THK AMP:RICAN BOTANIST 111 



V\n>u examining a number of llowcrs, vvc find tliat they 

 fall into two vvell-definccl groups according to the number of 

 the parts in each floral set. The numbers are three, four and 

 fi\ e. The number of parts might seem to be an unstable 

 thing to base a division upon, but the fact is that these 

 numbers are practically unvarying in each kind of flower, and 

 tliat other characteristics, as well marked, accompany them. 

 For instance, the three-parted flowers have, a single seed-leaf, 

 scattered vascular bundles, and parallel-veined leaves, while 

 t!ic others have two seed leaves, bundles in circles, and net- 

 veined leaves. Such a distinction, therefore will divide the 

 flowering i)lants into two distinct groups, which are common- 

 ly called monocots and dicots according to the number of 

 seed leaves they possess. Probably all can look back to their 

 early days of botanizing and recall how carefully they read 

 the distinctions between monocots and dicots in their key, and 

 how after a few weeks of such investigations thev recognized 

 the differences at sight and started with the group to which 

 the specimen in hand belonged. Older students naturally 

 recognize lesser groups in the same way and begin still far- 

 ther along in the key. 



A favorite distinction depended upon to separate the 

 large plant groups into smaller ones, is the nature of the cor- 

 olla. In some plants the petals are united into a saucer, tube 

 or cup. while in others they are entirely separate and free. 

 Tlie ovary also offers easily recognized distinctions, some- 

 times being borne within the flower and sometimes appearing 

 to grow below it. The important fact is, that following such 

 divisions we find our groups essentially alike. The flowers 

 often become irregular by having some petals of different 

 size from the others, and these latter almost invariablv have 

 the habit of turning sidewisc. Their stamens are also great- 



