Wall. — Ranunculus paucifolius T. Kirk. 99 



and the analogy of other lands would seem to show that such a climate 

 may have existed in New Zealand independently of any glacial epoch, 

 whether that epoch be (with Hutton) older Pliocene or (with Speight and 

 others) Pleistocene. The question whether the " drought " be Pliocene or 

 Pleistocene is here dwelt upon because, whatever conditions obtained and 

 whatever balance was established at the end of the " drought," if that 

 ''drought" were Pliocene that balance must in all probability have been 

 disturbed and a new set of conditions reached when the later Pleistocene 

 glacial period came. The problem is, then, to discover what were the con- 

 ditions during and after some more recent period, rather than during and 

 after the exceedingly remote period of any possible Pliocene glaciation and 

 concomitant steppe climate. 



(2.) Glaciation also has been supposed to have been the chief, though 

 not the sole, eroding agency by which the great area of Tertiary beds was 

 destroyed (Hutton, 1885, p. 92 ; Speight, 1915, p. 337). The question 

 of the agency by which, and the probable period during which, these beds 

 have been destroyed is, however, one of secondary import in this connection. 

 It is enough, for the botanical problem, if it is decided that they once 

 existed, have been in one way or another largely destroyed (being now repre- 

 sented by the small isolated fragmentary areas which remain to us), and 

 that the Trelissick Basin (including the small area here studied) escaped 

 glaciation and any great degree of refrigeration during any glacial epoch. 

 We may then imagine the ancient birthplace and hajjitat of Ranunculus 

 'paucifolius and its associates to have been a semi-desert area of flat or 

 flattish plains diversified with ridges and islets of higher ground, and neigh- 

 boured closely by a range of limestone hiUs or even mountains. The whole 

 landscape would have a yellow hue ; upon the surface large areas of unstable 

 shifting debris would possibly alternate with ridges of more grassy and 

 closed formation. Strong winds would be frequent and dust-storms violent. 

 The vegetation would be sparse and harsh, including the species here 

 described, and no doubt many others which have perished ; a pale-purple, 

 greyish, and brown colour scheme would predominate. The land would 

 be occupied by no animals save lizards and birds, its whole appearance 

 being monotonous, parched, and glaring ; while the dreariness of the 

 scene would be enhanced by the setting of pallid limestone rocks pf 

 gTotesque and fantastic form — chessmen, collar-studs, sea-lions, and gorilla 

 torsos. The general appearance of the limestone desert might be much 

 like parts of the Sahara — e.g., as figured in plate 345 of Schimper's Plant- 

 geogra'pJiy , p. 614. 



If Speight's (1911) hypol^esis of a pluvial climate in post-glacial times 

 be accepted — and certainly the evidence collected by him seems to be 

 conclusive — this community and others Like it must have passed through 

 and survived such a period, unless the districts in which they exist have 

 been specially favoured. There is little or no reason to suppose that this 

 was so, for; although Cockayne (1900) mentions that the Trelissick Basin 

 is now very dry climatically, old residents do not support this view ; and, 

 in any case, the fact, if established, that it is now dry does not prove that 

 it was always so in the remote past. 



Origin of the Group to which it belonged. 



With regard to the historical development of this group of Ranunculi, 

 if the neo-Lamarckian view of the origin of species be adopted — the theory 



