THE AMERICAN BOTANIST. Ill 



sects. That such insignificant factors as insects could have 

 lifted the seed plants up to the highest point in plant evolu- 

 tion, does not seem improbable upon careful consideration. 

 So long as plants were aquatic, the male elements could reach 

 the eggs by swimming, but when plants ventured out on land 

 some other method of transferring the fertilizing bodies had 

 to be devised. The simpler species therefore, came to depend 

 upon the wind for this purpose, but the higher plants entered 

 into partnership with insects to the advantage of each. 



Catapult Seeds. — Those who stick pretty close to sys- 

 tematic botany are likely to think that family and even generic 

 likenesses are pretty closely confined to the flowers and fruits. 

 In reality a distinct plant family may have a large number of 

 other resemblances some of which may even be internal 

 as in the case of the production of inulin instead of starch as a 

 reserve food, in some groups or a particular form of color for 

 the flowers in others. Methods of seed dispersal tend to run 

 through entire plant families and sometimes extend to allied 

 orders. All the geraniums, for instance have some method 

 of slinging their seeds, and similar methods of seed dispersal 

 are found in the Oxalidaceae and Balsaminaceae. The not 

 distantly related Violaceae also propel their seeds. Curiously 

 enough each family mentioned secures the same end by a dif- 

 ferent method. The geraniums are the only ones that use a 

 sling for the purpose. The oxalises turn the ripened pod in- 

 side out with a jerk, the pods of the balsams, as in the well- 

 known touch-me-not, fly to pieces at the slightest jar, while 

 those of the violet slowly contract pinching out the seeds one 

 after the other as children sometimes shoot watermelon seeds 

 by pinching between thumb and finger. 



Leaf Adjustment in Oxalis. — The oxalis is the real 

 sensitive plant if by this we mean a plant so delicately bal- 

 anced between light and shade that a small change in the in- 

 tensity of either will cause it to make new adjustments of its 

 leaves. The plant is reported to have four ways of adapting 



