216 Fr. J. Mathiesen. 



between the stigma papillae and pollen granules of the short- 

 and long-styled flowers. Pr. egaliksensis and Pr. farin. v. 

 groenlandica have homomorphic flowers, the stigma being level 

 with or slightly below the middle of the anthers. The 

 flowers of Pr. stricta may perhaps generally be regarded as 

 homomorphic, with the stigma placed a little above the 

 anthers, but flowers are also found with the stigma raised 

 considerably above the anthers, while others, have it situ- 

 ated much lower than the base of the anthers. Although 

 I found a considerable number of flowers of Pr. nivalis with 

 a very short style, the corresponding long-styled form seemed 

 entirely lacking, and the greater part of the flowers examined 

 had the stigma placed a trifle below the base of the anthers. 



All species must be considered entomophilous ; the 

 Androsaces species are visited especially by Diptera (H. 

 Müllek). 



Failing visits by insects, self fertilisation can probably 

 take place without difficulty in the Androsaces species, Pr. 

 egaliksensis, Pr. farin. v. groenl. and also in those flowers of 

 Pr. nivalis, where the stigma is about level with the anthers. 



C. Anatomy. I. According to their anatomical struc- 

 ture, the roots of the species examined can be classed 

 into two groups, the first representing the mesomorphic, the 

 second the more xeromorphic type (see Decrock). 



1. The root of all the Primula species has a thin-walled 

 and short-lived epidermis. Its protective function is as- 

 sumed by the outermost layer of the primary cortex, the 

 elements of which fit closely together, forming an exodermis, 

 with the outer walls often slightly cutinised. The primary 

 cortex is relatively an extensive tissue and, in Pr. sibirica 

 and Pr. nivalis, its cells have somewhat thickened walls. An 

 endodermis with Gasparian spots can always be distinctly 

 observed. The number of hadromal ravs in the central 



