THE AMERICAN BOTANIST 



145 



these in turn give rise to other flower buds until by the middle 

 of July, the plant may have four different sets of fruits which 

 have sprung from the original flower. Even then the fruits do 

 not fall off. They may continue to grow for several seasons 

 and are likely at any time to bud out new flowers and ripen 

 new fruits. In this way a cluster of a hundred or more fruits 

 belonging to from ten to fifteen generations may be formed. 

 A curious fact in this connection is that if one of these fruits* 

 be placed in moist soil it will develop roots and shoots and form 

 a new plant, but left on the parent plant, it produces only new 

 flower buds. While most plants drop their fruits at the end of 

 the growing season, there are some, notably certain pines and 

 eucalyptuses, which may retain them for a term of years, but 

 none of these continue growth and originate new fruits as the 

 cactus does. 



Flower Color. — Many students have doubtless observed 

 that one of the commonest flower colors is a sort of purplish 

 pink that often just misses becoming a distinct rose or a decided 

 red. As a matter of fact, good reds and pinks are compara- 

 tively rare in any flora and the reason for this is coming to 

 be well understood. The normal color of the pigment which 

 produces both red and blue flowers is this same purplish pink. 

 When the sap of the plant is alkaline this purplish pink turns 

 to blue and when it is acid the flowers become pink or red. 

 AVhen this is realized, several other peculiarities of flower color 

 become intelligible. For instance, there are many blue flowers, 

 such as the lungwort (Merfcnsia Virginica) which are pink 

 in the bud. As the flowers open and oxidation processes reduce 

 the acidity of the cell sap, the pink must of necessity become 

 blue. This also explains why so many blue flowers have pink 

 counterparts or the reverse. Let a strain with a tendency to 

 acid. cell sap appear in a race of blue flowers and its blossoms 

 are likely to become pink or red. The rose-colored variety of 



