20 MORTFN I*-. l'dIlSII.Il. 



Thoy aro almosl willioiit any exceptiiui Idwlaiid plaiils at llic northorn 

 limit of thfir horizonlal distrildilion. 



Our uso of tho exprossioii Iowland is rrlalive, somewhal varying 

 according to llio looality. On tlio iiortli side of hig massives vve denole 

 as lowlaiui a level as Iow as a coiiple of hundred meters ahove sea-level, 

 on the south sidr and in piolected piaces in the interior up to -400 — 500, 

 ocoasionally even up to GOO — 700 meters above sea-level. The decisive 

 proof to us has heen whether the place had old concentrated vegetation 

 or fresh moraine soil witli open vegetation. 



Generally \ve have not stated the exact dates of flowering of 

 the piants. After liaving kept, through a longer period of years, a journal 

 of the earliest flowers from a single place and its vicinity we have arri- 

 ved at the conclusion that a certain succession in thr time of 

 flowering can be proved for a majority of the arctic species, i)ut that 

 the actual dates may vary at least 6 weeks, namely just as much 

 or more than the date varies at which the positive mean temperature 

 begins. A few pronounced arctic species have no definite flowering 

 season al all. they flower continuously throughout the period of vege- 

 tation. 



As a general faet may be stated that the true arctic species (north- 

 ern and widely distributed types) flower early, the subarctic or tem- 

 perate la te, provided that they attain to put forth flowers at all. When 

 two systematically closely allied species belong each to its own type a 

 characteristic difference, as to their flowering season, may be found, 

 tilis faet being supported by numerous examples: 



Early flowering. Lato flowering. 



Jji'schampsia caef;pitosa var. piiniila I). alpina. 

 Liizula confusa, L. niralis. L. jrigida, L. spicata. 



Slrllaria longipcs^ Sf. luunijusa. St. horealis. 

 Pott'fitilla Vahliana, P. iiivea. P. al pestris. 



Chamaenerinm latifolium. Ch. (in^uslifoliiiiH. 



Pirola }iramliflora. P. ii/inor, P. secunda. 



Pedicularis lanala, P. hirsuta. ol her species of P., the latest flow- 



ering is /'. eiip/irasioides. 

 Eriiirrofi eriocephalus. E. unalaschkensis. 



Antennaria alpina. A. intermedia. 



etc. 



At anolher occasion we hope to come back to this subjecl, mean- 

 while conlining our attention here to statements of early and late 

 flowering in such cases where this seemed especially characteristic 

 to us, just as we everywhere have stated absence of flowering as far 

 as this was known to us. 



