. Plants of New Zealand. It is obviousthat these plants may be divided into two groups, (1) thosethat are very closely related to mainland forms, (2) those thatare not closely related to any species of the the latter are some of the most magnificent plantsof the Flora (, Pleurophyllum speciosum ; Myosotidium.) Now, there are two possible explanations of the distributionof species limited to narrow areas and solitary islets : (1) itmay be due to 7-elict e7idemis7n, that is to say, the plant wasonce widely distributed, but has for some reason or otherbecome almost extinct, a
. Plants of New Zealand. It is obviousthat these plants may be divided into two groups, (1) thosethat are very closely related to mainland forms, (2) those thatare not closely related to any species of the the latter are some of the most magnificent plantsof the Flora (, Pleurophyllum speciosum ; Myosotidium.) Now, there are two possible explanations of the distributionof species limited to narrow areas and solitary islets : (1) itmay be due to 7-elict e7idemis7n, that is to say, the plant wasonce widely distributed, but has for some reason or otherbecome almost extinct, and now exists only on outlyingislands, or in remote corners of the mainland. Thus, to takean example from the human race, the limitation of the oncewidely distributed Kelts to Brittany, Wales, Ireland, and theNorth Scotland, is a case of relict endemism. (2) If, however,the species has been developed on the off islands, or outlyingpeninsulas, owing to special conditions existing there, then we THE FAMILY OF ARALIADS 303. Pig. 97. Nothopanax Colensoi (.^ nat. size). 304 PLANTS OF NEW ZEALAND have a case of initial endemism. Now it is often difficult tosay which explanation should be adopted, in a given the plant is closely allied to one existing on the mainland,we probably have a case of initial endemism. If, however,it belongs to a type not represented on the mainland, it ismore likely that we have to do with an example of relictendemism ; and that the species was once widely distributed,and now, having been almost exterminated, finds a sanctuaryonly in inaccessible localities and remote islands. In somecases Palaeo-botany comes in to give us assistance in solvingthe problem. Thus, fossils show us that the genus Agathiswas once widely distributed, though now restricted toAuckland province (where the Kauri is found), to the MalayArchipelago, and to Queensland. Thus in the Kauri we havea clear case of relict endemism. The older botanists,however, generally neglected this
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