POTENTILLA FRUTICOSA. SHRUBBY CINQUE-FOIL. 115 



force is about to be arrested by reproductive force, only five 

 are formed, and then, successively, only three, two, and one. 

 Thus it appears that the rapid convolutions, which end in the 

 verticils forming the flowers, occur only when the growth-force 

 has been reduced to the production of single leaflets instead of 

 full leaves. If the same thing were to occur before, at the three 

 or five leafleted condition, the probability is that the petals would 

 each be three or five lobed instead of entire, as we see them 

 now. There is also some special interest in the calyx, which, 

 as we have said, is composed of a double verticil of five leaves 

 each. The outer set remains somewhat spreading, but the inner 

 is bent inwards, making a slight covering for the naked seeds 

 (Fig. 3). The result is a very pretty design for ornamental 

 work, as shown in our full-face view of the capsule in Fig. 2. 

 The seeds in this species of Cinque-foil have likewise a special 

 interest of their own. In some of the allied Potcntillas, the 

 styles are thickened upwards, being what is technically called 

 " clavate " or " club-shaped " ; but our species, with a few others, 

 has them filiform, so that, after the petals have fallen, the seeds 

 look as if they were covered by a growth of thin hair. On this 

 account, Torrey and Gray grouped these species together in a 

 separate subdivision, with the expressive name, Comocarpa, — 

 coma signifying a head of hair. 



Potent ilia fniticosa is also interesting from a geographical 

 point of view. It is widely diffused over the northern regions; 

 and if we allow the several forms alluded to above to be simply 

 varieties of the same species, we may say that it makes a circuit 

 completely round the globe. It is abundant in Maine, Massa- 

 chusetts, and Connecticut, decreasing in extent through New 

 York till it reaches a southern limit in Northwestern New 

 Jersey. We know of no locality where it is wild in Pennsyl- 

 vania, although not uncommon there in half-cultivated places. 

 In its New England locations, it seems to prefer low, wet 

 meadows. In Ohio, it is found in dryer situations. \\ hen it 

 reaches Michigan, it loves to grow amom>- the sand on the lake 



