AMERICAN CINQUE-FOILS. 195 



most nitrogenous food, and near the flowers the nitrogen-catchers are 

 situated. 



Another peculiarity of P. arguta lies in its flowers, which are clus- 

 tered in large and conspicuous masses, and have petals that vary from 

 pale yellow to primrose or almost white. This is a very interesting 

 fact, because the native color of the potentillas is yellow ; but the 

 mountain species, and many other kinds, have varied to snow-white 

 blossoms ; and here we get a plant, as it were, in the intermediate or 

 undecided stage between the two colors. Notice, too, that P. arguta 

 is an herb of the rocky hill-sides, and therefore half-way toward be- 

 coming a mountain species. 



Now, on the summit of Mount Willard, just above the Notch of 

 the White Mountains, I found another very beautiful member of this 

 pretty group, the three-toothed cinque-foil {P. tridentatd). This is one 

 of your most northerly and mountain-loving potentillas, unknown in 

 Europe, inhabiting the coast of New England from Cape Cod north- 

 ward, and the mountain-tops of the great chains, from the Alleghanies 

 to the Maine ranges, as well as in Canada, Labrador, and the extreme 

 north of the continent. The three-toothed cinque-foil carries a step 

 farther the same characteristic, for its flowers are pure white, as so 

 often happens with mountain blossoms. Just in the same way, while 

 almost all lowland buttercups are golden yellow, some of the Alpine 

 buttercups are white as milk, and among these very potentillas there 

 are a few lovely snow-white mountain species in Europe and Asia. 

 One beautiful kind that I gathered on the Maritime Alps at Mentone 

 (P. saxifraga) has a blossom as delicately mountainous in type as the 

 saxifrages themselves, from which it takes its scientific name. 



Of course, I don't for a moment mean it to be understood that I 

 think P. tridentata is directly derived from P. arguta, or that the 

 latter species is now on its way to merge into the former. My Mount 

 Willard plant has palmate leaves of only three leaflets, while the com- 

 mon P. arguta of the northern hill-sides has pinnate leaves of from 

 three to nine cut-edged divisions ; and in many other technical points 

 they differ widely from one another. All I mean to suggest is merely 

 that the yellowish-white P. arguta is now just passing through a stage 

 which the ancestors of P. tridentata must have passed through long 

 ago. On the whole, to put it briefly, the potentillas are a yellow lot ; 

 but a few advanced members of the race are white ; and still fewer, 

 like the ornamental P. nepalensis and P. atropurpitrea of our gardens, 

 are crimson, scarlet, or bright red. So far as I know, no potentilla is 

 ever blue, which is the highest level of floral coloration. 



The three-toothed cinque-foil has an almost shrubby and woody 

 root-stock, and displays a tendency to assume the character of a true 

 shrub. But its northern habitat and mountain manners keep it low 

 and tufted, after the common fashion of upland vegetation. There is 

 another of its kind, however {P. fruticosa), which really grows into a 



