Arctic Plants: Morphology and Synonymy 43 b 



In the section Nephrophyllum we meet with several species which develop 

 bulblets upon the rhizome as well as in the inflorescence; this peculiarity was 

 known already to Linnaeus when he described S. granulata "radice granulata." 

 Afterwards the morphology of this plant has been described so very excellently 

 by Irmisch (I.e. p. 190). 



Among the arctic representatives of this section, S. cernua L. is the most 

 frequent one. The rhizome is very short and the primary root must be of a 

 very short duration since it constantly lacks in mature specimens. In this 

 species bulblets (Figs. 4-5) are developed not only in the axils of the basal, green 

 leaves but also in the inflorescence where they sometimes replace all the flowers.* 

 Most frequently the bracts of the inflorescence subtend only single bulblets, 

 corresponding to single flowers, but in some remarkable specimens gathered by 

 James M. Macoun at Fullerton, Hudson bay, the bracts subtend numerous 

 clusters of bulblets; in these vigorous specimens the inflorescence was profusely 

 decompound instead of being a simple raceme as in the typical plant. On the 

 other hand, in S. debilis Engelm., which Engler considers to be merely a variety 

 of S. eernua (I.e. p. 107), these bulblets are totally absent. 



The bulblets of the inflorescence are of a pink colour and they germinate 

 freely when separated from the mother-plant. According to Warming,^ slender 

 stolons may also occur in this species, and the foliage of such stolons may consist 

 of scale-like as weU as of green leaves some of which may subtend bidblets. 



S. radiata Small.^ 



This is S. exilis Stephan (1822) but the latter name has been rejected since 

 there is a S. exilis Poll, of earlier date (1816). The species S. radiata, (Fig. M: 

 6-7) resembles S. sibirica L. very much, but in S. radiata the stem is pubescent 

 with glandular hairs intermixed; the basal leaves are merely 5-7-lobed, and the 

 petals are very distinctly three-nerved. Bulblets occur in both species, mainly 

 in the axils of the basal leaves, seldom in the inflorescence. 



S. rivularis L. 



This little species forms small cushions, but the primary root is substituted 

 by a dense mass of filiform, secondary roots; the rhizome is very short and bfears 

 rosettes of leaves with terminal flowering stems. When growing in loose, wet 

 soil, or in moss, the rhizome may develop horizontal stolons (specimens from 

 Camden bay), which bear typical green leaves. Bulblets occur also in this 

 species as described and figured by Warming (I.e. p. 211), and by G. Lindmark.* 



The section Hirculus comprises mostly Himalayan species, but one of 

 these, S. Hirculus L., is also widely distributed throughout the northern hemis- 

 phere and reaches the polar regions in both Worlds. The arctic plant is low, 

 che flowering stems reaching a height of only 6 cm. or less; it forms small and 

 more or less compact cushions of numerous leaves, and several flower-bearing 

 stems are produced on the same individual. There is no primary root in mature 

 specimens but the profusely branched, subterranean shoots bear many filiform, 

 secondary roots. The subterranean stem represents in these arctic specimens 

 from Bernard harbour, Herschel island, etc., a horizontally creeping rhizome, 

 about 7 cm. in length, slender, but woody, densely covered with remnants of 

 withered leaves and branching freely; stolons with scale-like leaves are known 

 to occur in the southern plant but I observed none in the numerous arctic speci- 

 mens, which were examined. Vegetative reproduction is scantily represented by 

 the arctic plant, since the branches of the rhizome are of a solid, woody structure, 

 not permitting the secondary rosettes to become separated from the mother-plant. 



' Compare: the author in Dijmphna-Expeditionen's Zoologisk-botan. XJdbytte (I.e.). 

 2 Saxifragaoeae (Medd. om Gr^nland. K^benhavn, 1912). 

 ' North American Flora, Vol. 22, 1905. 



* Bidrag till kannedomen om de Svenska Saxifraga-Artera yttre byggnad aoh individbildning. Bib . 

 K. Sv. Vet. Akad. Hdlgr. Vol. 28. Stockholm, 1902. 



