234 



Eue. Warming. 



To this type belong the following Sileneæ:-- Melan- 

 drium affine, M. apetalum, M. triflorum, Viscaria alpina and 

 Dianthus superbus. Of non-Arctic: Melandrium diurnum, 

 Lychnis flos cuculi, Silène otites, etc. 



These are all perennial, visually vigorous herbs with a 

 tap-rootwhich remains during the whole life of the plant; but 



they are either devoid of or 

 rarely provided with adventi- 

 tious roots, which, when pre- 

 sent, are insignificant. Vegeta- 

 tive propagation does not 

 take place. 



The larger the individ- 

 uals are, the stronger is 

 the tap-root, and the deeper 

 does it grow down into the 

 ground. 



The shoots are semi- 

 rosette-shoots, i. e. they have 

 a typical rosette at their 

 base, but otherwise have 

 elongated internodes (long- 

 (Spitzbergen). g, Buds on the naked shoots). The leaves are large 



when compared with those 

 of the Alsineæ. Scale-leaves 

 are absent. Lateral shoots, 

 similar in structure to the 

 main shoot, are developed 

 from the axils of the rosette-leaves. All these shoots are 

 erect or ascending. They are most frequently di-pleio- 

 cyclic, i. e. they remain 2 — 3 or more years in a vegetative 

 stage, before their internodes elongate and flowers are 

 developed; many undoubtedly remain throughout their 



Fig. 2. Melandrium apetalum 

 ß arcticum. 



axis, either root-shoots or rather 

 buds from the axils of rosette- 

 leaves which have died and dis- 

 appeared, o, Fragments of dead 

 leaves, b — e, fresh leaves. Hairs 

 omitted. (E. W.) 



