlglianiia the 

 corolla is salver-shaped, and the flowers are arranged racemosely. 



In viewing the Hawaiian Lohelioideae, and their possible country of origin 

 we find that they must have been derived from four continents. The baccate 

 genera, Cyanea, Clcrmontia, DeUssca and Rollandia show a strong relationship 

 to Ceniropogon of Central and South America, Lobelia proper, to species occur- 

 ring in equatorial Africa as the highlands of Abyssinia, ]\It. Kenya, and Kili- 

 manjaro, as well as to species found in the islands south of Japan, as Liu Kin 

 and the Bonine Islands: Trematololxlia to a species of Lobelia from the sub- 

 tropical Himalayas, and finally nrigJuiinia to Isotoma of Australia and Aprfaliia 

 of Raiatea. 



Cluppy in his valuable work "r)l)servations of a Naturalist in the Pacific" 

 claims an age of Compositae an age of LobeUoideae as well as an age of Coniferae 

 in the Pacific. He tries to explain the absence of LobeUoideae from the islands 

 of the western Pacific, by stating that during the age of the LobeUoideae, that 

 is to say during the age of their distribution, the western Pacific islands were 

 submerged and that after their emergence from the ocean, the agent responsible 

 for the distriliution of the Leihelioideae had become extinct. It is more probable 

 tliat there were other islands lietween Hawaii and the American continent which 

 facilitated plant migration, while the western Pacific Islands were more or less 

 isolated from the area ivhenee the distribution of LobeUoideae took place. The 

 mountains of the western Pacific islands do not reach such altitudes as in 

 Hawaii, and besides their location in more tropical latitudes would perhaps 

 account for the absence of true Lobelias, which seem to be more favorable to 

 cooler latitudes and altitudes. However the floras of the islands of the south 

 Pacific are far too little known to permit anything but theorizing. While the 

 facts and theories set forth in the previous chapters are not conclusive by any 

 means we must regard them as based on such evidence as is at hand today. 

 More intensive explorations in the islands of the south Pacific may reveal to us 

 the presence of LobeUoideae which would throw new light on the question of 

 their origin and distribution. Suffice it to say that it is doubtful that they 

 will be found in such large numliers as to constitute as striking a feature in 

 the floras as t\\ev are in Hawaii. 



