HORN EXPKDITION — BOTANY. 123 



Hvdroiofvle frac-hyiarpa, Jst>.'ii/!i(i petnca, Cynoi::;lossn)ii DritininoJuii, Cullitris, 

 C/ici/aiit/ies tcittiifolia, C. vci/ca, and Granunitis ruficfolia. 



Thu majority of the Larapiiitiiie species was ovigitially discoveiecl within the 

 region, hut in hiter years tliis saxatile Hora has hecMi known to extend ttj Mount 

 Oiga, the Musgrave, and Everard Ranges in tSouth Australia, and to cross to tiic 

 Cavcnagli Range in West AnstraHa. Tlnvse elevations must therefore he regarded 

 as botanical outliers of the Larapintine region ; furthermore, the range of others 

 lias lieen exteniUul north and north-west, far beyond the limits of this remaikablc 

 physiographic area Thus it has come tu pass that a few species only remain as 

 yet restricted to within its boundaries. 



3. Oki(;in of thk Floha. 



In my sketch " On the Tnlluence of Physiographic Changes in the Distriliu 

 tiou of Life in Australia" (Austral. Assoc. Adv. ticii'nce, vol. i., pp. 312-32-'), 

 188'J), I have indicated that the llora of Australia consists of the following 

 constituent elements : — 



1. An immigrant portion derived from at least two separate sources, [a) 

 Oriental and {/>) Andean. 



2. An endemic or Australian i)ortion, which is relatively of higher antiquity. 



((?). That the Autochtlmnian constituent, which occupies the siiuth-west 

 corner of West Australia, was dismembered in Cretaceous times. 



{I'). That the Euronotian constituent was sujjerimposed by the Oriental 

 and Andean incursions. The Andean immigration was proljably 

 coeval with the last glaciation of Australia, which may have lieen 

 in late Cretaceous or in Paleocene tinjes, and if so then a[)proxi- 

 mately cotemporaneous with the dismemberment of the piiniiti\e 

 Australian thira, and therefore antedated the (Jriental innnigration, 

 which has \irtually n<it ceased since its aihent. 



(c). That in Post-Pliocene times there originated in Central ^Vustralia an 

 Eremian flora developed from Autochthonian and Euronotian 

 elements, and largely modilied l)y Oriental immigrants and the 

 species evolve<l from them. 



In the essay aljove referred to I have dealt with the bijtanical characteristics 

 of the Eremiaii region, and they need not be icpeatrd heic, as the main facts 



