502 Fr. J. Mathiesen. 



investigated, found well-developed in the adventitious roots 

 oi P. sudetica only. 



In the roots of P. Eiiphrasioides, hirsiita and lanata, 

 which had a vigorous growth in thickness, the rather thick 

 secondary cortex was found to be traversed by radiating 

 clefts (Fig. 38, B) ; this was less well-marked in the adventiti- 

 ous roots of P. flammea and Oederi. In P. hirsuta and lanata 

 in which the thin-walled parenchyma — as is also the case 

 in P. flammea and Oederi — is also dominant in the xylem, 

 the clefts are often continued far into the latter. 



In the xylem of P. euphrasioides distinct growth-zones 

 were seen, each probably corresponding to one year's in- 

 crement. 



The thick roots and rhizomes in several of the Pedi- 

 cularis spp. certainly contain a considerable amount of 

 reserve food material, no doubt especially during the winter- 

 rest; the sweet taste of these organs in P. hirsuta and lanata 

 is well-known. In P. flammea^ Oederi and in the specimen 

 of P. hirsuta mentioned on page 462, which was collected in 

 late summer, I found the roots full of amylodextrin-starch. 



The condition of the material at my disposal did not 

 allow of a closer study of the haustoria. 



The Stem. As has frequently been pointed out (Hove- 

 LACQUE and Solereder) the absence of parenchyma-rays 

 from the part of the xylem formed by the cambium, is a 

 character widely distributed among the Scrophulariaceæ. 



Parenchyma-rays were also absent from all parts of the 

 shoot in the Veronica spp., Castilleia pallida, Euphrasia and 

 Bartschia alpina, and from the above-ground parts of the 

 axes in the Pedicularis spp. (in P. lapponica also from the 

 runners). In these cases the cambium very quickly develops 

 inwardly a continuous ring of vessels and wood-fibres, which 

 bridges over the leaf-gaps so that these become demonstrable 



