676 Mutations 



has broad elliptical undivided leaves. On 

 the middle of the midvein these leaves are seen 

 to bear small clusters of flowers; indeed this 

 is the only place where flowers are produced. 

 Each cluster has from 13 - 15 flowers, of which 

 some are staminate and borne on stalks, while 

 others are pistillate and nearlj^ sessile. These 

 flowers are small and of a pale greenish color 

 and yield small stone-fruits, with a thin 

 coating of pulpy tissue. As the name indicates, 

 this mode of flowering is closely similar to that 

 of RusGus, which however, does not bear its 

 flowers and berries on real leaves, but on leaf- 

 like expansions of the twigs. Phyllonoma rus- 

 cifolia, a saxifragaceous plant, bears the same 

 specific name, indicating a similar origin of the 

 flowers. Other instances have been collected by 

 Casimir de Candolle, but their number is very 

 small. 



As a varietal mark, flowers on leaves like- 

 wise rarely occur. One instance however, is 

 very remarkable, and we have already dealt 

 with it, when treating of constant varieties, and 

 of the lack of vicinism in the case of species 

 with exclusive self-fertilization. 



It is the '* Nepaul-barley " or Hordeum tri- 

 furcatum. The leaves, which in this case bear 

 the adventitious flowers, are the inner scales of 

 tlie spikelets, but not on green leaves as in the 



