121 



veloped epidermis. The secondary cortex is found, early in June 

 and consists of regularly arranged cork-cells (Segerstedt). The 

 limit between the yearly rings of growth in the wood is not 

 sharply defined, neither is there any difference between the 

 spring and summer (or autumn) wood. 



The roots have not been investigated (cf. Hesselman). 



Yaccinium Vitis-idæa L. (forma pumila Hornemann). 

 (Figs. 32—33.) 



Segerstedt,- p. 26. 0. G. Petersen, p. 81. Tedin, 1892, p. 74. 

 Macry, 1887, p. 108. Hesselman 1900, p. 27. 



1 have had specimens for investigation from the following 

 localities: — West Greenland: Isortok (June 8, Kornerup); Kri- 

 stianshaab (July 26, 1884, Hartz 1890). Norway: Bosekop (July 9, 

 1885, E. W.); Kåfjord (July 10 and 16, E.W.); Tromsö (July 13, 

 1884, E.W.); (Dovre) Kongsvold (July 13, 1887, E. W.). 



The leaf has no special protective hairs. 



The upper and 

 lower epidermis have 

 much-thickened outer 

 walls, with cuticle and 

 beneath that a cuti- 

 cularized layer, and 

 slightly undulating, 

 thickened lateral walls 

 with numerous pores. 

 Chlorophyll grains oc- 

 cur in the lower epi- 

 dermis. In small hol- 

 lows on the lower 

 surface multicellular 



Fig. 32. Vaceinium Vifis-idœa. 

 The leaf. Cf. note p. 81. (Greenland.) (H.E.P.) 



(glandular) hairs occur which are, however, of no importance 

 as protective devices. The stomata are confined to the lower 

 surface and do not project. The outermost layer of the inner 



