THE STEM OB SHOOT. 



131 



shoots all round the stem- base ; each shoot is a 

 slender structure bearing rudimentary leaves. This 

 curious phenomenon has occurred in two species of 

 mullein ( Verhascum nigrum and V. pyramidatum) . 



Then there is the phenomenon of shoots arising from 

 the pith. In a decapitated stem of the Cycad Stangeria 

 paradoxa, from the centre of the pith grew out a 

 young leafy shoot. 



Berkeley figures a similar case in the sea-kale 

 (Crambe maritima) where a number of buds were 

 springing from the pith. 



A figure is given on the previ- 

 ous page (fig. 35) of adventitious 

 shoots bearing tubers springing 

 from the internal tissue (the pith) ^Nk^7- <r&/ 

 of a potato, and bursting through to 

 the outside. Various authors also 

 describe this phenomenon, which 

 seems to be usually ascribed to the 

 rubbing off of the external buds or 

 eyes. Carriere also induced it by 

 removal of the external surface. 

 Hence it would seem that in this 

 case also mutilation, accidental 

 or purposive, is the cause of the 

 phenomenon. 



Instances are also known of shoots arising from the 

 hypocotyl. There are several species of Linaria which 

 regularly multiply by the development of shoots grow- 

 ing directly out of the hypocotyl ; these at first form 

 an elongated leafless portion resembling the hypocotyl 

 itself before giving rise to leaves and flowers (fig. 36). 



Jensen describes the formation, as the result of injury 

 to the epicotyl, of buds from the hypocotyl of Jatropha 

 curcas. 



Fig. 36. — Linaria armaria. 

 Adventitious shoot (as) 

 growing from hypocotyl. 

 (After Bernhardt) cot., 

 cotyledons. 



Leaf-Shoots. 



These also are of extreme frequency. Just as 

 adventitious shoots on roots have become, in such cases 



