132 HORN EXPEDITION — BOTANY. 



first series, when viewed by their present geographic distribution, are considered 

 Oriental; but in regard to their distribution, in time they belong to a Cosmopolitan 

 flora, which originated in Late Cretaceous times in Europe, North America, and 

 Australia ; hence their modern representatives, except the exotic species, may 

 actually be descendants of primitive Australian species, and not modified immi- 

 grant forms. 



The isolation of many of the Larapintine species and the sporadic occurrences 

 of others are facts suggestive of the opinion that they are modified descendants of 

 a j^rimitive flora. Thus the fan-palm, Livistona Mariic, is known by one colony 

 only, estimated to comprise not more than a hundred mature individuals, and 

 though seedlings are numerous, yet very few juvenescent exumples were observed ; 

 also on the banks of the Finke River, below its junction with Palm Creek, con- 

 siderable numbers of young plants were seen, whilst the number of full-grown 

 trees does not exceed a dozen. It may therefore be inferred from these circum- 

 stances that a powerful agency is at work repressing the increase of individuals 

 and endangering the very existence of the species. The grass-tree, Xantliorrlura 

 Thorntoni, is restricted to a belt of sandy country of about seventy miles long and, 

 thirty miles wide. Brachysema Chainbersii is gregarious, though usually the 

 colonies are extensive. Xerotes dura is known in two colonies of a very limited 

 number of individuals, some flfty miles apart. Sivainsonia canescens occurs in two 

 colonies, occupying a few scjuare yards, seventy-seven miles apart. Gaslrolobium 

 grandifiorii ni is very local and the colonies widely separated. Goodeiiia Honiiaiia 

 occurs in two colonies of few individuals, separated by 100 miles. Bccckea poly- 

 stemonea is restricted to two localities, 260 miles apart. Whilst Adinotus 

 Schivartsii, Didiscus Gillencc, Prostanthera Schu/lzii, Styphelia Alitchelli and a few 

 others are restricted, so far as known, each to a circumscribed habitat. Moreover, 

 some of the endemic species of exotic genera, and even some immigrant species, 

 occur in small single colonies. Of the former may be mentioned Grainntitis 

 Reynoldsi and Ottelia ovali/olia, and of the latter Hcleocharis capitata, Lipocarplui 

 microcepha/a, Psilotum iriijueiruiii, Adiantiiin hispidiilu/n, and Aspidium milium. 

 As the majority of these exemplar species are so conspicuous, or of others because of 

 the particularity of their habits, there cannot be room to doubt the general appli- 

 cability of the opinion which I have formed as to their sparse distribution. And 

 though a suspicion may be raised that they are stragglers from outlying regions, 

 yet our knowledge of their extra-limital distribution forbids such an explanation. 

 Thus for the majority of the species the Larapintine region is their metropolis, 

 whilst others which range beyond it are equally sporadic in their occurrences. i.i\ 

 the latter category the following selected species may S('r\e as illustrations : — 



