2 3 'i 



those ol' llie other Howers, and in »S. cerniui llie leriniiial 

 flower is often the only one whicli is developed. 



Irrepniar flowers occnr in S. ceniua^ S. oppositifolia and 

 iS. rivularis. 



V. Pollination. The ilowers have colour, and lioney 

 is secreted hy the base of tlie pistil; in some instances scent 

 lias been noted. Insect- visitors have been observed in several 

 of the species in Spitzbergen and Nova Zembla, especially by 

 Kkstam, and in the mountain regions of Northern Europe by 

 LiNDMAN, SiLÉN, Skottsberg aud Sylvén. 



Pro tan dry is so common in the genus Saxifragu that 

 Engler (Bot. Zeitung, 1868, and in his ".Monographie der Gattung 

 Saxifraga"! even gives it as a generic character; that is also one 

 of the reasons why he refers S. crassifolia and other proto- 

 gynous species to the genus Bergenia. The nine species of 

 Saxifraga mentioned by H. Müller in "Alpenblumen" are also 

 nearly all decidedly protandrous, some protogynous species 

 are however mentioned {S. muscoides, S. androsacea, S. Sequieri), 

 and one, viz. S. oppositifolia, oscillates between slight protogyny, 

 slight protandry, and homogamy. To these Müller afterwards 

 added S. tridactylites as protogynous, while Sprengel found it 

 to be protandrous. 



The above-mentioned Arctic species give further proof that 

 protandry is not a generic character; true, it occurs most 

 commonly, but, firstly, it appears usually to be somewhat 

 slighter — at least than it is in many cultivated species which 

 I have observed in the Hortus Hafniensis, almost all of which were 

 decidedly protandrous; usually, they become very soon homo- 

 gamous : I have observed protandry in >S'. aizoides, Aizoon, cer- 

 nua, groenlandica, hieraciifolia, Hirculus, nivalis, rividaris, 

 stellaris and tricuspidata, as also in Crysosplenium. Secondly, 

 the same species often varies, being either protandrous-homo- 

 gamous, or homogamous from the first. S. groenlandica, hie- 

 raciifolia, nivalis, rivularis, stellaris, tricuspidata and Chryso- 



