RUDIMENTARY ORGANS. 



event under our own eyes, and under the common conditions 

 of plant life. The natural order of plants to which Snapdragon 

 belongs presents a peculiarity, inasmuch as, in most of its members 

 one of the five stamens is abortive or rudimentary. It should 

 be borne in mind that the botanist possesses a highly interesting 

 and exact method of ascertaining how many parts or organs should 

 be represented in plants. He places his reliance in this respect on the 

 working of what may be called the " law of symmetry." The operation 

 of this law, which may be said to be founded on wide experience, 

 tends to produce a correspondence in numbers between the parts in 

 the four sets of organs of which we have just noted a flower to be 

 composed. Thus, when we count five parts in the green calyx of a 

 plant, we expect to find five blossoms (or petals) in its corolla ; five 

 stamens (or some multiple of five), and five parts (or some multiple 

 of that number) in the pistil. Where there appears to be a lack of this 

 numerical correspondence, the botanist concludes that some violation 

 of the law of symmetry has taken place, and that some parts or organs 

 which should normally have been developed have been altered or 

 suppressed. His reasoning, in fact, proceeds on the plain basis of first 

 establishing, through experience, the normal number and condition of 

 parts in the flower of any given order of plants, and of thereafter 

 accounting by suppression or non-development for the absence of 

 parts he expected to have been represented. 



Now, in the Snapdragon tribe we find, as a general rule, five parts 

 in the calyx, five petals in the corolla, but only four stamens. Such 

 a condition of matters is well seen in the flower of frog's- mouth 

 (Antirrhinum), where we find four stamens, two being long and two 

 short (Fig. 24, A, s l s 2 ), as the comple- 

 ment of the flower. We account for 

 the absence of a fifth stamen by say- 

 ing it is abortive ; and the rudiment 

 of this missing stamen may also be 

 found in the flower. But a natural 

 reflection arises at this point, in the 

 form of the query, Have we any 

 means of ascertaining if our ex? 

 pectation that a fifth stamen should 

 be developed is rational and well 

 founded? May not the plant, in 

 other words, have been " created 

 so"? Fortunately for science, na- 

 ture gives us a clue to the discovery 

 of the truth in this as in many other cases. In one genus of 

 these plants (Scrophularia) we find a rudiment of a fifth stamen 

 (Fig. 24, B s); and in Snapdragon itself this fifth stamen becomes 



G 2 



FIG. 34. FLOWER OF FROG'S-MOUTH. 



A, Flower of Frog's r mouth ; B, Flower of 



Figwort or Scrophulai ia. 



