224 



The Journal of Hkrkoitv 



A CASE OF "DEMI-REVERSION" 



This supposedly spineless Opuntia from the Island of Malta, when planted at Chico, Cali- 

 fornia, began to develop spines — but only nn a part of the plant. Sections taken from the 

 spiny part produce spiny plants; cuttings from the sjiineless side produce plants which are 

 spineless. Mr. Griffiths considers this to be a case of reversion which indicates that the 

 original ancestor of the modern Opuntias was spiny. (Fig. 14.) 



ground when the planting was done all 

 made a very poor growth. Ilowc'\-cr, 

 the small amount of growth that was 

 made came true to the characters of the 

 individual cuttings planted. In the 

 spring of 1912 the previous season's 

 growth was again sjiiny on one side of 

 the plant and spineless on the other, 

 the contrast i)roducing a very striking 

 ai)i)earancc. 



This habit of reversion or l)ud varia- 

 tion, whichever it may be considered. 



is a very imjiortant characteristic, and, 

 while more striking in the above variety 

 than any other which has lieen cultivated 

 in these investigations, apjjcars to be 

 not at all uncommon. A jilant of 

 another spineless variety on hand now 

 bears promise to be just as consi)icuoLis 

 a few years hence as this one. It 

 started to vary in the same direction last 

 year. 



All this relates, however, to the devel- 

 opment of characters economically un- 



