Scrophulariaceae. 



427 



Habitat: In Greenland it grows in mossy bogs, and 

 in damp piaces 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 

 \villow copses, herb-slopes and heaths. On Nova Zembla Ek- 

 STAM found it growing in dry localities, which were exposed 

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

 in Lille 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 striicture is 

 shown in the transverse 

 sectionfiguredinFig. 22. 

 The secondary grow^h 

 is not considerable, and 

 does not greatly exceed 



what is shown in the figiire 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 adventitious 



root (about ""'i). 



