132 B' Canadian Arctic Expedition, 1913-18 



They constitute a very natural little family; with the exception of Pyroja 

 grandiflora and the typical P. rotundifolia, they are sylvan types and they often 

 grow associated with each other forming small colonies; reproduction by means 

 of root-shoots is characteristic of several of the species. We have seen from 

 the geographical table (Table 6) how Pyrola minor extends clear across the 

 northern hemisphere, reaching the arctic regions on this continent, including 

 Greenland, in Scandinavia, and in Russia; a similarily wide distribution is 

 exhibited by P. rotundifolia, it being absent only from our arctic coast, Greenland, 

 and Iceland, and by P. se%unda which is absent from the northeastern corner of 

 Asia: Terra Tschuktchorum and Kamtchatka. Then with regard to Moneses, 

 this shows the same distribution as P. secunda but is absent from Caucasus. 

 Finally; P. chlorantha is absent from ten of the eighteen districts enumerated 

 on the table, namely: our north coast, Greenland, Russia, Siberia, and 

 Iceland, but it is represented in Europe from Finmark south to the Alps and 

 the Pyrenees. 



We have thus four species of a remarkably wide distribution in both Worlds. 

 Nevertheless, the Pyrolaceae are best represented on this continent, the home of 

 three species of Chimaphila, besides oi Pyrola elliptica, P. picta, P. chimaphil- 

 oides, and P aphylla, and the foliage of the last three species resembles that of 

 Chimaphila more than that of Pyrola; in Europe there is a somewhat isolated 

 type: P. media. It is interesting to notice that while P. chlorantha is absent 

 from Asia, Maximowicz ^ discovered a near ally of it, P. renifolia, in coniferous 

 woods in the Amur district where, moreover, P secunda, P rotundifolia, Mon- 

 eses, and Chimaphila umbellata were collected. 



It would thus appear as if the centre of the Pyrolaceae might have been 

 located on this continent, rather than in the Old World, inasmuch as the Mono- 

 tropeae, the nearest allied family, are also best represented here, with seven 

 mostly monotypic genera of which Monotropa is the only genus occurring also 

 in Europe. 



However, when we bear in mind that P. minor and typical P. rotundifolia 

 are much more abundant in Europe than on this continent, it might be more 

 orrect not to include them in the American element, I mean the element 

 which presumably originated on this continent. 



With respect to P. chlorantha it seems difi&cult to combine its distribution 

 in Europe with that on this continent and, as stated above, it is absent from all 

 of Asia. The occurrence of Chimaphila umbellata in Europe causes also some 

 difficulty but its distribution in Asia, Altai for instance, may point towards a 

 former, much wider distribution, at present disconnected. 



Taking all points into consideration it seems a most difficult task to treat 

 the distribution of this singular little family, almost exclusively confined to the 

 temperate regions of both Worlds, and being mostly sylvan types. For whether 

 their centre of distribution, or let us say development, be placed on this con- 

 tinent or in Europe, the question will necessarily arise how these little plants 

 have remained so unchanged on both continents when, as stated by Darwin, ^ 

 "by comparing the now living productions of the temperate regions of the New 

 and Old Worlds, we find very few identical species, but we find in every great 

 class many forms, which some naturalists rank as geographical races, and others 

 as distinct species; and a host of closely allied or representative forms which 

 are ranked by all naturalists as specifically distinct." 



With respect to the Pyrolaceae some certain "geographical races" have 

 become developed, notably of Chimaphila umbellata, Pyrola secunda, and P. 

 rotundifolia, but, nevertheless, the typical species are represented in both Worlds. 

 Otherwise with r-espect to the plants with which they are associated. 



1 Prirnitiae Flor. Amur. I.e. p. 190. 



2 Origin of Species, p. 441. 



