THK STEM OR SHOOT. 



105 



character speaking in favour of its shoot-natnre. The 

 leafless character affords no argument against this idea ; 

 several cases are known of shoots which have, for the 

 purpose of some special function, lost the power of 

 forming leaves, either over the whole or a part of 

 their length, e. g., the rhizomes of Psilotacese, the 

 inflorescences of Cruciferse, the shoots of Trichomanes 

 membranaceum" 



" Pfeffer has placed on record some most interesting 

 observations in which rhizophores of certain species 

 (e. g., 8. inaequalifolia) develop spontaneously into leafy 

 shoots. 



" 1 have myself recently observed the same pheno- 

 menon in the case of the above-mentioned species in 

 the Fern-house at Kew. In the case of one shoot 

 which I may take as a typical example, of the two 

 rhizophores at one fork of the stem, that on the lower 

 surface was perfectly normal and elongated, and with 

 the usual dark-brown colouration, the upper one was 

 very short and changed into a leafy shoot ; at the next 

 node the upper rhizophore was a leafy shoot and 

 growing almost horizontally : at the next the lower 

 rhizophore was much elongated, growing downwards, 

 and with leaves somewhat sparsely scattered along its 

 whole length ; the tip was becoming green, the rest 

 being dark-brown, and it was just beginning to bend 

 upwards, while at intervals along its course it bore a 

 short leafy branch (this rhizophore represents an 

 interesting transitional form between the normal organ 

 and the rhizophore transformed into a leafy shoot) ; 

 at the next node the lower rhizophore is a very short 

 leafy shoot and there is no upper one ; at the next the 

 only rhizophore present, viz., the lower one, is a leafy 

 shoot which at first began to grow downwards but 

 soon bent upwards sharply ; it therefore also repre- 

 sents a more or less intermediate stage of transition. 



"On other shoots the transformed rhizophores were 

 much less half-hearted ; many of them at once grew 

 quite vertically upwards into typical leafy shoots, each 



