107 



sists more or less of elongated, irregular, parenchymatous cells 

 which are branchless. The vascular bundle in the middle of the 

 leaf is accompanied by a sclerenchymatous bundle which is 

 large compared with the size of the leaf. The walls of the meso- 

 phyll are coloured slightly yellow by chlor-zinc-iodine. 



The primary cortex of the stem consists of transparent 

 cells without contents with a few which are thicker walled, and 

 of trabeculæ like those in Andromeda and Ledum. It persists 

 for several years. The secondary cortex consists of irregularly- 

 angular corky cells. The annual rings are not distinct. 



I have not examined the root (cf. Hesselman). 



Andromeda polifolia L. (Figs. 23—24.) 



BöRGESEN, 1895, pp. 234 — 235. Segerstedt, 1894, pp. 29—34. 

 O.G.Petersen, 1901, p. 77. Schulz, 1888, pp. 254 — 255. 



The specimens 1 have had for investigation are from the 

 following localities: — West Greenland: Tiningnertok (62° 20', 

 June 6); (Finmark) Bosekop (1885, E. W.) ; Tromsö (June 28, 

 1884, E. W.). [Denmark: bog at Herning (Aug. 5, 1887, E. W.); 

 bog at Farum (Febr. 24, 1907, H. E. P.)] 



The leaf. The outer walls of the epidermis are much 

 thickened (6 — 8 ju in the specimens from Tiningnertok) by the 

 presence of a thick cuticle and beneath it a cuticularized 

 layer. 



The upper epidermis has much-undulating lateral walls, 

 and inner walls containing ligneous substances which are coloured 

 red by phloroglucin-muriatic acid, a fact which is peculiar to 

 Andromeda and does not occur in the other forms treated of 

 in this paper. Hairs occur on the lower surface of the leaves 

 in the Greenland specimens, but not on those in the Danish 

 or Norwegian ones (Borgesen, 1. с); the above-mentioned 

 hairs do not play any prominent part as protective structures, 

 the layer of wax on the lower surface of the leaf which occurs 



