476 



LECTURE XXVIII. 



of parasitic Phanerogams ; so that in the Balanophorese, Rafflesiaceae, and perhaps 

 also in the Orobancheae, these reproductive shoots must first break through an 

 envelope of tissue when they begin to elongate (cf. Fig. i8, p. 28). Hovi^ever, the 

 matter requires further investigation, and the same holds good probably also of 

 certain growing-points of shoots in the Jungermannieae among the Liverworts, which 

 Leitgeb assumes to originate endogenously. 



Fig. 314 and 315.— Origin of a lateral shoot of Equtselum (after 

 Janczewski). Fig. 314 (above) earliest rudiment at A. Fig. 313 (below) 

 further developed bud k with origin of root w. In both figures st is 

 the intemode above the sheathing leaf sh (highly magnified). 



The endogenous mode of origin is, on the contrary, a general peculiarity of the 

 growing-points of roots; concerning which the most essential facts have already been 

 stated in the introductory lectures on Organography (p. 15). It is only necessary now 

 to make the additional remark that the young lateral roots only make their appearance 

 on the mother-root, as a rule, at a considerable distance from its growing-point. 

 This, however, does not prove that they did not already exist in embryo in the 



