559 



groups M* and N- each show 3 per cent, above the normal. 

 This indicates that the environmental factor favours low trees 

 or shrubs. The most marked departure from, the normal is 

 in the therophytes. Annuals are a very prominent feature 

 in the Ooldea florula as far as it is known at present, while 

 it is probable that collections made in a "good season" would 

 still further enlarge the class. 



These deviations from the normal become the more inter- 

 esting when considered in relation to the biologic spectra of 

 other arid regions. Closest correspondence is seen between 

 that of Ooldea and the Death Valley, California. The thero- 

 phyte percentage of 34 is sufficient to mark the Ooldea region 

 as belonging to the desert series, but the number of low 

 woody plants is exceptional. The micro- and nanophanaero- 

 phytes together (M. and N.) amount to 43 per cent., a 

 number in excess of both the normal spectrum or that of any 

 other arid region available for comparison. Further work on 

 the Australian flora is needed before the significance of this 

 can be fully appreciated. While the Ooldea region may be 

 said to show a therophyte flora, the tendency of its peren- 

 nials to be woody plants and to have their resting buds above 

 the surface of the ground and not below it (Class H. is re- 

 markably subnormal) is certainly a point that calls for further 

 investigation . 



Department of Bot.any, University of Adelaide. 



Appendix. 



The following list contains the complete flora of Ooldea so 

 far as recorded at present. We have distinguished the species 

 recorded by Black and not seen by us by prefixing the letter B., 

 and two species of Acacia are given on Cannon's aiithority. The 

 six divisions showing the habitat are shown by the following con- 

 tractions: — Nnllarbor Plain, N.P. ; Dongas, D. ; Sand ridges, 

 S.R. ,- Sand flats, S.F. ; Soak, S. ; and Salt Lake, S.L. 







4) 



















«J 



p^ 





es 



&r 





i4 









5zi 



ft 



od 



od 



OQ 



ai 





Callitris verrucosa, R. Br 



M. 







+ 1 









Triglochin centrooarpa, Hook 



Th. 







+ 







B. 



Panicum gracile, R. Br ... 



H. 













B. 



Amphipogon strictus, R. Br., v. gracilis 



H. 







+ + 









Stipa setacea, R. Br 



H. 



+ 



+ 





+ 



-f 





S. scabra, Lindl 



H. 



+ 



+ 









B. 



S. sclerata, Behr 



H. 









+ 









Danthonia penicillata, F. v. M 



H. 



+ 





+ 









Triodia irritans, R. Br 



Ch. 







+ 









