Scrophulariaceae. 



427 



Habitat: In Greenland it grows in mossy bogs, and 

 in damp places on heaths; the runners creep in the moss, 

 or in slightly decomposed vegetable matter (M. Porsild, in 

 litt.); it is "covered by thick layers of snow during winter" 

 (Porsild, 1920). Warming, 1888, mentions it as inhabiting 

 willow copses, herb-slopes and heaths. On Nova Zembla Ек- 

 STAM found it growing in dry localities, which were exposed 

 to strong insolation. A. Cleve finds it on mountain heights 

 in Lule Lappmark, avoiding wet ground and the poorest 

 heath; she writes: "'Sie 

 gedeiht am besten in 

 den Waldregionen und 

 sucht im Hochgebirge 

 relativ trockene Stand- 

 orte auf, was schon 

 Wahlenberg aufgefallen 

 war." 



Anatomy. The 

 Root: The structure is 

 shown in the transverse 

 section figured in Fig. 22. 

 The secondary growth 

 is not considerable, and 

 does not greatly exceed 

 what is shown in the figure in question. The endodermis 

 is a very beautifully developed Casparian sheath. The epi- 

 dermis dies away quickly; the outer walls of the exodermis 

 were found to be cuticularised. On the surface of the roots, 

 dark-coloured, fungal hyphæ were frequently found. 



The Stem: (1) Runners: The epidermal cells have 

 fairly thick outer walls; they are filled with a homogeneous 

 brown mass, which gave the reaction of tannin. The outer- 

 most cortical layer adjoins the epidermis without inter- 



Fig. 22. Pedicularis lapponica. 



Transverse section of an adventitioiis 



root (about "%). 



