ENATION. 



445 



place an anomalous development which occurs occasion- 

 ally in Bnscus aculeatus, and in which, from the upper 

 surface of the ordinary flattened leaf-like branch, pro- 

 jects at right angles a second similar branch, so that 

 in section the appearance would be hke that of the in- 

 verted letter t; thus, jj. 



Enation from foliar organs Leaves. The development of 

 adventitious lobes from leaves may take place either 

 from their surfaces or their margins. A few illustrations 

 may be given of each. In cabbage leaves a formation 

 of adventitious laminse projecting at right angles fi^om 

 the primary one may frequently be observed. In the 

 instance figured (fig. 210) the new growths proceeded 



Fig. 210.- Section thi-ough base of midiib of cabbage leaf, showing 

 supplementary laminae, &c. 



almost exclusively from the thick midrib, which, in the 

 figure, is shown cut through just above the base. Not 

 only is the ordinary semilunar band of vascular tissue 

 to be here seen, but a similar broken line of vessels 

 exists on the upper side of the leaf-stalk ; thus the 

 whole structure resembles that of a stem or a branch 

 as much as that of a true leaf. 



The development of secondary leaves from the sur- 

 faces of primary ones (phyllomania, autophyllogeny) 

 has already been alluded to at p. 355. 



