HORN EXPEDITION — SUMMARY. 159 



BOTANY. 



The list of plants rocnrdofl liy Pi-ofassor Tato imnihors fil t. Prior to tho 

 Expoditioii tho number doscriliod from the le^'ion w.vs r)02. The additions consist 

 of 8 new species, 10 species new iov South Australia and 11;3 species new to tlic 

 region. 



In his paper* " On the Tnllucnce of Physiooiapliic Chancres in the Disti-il)ution 

 of Life in Australia " Professor Tate suggested, mainly on hotanical grounds, the 

 division of Australia into three regions — (1) Autochtiionian, (2) Euronotian and 

 (.'?) Eremian. The latter region occupies the central area of tiie continent and is 

 coterminous with tiiat over wliich the annual rainfall is under 10 inches ; 

 westward it extends to the coast line f)f mid West Austi-alia. For the cential 

 region occupied by the table-la.nd of Ordovician sandstone from which rise the long 

 parallel i-idges forming th(^ McDonnells and the James Range the name Larapintine 

 is used — adapting the nati\e name of the Finke River the basin of which lies 

 mainly witliin the ai-ca. To tlie south lies what Professor Tate calls the Central 

 Eremian district, stretching south from about tiie latitude of Engoordina (Horse- 

 shoe Bend) on the Finke and formed by the Cretaceous table-land. 



Tiie latter area is practically the same as that referred to in the nari-ative as 

 the Lo7ver Steppes^ the Larapintine region being comprised within the Hii^^Jier 

 Steppes. 



In regard to the Larapintine Flora Professor Tate concludes that after the 

 deposition of the Rolling Downs Formation, which isolated except perhaps in a 

 north(n"n direction the Larapintine table-land (or the Higher Steppes), a lacustrine 

 area was formed during the period of deposition of the Desert Sandstone, and that 

 a cosmopolitan flora prevailed at this period which continued into Paleocene 

 times. Pluvial conditions continued into Pliocene times, whilst in Post Pliocene 

 times a high state of desiccation was reached. Under these changed conditions 

 tlie original " cosmopolitan " flora became largely extinct and an immigi-ation of 

 Oriental forms supervened. The present flora of the Eremian region has been 

 "developed from Autochtiionian and Euronotian elements and largely modified by 

 Oriental immigrants and the .species evolved from them." 



The Larapintine flora is described l)y Professor Tate as follows : — 



I. — Exotic Species, chiefly Oriental ... ... 125 



II. — Endemic species of Exotic geneia ... ... 219 



III. — Endemic species of Australian genera ... 270 



* Aust. As8. Adv. Sci., vol i., pp. :J12-32u, ISSO. 



