INSULAR FLORAS. 455 



Some of these Chlsenaceae, such as Rhodolcena altivola 

 and Sarcolcena grandiflora, have large showy flowers. 



A few of the most peculiar and striking plants of 

 Madagascar are so well known that it is hardly necessary 

 to mention them. For example, Angrcecum se s quip e dale, 

 Ouvirandra fenestralis, and Ravenala madagascariensis. The 

 last is often cited as an instance of American affinity not 

 represented in continental Africa ; and indeed it is the 

 most remarkable and prominent of the endemic plants. 



Among the 150 endemic genera, exclusive of the 

 Chlsenaceae, some stand out so conspicuously from the rest 

 as to demand special notice ; but space will only permit 

 of a few words concerning some of the more curious or 

 prominent. Didierea (26) is an aberrant type, exceptional 

 alike in habit and floral structure, which Baillon refers to 

 the Sapindaceae, though it presents so many points of 

 difference that perhaps it deserves the rank of a natural order 

 equally as much as the Asiatic Dobinea, recently raised to 

 that dignity by the same author. Two species of this 

 singular genus are now known, both from the south- 

 west of the island. The first discovered, Didierea 

 madagascariensis, grows gregariously on the dry plains 

 near Tulear, covering considerable expanses. It has 

 a thick, fleshy stem, simple, or very little branched, 

 recalling the columnar Cacti, but it is not - fluted ; and 

 the small, linear leaves and flowers are in clusters, pro- 

 tected by groups of formidable spines, springing from the 

 same protuberances or cushions. The flowers are uni- 

 sexual, and the floral envelope consists of three decussating 

 pairs of organs, the innermost of which are the smallest. 

 There are eight stamens, and the three-celled ovary with 

 one ovule in each cell matures in a one-seeded triangular 

 fruit, surmounted by a very large three-lobed corrugated 

 stigma. The second species, D. mirabilis, has a stout 

 trunk about twenty inches in diameter, giving off horizontal 

 branches at a few feet from the ground, the whole plant 

 rising to a height of twelve to fifteen feet. 



Among the Leguminosae are several remarkable types, 

 notably Neobaronia of Baker, which, however, had been 



