40 B Canadian Arctic Expedition, 1913-18 



nature of environment several very distinct types of habit may be observed at 

 the same station, whether in the far north or in the alpine regions of the moun- 

 tains. Thus among the plants which are growing nearest the Pole, between 

 82° and 83° 24' N., gathered by the British polar expedition, 1875-76, and the 

 late Lieut. Lockwood, United States Army, we find not less than six species of 

 Saxifraga, viz.: S. cernua, S. nivalis, S. decipiens, S. tricuspidata, S. fiagellaris, 

 and S. oppositijolia. And according to Hooker ^ S. cernua and S. fiagellaris 

 ascend to an elevation of above 17,000 feet in the Himalayas; furthermore, in 

 the Rocky mountains, Colorado, I collected S. cernua, S. fiagellaris, and S. 

 nivalis above 14,000 feet alt. In other words, the sections which are able to 

 thrive at the stations farthest north are Nephrophyllum, Boraphila, Dacty- 

 loides, Trachyphyllum, and Porphyrion ; three of these : Nephrophyllum, 

 Boraphila, and Trachyphyllum, are among those that ascend to the highest 

 latitudes. 



As pointed out by Engler (I.e. p. 57), the majority of the species are moun- 

 tain plants and many of these belong to the alpine flora. This author gives an 

 interesting table according to which the largest number of species occur in the 

 European Alps from France to Croatia (42 sp.); then follow Tibet and the 

 Himalayas with 35 species, the Pyrenees with 30, the Carpathian mountains 

 with 25, the Rocky mountains with 22, etc. Only 5 species are credited to the 

 South American Cordilleras. 



The majority of the species are herbaceous but very few are annual, and 

 several may be designated as undershrubs. Among the perennial herbaceous 

 ones some interesting structures are to be observed with respect to the vegetative 

 reproduction, the development of runners above the ground, and of bulblets' 

 developed in the axils of the leaves, the basal as well as the cauline, in the latter 

 case representing transformed flowers as in S. cernua and iS. stellaris forma 

 comosa, for instance. But although the primary root persists in many species, 

 no instance is known, so far, where the root increases in thickness to any great 

 extent, as is otherwise a feature characteristic of various mountain plants, 

 especially the alpine ones. 



The arctic species collected by the expedition constitute actually an 

 assemblage of types in which the vegetative reproduction gives an excellent 

 illustration of the biology of the genus in the arctic and alpine regions. 



Saxifraga aestivalis Fisch. et Mey. 



The plant upon which Linnaeus established the species came from Siberia, 

 and according to Ledebour the species occurs also in Alaska and arctic America. 

 However, some Siberian specimens which I have before me, collected near 

 Jakutsk (N. H. Nilsson), and at Tolstoi Nos (M. Brenner) differ from the Alaskan 

 as well as from the arctic American by the leaves (Fig. L : 3) being of a more round- 

 ish outline and of a thinner texture, besides by the flowers being considerably 

 smaller. The structure of the rhizome, however, is identical (Fig. 1) ; it is ascend- 

 ing or sometimes vertical, quite thick, and bears numerous leaf-scars from 

 green leaves while scale-like ones are entirely absent. Slender secondary roots 

 are developed beneath the leaves, and the primary root evidently dies off at an 

 early stage. The leaves form an open rosette and the flower-bearing stem (St. 

 in fig. 1) terminates the shoot; an axillary bud remains dormant through the 

 winter and produces a rosette of leaves and an inflorescence during the next 

 spring. Lateral branches develop often from the rhizome, especially when 

 growing in Sphagnum bogs. While thus the Siberian plant differs somewhat 



' Introductory Essay to the Flora Indica. London, 1855, p. 221. 



