HOPS BLOSSOM. 161 



leaflets, inclosing an equal number of elastic stamens. 

 Contrary to the usual rule in flowers, the stamens are ar- 

 ranged opposite to the calyx scales, instead of alternately 

 with them a fact which shows that a row of petals, once 

 intermediate between stamens and calyx, has been sup- 

 pressed by disuse, owing to the acquisition by the flowers 

 of the habit of wind-fertilization. For, normally speak- 

 ing, all the successive rows in flowers are arranged al- 

 ternately with one another, as anybody may see in a 

 moment by looking at a fuchsia or a strawberry blossom ; 

 but when the petals are lost through change of habit the 

 other whorls appear to stand opposite to one another, 

 though the real nature of their arrangement is always 

 preserved for us in intermediate forms, with very small 

 petals, which are occasionally entirely wanting. By 

 these and numerous other minute agreements in points 

 of structure, the nettles, hops, and pellitories are all seen 

 to be descendants of a single common ancestor, which 

 had already lost its petals and had separated its sexes in 

 different flowers, but had not yet, of course, acquired 

 any of the special chracteristics that mark off the nettles, 

 the hops, and the pellitories from one another. 



On the other hand, the hop itself must very early 

 have begun its own special differentiation from this old 

 central generalized form ; or else it would not now 

 exhibit so many points of minute adaptation to its own 

 peculiar habitat, nor would it be so distinctly marked 

 off from its other divergent relatives on either side. 

 While all of the nettles are mere soft herbs, and most of 

 the pellitories are slightly shrubby weeds, the hop has 

 acquired the habit of producing a stout perennial root- 

 stock ; from which each spring it sends up wonderfully 

 long annual stems, that climb to an immense height over 

 the poles in cultivation or over bushes and thickets in 



