Scrophulariaceae. 503 



on the inner side of the xylem-ring only as thinner portions 

 of the latter among 'les faisceaux reparateurs". 



A transverse section of the rhizome in P. siidetica, 

 Sceptriim carolmiim, hirsuta, lanata, flammea and Oederi 

 showed, on the other hånd, a circle of vascular bundles 

 mutually separated by parenchyma-rays, as is commonly 

 the case in fleshy dicotyledonous rhizomes, especially such 

 as are abiindantly covered with leaves. With respect to 

 P. Sceptriim caroliniim this feature has been already described 

 and figured by Chatin.^ In P.capitata the runners had two 

 rather broad diametrically opposite parenchyma-rays. 



In the above-ground parts of the axes in the Pedicularis 

 spp. the peripheral portions of the pith consisted usually 

 of thickened, lignified and porose cells; this was most decided- 

 ly the case in P. Sceptriim caroliniim, in the up to one- 

 metre-high stem of which the stereom is, on the whole, very 

 vigorously developed. When an elongation of the axis takes 

 place during flowering and fruitsetting, the lignification of 

 the stereom naturally does not begin until this is accom- 

 pHshed. The central portions of the pith are very thin-walled 

 and die a\vay early. 



Hard bast was present in the periphery of the stele in 

 Veronica jruticans, and very abundantly in the above-ground 

 parts of the axis in Bartschia alpina; in the rhizome of the 

 latter species the hard bast was present more sparingly, and 

 sometimes totally absent. 



Continued gro^Uh in thickness through several growi^h- 

 periods could be observed in the persistent basal portions 

 of the shoots of the two Arctic species of Veronica (in V. 

 friiticans the growth in thickness is continued throughout 

 many years — as many as 16 were counted), in Castilleia 



1 Ciiatin: Anatomie comparée des vegetaux. Plantes parasites. 

 Dicotvlédones. P. 192. PL XLII. 



