38 THE VOYAGE OF H.M.S. CHALLENGER 



in the forms of their flowers, such as Bagnisia (New Guinea), Geomitra (Borneo and Java), 

 Corsia (New Guinea), and Arachnites (Chili), are apparently local or very local. In con- 

 clusion, one or two examples of genera represented by the same species in widely separated 

 areas may be given : Diphylleia, a genus of Berberidacese, regarded by Dr A. Gray and 

 other botanists as monotypic, inhabits Japan and Virginia and North Carolina. The 

 eastern Asiatic plant has, however, been described as an independent species. Coleanthus, 

 a genus of grasses, is another monotype inhabiting widely separated areas, having been 

 found in France, Bohemia, and Norway, and also recently in Sauvies Island, in the mouth 

 of the Oregon river, North-west America.' In this instance there is no question of the 

 identity of the species. 



DISTINCT CONTINENTAL SPECIES OF VERY RESTRICTED AREAS. 



From what has been said in the paragraphs on orders and genera of very restricted 

 areas, it follows that the number of continental species found in single localities or districts 

 is large, amounting perhaps to thousands. Therefore it will be sufficient to name a few 

 well-authenticated instances of such plants in order to demonstrate that very local species 

 are not peculiar to oceanic islands, and that some plants are unable from some cause or 

 causes to extend their areas, though able to hold their ground in certain localities. 



Hudsonia niontana, Nutt. ; Chapman, Fl. Southern U.S., p. 36. — A very small- 

 flowered, very small shrubby member of the Cistinese, found only on Table Rock, North 

 Carolina. The genus comprises three species restricted to the eastern maritime states of 

 North America. 



Neviusa cdabamensis, A. Gr. in Mem. Amer. Acad. Sci., N.S. vi. p. 374 ; Bot. Mag., 

 t. 6806. — A member of the Rosacea?, hitherto only found near Tuscaloosa, in Alabama. It 

 is the only species of the genus, and might, therefore, also figure as an example of a 

 continental genus of very restricted area. 



Saxifraga floridenta, Moretti, Tent. Saxif., p. 9 ; Bot. Mag., t. 6102; Regel, Garten- 

 flora, 1874, pp. 2 et 314, t. 782. — This very distinct and striking species is very local, yet 

 not uncommon within its limited area. Sir J. D. Hooker (Bot. Mag., loc. cit.) states 

 that it was first discovered in the Alps of Fenestre, about the year 1820, by an English 

 tourist ; and he says it appears to be tolerably abundant at an altitude of from 7000 to 

 9000 feet within an area of about eight square miles, in the Maritime Alps, between the 

 Col di Tenda and the valley of the Tinea, north of Nice, but is not found elsewhere. 



Dioncea muscipula, Ellis; Chapman, Fl. Southern U.S., p. 37 ; Bot. Mag., t. 785. — 

 This and the next are given as examples of genera of restricted area. North and 

 South Carolina. 



Rhodoleia championi, Hook., Bot. Mag., t. 4509. — In the paragraph on genera of 

 very restricted areas, special mention is made of the local character of several of the 



