THE ANGIOSPERMAE : STEMS 



925 



also by the presence of opposed bracts in the related genus Dana'e, where the 

 inflorescence is free from the cladode. A third theory interprets the whole 

 cladode as a modified leaf, borne on an axillary shoot, to w^hich it is united 

 along its lower half. 



Fig. 907. — Ruscus aculeatus. Shoot with 

 cladodes bearing flower buds. 



The common Asparagus {A. officinalis) has cladodes which appear from 

 the axil of each scale leaf as two little bundles of green needles. Comparison 

 of the placing of these, relative to the scale leaf, with the arrangement of the 

 flowers at flowering nodes, makes it very probable that they represent sterilized 

 flower stalks arranged in two cymes. They do, in fact, occasionally bear 

 abortive flower buds at their ends (Fig. 908). 



The median axillary shoot, present at the flowering nodes, is suppressed 

 at the vegetative nodes, but in the allied genus Myrsiphyllum (Climbing 

 Asparagus) it is present and is developed into a leaf-like cladode, instead of 

 the needles of the common Asparagus, which in this case are suppressed. 



As true phylloclades in our present sense, we may cite several cases in 

 which the whole of a shoot or indeed all the shoots of the plant are flattened 

 and leaf-like. Perhaps the best known is the Cactus called Opiwtia (Prickly 



