142 FUNCTIONS OF CLIMBING ROOTS OF IVY 



the climbing rootlets, and different in structure from them, 

 or are they climbing rootlets altered and developed ? It is 

 difficult to determine with certainty from the specimen, but 

 apparently it shows fibres in every stage of development, 

 from hairs to thick root-like processes. In the case of ivy 

 upon trees, whose stems have been separated, the ivy always 

 dies, I believe, because no nourishment is obtainable from 

 the tree ; but in the instance before us the struggle of the 

 ivy for life has evidently depended upon its powers of 

 penetrating and developing roots in the masonry. The 

 attempt has evidently been successful, though of course 

 within limits, but on the whole I thiuk that my specimen 

 is a nice example of the balancing of forces in the struggle 

 for existence. 



I think that the views of authorities on my subject may 

 be interesting. 



*' The stem of the ivy is attached by dense tufted fibres, 

 which serve for support, not for nourishment." — Smith's 

 English Flora, 1824. 



"The aerial roots of ivy are simply processes intended for 

 mechanical support." — Professor J. H. Balfour. 



"The climbing roots of ivy are physiologically different 

 from true roots." — Prantl and Vines, 1886. 



" Roots are usually buried in the soil, but they may be 

 aerial, as in ivy." — Chambers's Encyclopedia, 1891. 



" If we detach a portion of the stem (of ivy) on which 

 climbing root-like processes have just begun to appear in a 

 tender and pellucid condition, and lay it on damp moss in 

 a shady place, it will be found that the claws begin imme- 

 diately to lengthen into true roots, and ramify through the 

 moss in search of nourishment, and if left alone will soon 

 sustain the cutting as an independent plant. The tufted 

 fibres must therefore be true roots which have been arrested 

 in the process of development, but become developed, and 

 penetrate far into masonry to which the plant clings, to 

 provide for it whenever an accident shall result in isolation. 

 Interesting examples of ivy as an aerial plant may be 

 observed at Hadleigh Castle, near Southend, Essex, and on 

 the old walls of Conway." — Shirley Hibberd in The Ivy, 1872 

 — an instructive and interesting illustrated monograph. 



