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- 
phyl! 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 trabecule 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. Hessermay). 
Andromeda polifolia L. (Pigs. 23— 24.) 
Borcesen, 1895, pp. 234—235. SEGERSTEDT, 1894, pp. 29—34. 
O. G. Petersen, 1901, p.77. Scaurz, 1888, pp. 254—-255. 
The specimens | 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 » 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 (BôrGesex, |. c.); 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 
