184 



PRINCIPLES OF PLANT-TERATOLOGY. 



occurs) was the terminal leaflet developed as a tendril, 

 but all the lateral leaflets as well. 



Noll observed a well-nigh inexplicable transforma- 

 tion in the canary-creeper (Tropseolum advmcuni) in 

 which one of the leaves, viz., the fifth, was changed 

 into a tendril, the more remarkable inasmuch as this 

 plant has no tendril-forming relatives whatsoever ; the 

 petiole, however, possesses the power of twining round 

 supports, and if we suppose the leaf-blade to become 

 reduced to nil, a tendril-like organ would be the result. 



3. Bracteody of Foliage-leaves. — A rare pheno- 

 menon. In the arum lily (Bichardia xthiopica), B. 

 Elliottiana, and the cuckoo-pint (Arum macidatum) one 

 or two extra spathes may occur, a phenomenon due to 

 the transformation of one or more foliaere-leaves and 

 the insertion of these at a much higher level on the 

 stem ; the extra spathes may exactly resemble the 

 normal one, or may be partly coloured and partly 

 green and leaf-like, and either of the same size as the 

 normal spathe or intermediate in size between that 

 and the leaf (PI. XVII, fig. 3). 



In Narcissus biflorus a foliage-leaf became fused 

 with the scape along the latter' s entire length; half 

 of the leaf was membranous in consistence, viz., that 

 portion of it which helped to ensheathe the flowers. 



Under this heading may be cited the conclusions 

 which Velenovsky and Danek have reached with 

 regard to the terminal portion of the fertile cladode of 

 Buscus, viz., that it represents the anterior of the pair 

 of bracts which has become fused with the two pro- 

 jecting wings of the cladode, and at the same time 

 much enlarged and cladode-like. If this is so, this 

 bract may be regarded as having become foliaceous. 

 Both authors observed abnormal cases in which this 

 bract (according to their view) had become scale-like, 

 altogether like the normal posterior one, both in size, 

 consistence, and position. It is doubtful, however, if 

 this interpretation of the fertile cladode is correct. 



4. Petalody of Foliage-leaves. — Quite as peculiar 



