410 



Tlie erect peduncle atlaiiis a lieiglil of from 5 to 20 cm. 

 and bears a tripartite involucre wiiicli, wlieii llowcriiit,' begins, 

 is seated above tbe middle oi' Ibe peduncle, but is considerably 

 below tbat point wlien tbe fruits are ripe, tbe upper part of 

 the axis having elongated greatly. The peduncle is somewhat 

 hairy, the hairs being most dense upon the upper part. 



The flower has 3 -{- 3 yellow perianth-leaves, sometimes 

 4 + 4, and the leaves in the whorl are of unequal size (Fig. 

 51, C). In the expanded flower the fdaments are bent out- 

 wards towards the perianth-leaves, the anthers are introrse. 

 At lirst the long backwardly-turned styles are erect, but after- 

 wards, they probably become so far turned outwards that they 

 can reach the anthers. The diameter of the flower is 19 — 

 22 mm. Honey is absent. (Warming, notebook). 



Flowering begins at the end of June and is continued into 

 August. The fruits may certainly be dispersed epi/oically, as 

 the styles of the carpels are long (about 4 mm.) and hooked 

 at the apex (Fig. 51,/>). 



In Greenland it has been found only at Holstensborg and 

 Sukkertoppen; it grows there in damp places in willow copses. 

 It is morever found in arctic and subarctic America from 

 Hudson's Bay to Alaska, Rocky Mountains, Unalaschka, East 

 Siberia (Lange). 



Anatomy. The roots are slender and branching; they 

 remain in the primary condition. In their anatomy they greatly 

 resemble those of A. nemorosa. The epidermis is suberized ; 

 its outer wall is fairly thick, and highly convex. The cortex 

 is 5-layered and compact in structure with very small inter- 

 cellular spaces, the walls of the cells are fairly thick. The 

 starch-grains in the cells are both single and compound. The 

 cells of the endodermis are tangentially elongated, the walls 

 are somewhat thickened and are corky: the pericycle is one- 

 layered. The central cylinder is diarch, in the larger roots the 

 woody parts meet in the middle. In the more slender roots 

 the epidermis is collapsed. 



