METAMORPHOSIS. 89 



one season a thorn, the next a branch, one year the rose is 

 double, full, and perfect as to petals, the next year a bud 

 usurps the stamens and pistils; now these are all irregular 

 viefamorphoses. 



236. Regular metamorpJiosis is the change we see going 

 on in regular sequence, governed by laws that act with 

 precision, unless controlled directly by some of those agents 

 just alluded to as producing irregular metamorphoses. 



237. This change botanists pronounce to be the result 

 of two forces, expansion and contraction. The plumula 

 expands into a stem, the radicle into root, the stem into 

 branches, and the branches into leaves ; the leaf contracts 

 into bracts, the bracts into calyx, the calyx into the corolla, 

 which expands into fruit or contracts into seed. Irregular 

 metamorphosis can be easily demonstrated by experiment; 

 the single poppy, for instance, can be made perfectly double 

 in two or three years by proper cultivation. To witness 

 regular metamorphosis you have but to follow any plant 

 through its different stages of germination, growth, flower- 

 ing, and seeding. 



238. The expansion into leaves and contraction into 

 flowers is prettily shown in the hoya, common wax-vine. 

 Take two. slips, put one in a large pot with plenty of rich 

 soil, and supply it abundantly with water, and you will have 

 a large vigorous vine, with a superabundance of green 

 leaves, but no flowers ; place the other in a small jar, scantily 

 supplied with nourishment, and you will have a small vine, 

 few leaves, and large and beautiful clusters of flowers. 

 You will, perhaps, be sui-prised to hear that it w^as a poet 

 and not a philosopher that made this discovery. Goethe 

 has embodied his history of metamorphosis in a poem, the 

 beauty of which will make you excuse its length. So, 



236. What is regular metamorphosis ? 



237. To what are these changes due ? Explain the process. What of irregular 

 metamorphosis ? 



238. niustrate the expansion into leaves and contractiou into flowers. Who 

 made this discovery ? 



