Scrophulariaceae. 



469 



stem has reached its full development (i. e. at the end of 

 the flowering period), there is found in the stele a continuous, 

 but narrow ring of vessels and a few layers of wood-fibres, 

 strengthened internally by the outermost layers of the pith, 



Fig. 39. Pedicularis hirsuta. 

 A, Transverse section of the leaf. B, A non-glandular hair from the 

 basal portion of a leaf. C, Epidermis of the upper, and D of the lower 

 surface of the leaf. (Greenland.) {A about iio/i; B about '"/i; C and 



D about 220/^.) 



the cell-walls of which become somewhat thickened and ligni- 

 fied; the central part of the pith dies away. In the basal 

 part of the stem which bears the leaf-rosettes (the mesocorme), 

 a transverse section shows a circle of vascular bundles with 



