124 HORN EXPEDITION— BOTANY. 



relating to the Larapintine flora are eir)braced therein. Nevertheless some aspects 

 of the two types of vegetation locally represented may be considered. 



The Larapintine flora is composed of : — 



I. — Exotic species, chiefly Oriental - - 125 



II. — Endemic .species of exotic genera - - 219 



III. — Endemic species of Australian genera - 270 



614 



In the appended tables, from which the above sunnnary is derived, Pitlosporuiiu 

 Ficus, Ciissia, Saniahitn, and Loranthus are included among the endemic genera for 

 reasons which are explained at page 131, whilst the alliance with South Africa 

 through Helipteruni, ILiiceJ>ha/ar(os, and others, is disregarded as not attecting the 

 main issues touching the origin of the Larapintine flora, and they are also included 

 among the endemic genera. 



The species in categories I. and II. belong, as a whole, to the Eremian type 

 of vegetation, and to these should be added fifty-two in category III., which belong 

 to genera characteristically Eremian though endemic, though it is possible that 

 some of them, particularly the vascular cryptogams and aquatic plants may have 

 formed part of the primitive Australian vegetation. An important factor in the 

 problem of the origin of a flora, here wanting, is the geological evidence of the 

 relative periods of introduction of its alien forms, and it is only our knowledge of 

 the modes of dispersion of plants and the varying rapidity by which unoccupied 

 tracts may be re-peopled that permit us to infer that the vascular cryptogams are 

 the first to appear, then the aquatic and paludinal plants, or on coast-lines some 

 flowering plants by means of water carriage, and lastly the bulk of the terrestial 

 species. 



Table of Exotic Genera, and the Number of Endemic and Exotic Species. 



Genera. 



Endemic 

 Species. 



Exotic 

 Species. 



Genera. 



Endemic 

 Species. 



Exotic 

 Species. 



Cleome 



- 



1 



Elatine 



- 



1 



Capparis - 



- 1 .. 



1 



Bergia 



- 1 



1 



Erysimum 



- 1 . 



. 



Hypericum 



■ 



1 



Capsella - 



- 1 .. 



. 



Polygala - 



- 



1 



Lepidium - 



- 3 



1 



Zygophyllum 



- 6 . 



. 



Hybanthus 



- 



1 



Tribulus - 



2 



1 



Drosera - 



- 



. 2 



Erodium - 



- 1 



. 



