Scrophulariaceae. 



429 



ring, and the almost continuous ring of wood-fibres on the 

 outer side of the latter, and by the outer layers of cells of 

 the pith being thickened and lignified. The central part of 

 the pith has died away, and the stem is consequently hol- 

 low. Stomata occur in the thick-walled epidermis, and chloro- 



Fig. 24. Pedicularis lapponica. 

 A, Transverse section of the leaf. B, Epidermis of the upper, and С 

 of the lower surface of the leaf. (Greenland.) [A about ^^%; В and С 



about 2 20Д.) 



phyll in the cortical cells. In the cases in which the basal 

 portions of the flowering-shoots persist and bear lateral shoots, 

 a second growth-ring — often excentric — may be formed here. 

 The Leaf: As regards the anatomy, there appears to 

 be very little difference between the rosette-leaves and the 

 leaves of the floral shoots. The epidermis of the upper sur- 

 face (Fig. 24, B) has straight to slightly undulating lateral 

 XXXVII. 28 



