t 

 144 The Ottawa Naturalist. [Feb. 



markable is the tendency some of the leaves exhibit to lobate 

 after the manner of P. trifoliata. But this tendency is checked 

 in some way in its action, as it succeeds in affecting onl}^ one- 

 half of the leaf, thus showing that the elementary characters of 

 P. raceniosa are dominant over those of P. trifoliata. 



In the three plants the leaves are bordered with glandular 

 teeth. 



Flower and Fruit. 



The color of the ray-flowers of P. mainensis is evidently 

 intermediate between the pale purple of P. racemosa and the 

 straw yellow of P. trifoliata. 



The inner bracts of the involucre are about the same in 

 outline in the three plants, but they differ mtich in the amount 

 of pubescence. In P. trifoliata these bracts are perfectly 

 glabrous ; in P. racemosa they are covered with very long ribbon- 

 like flattened hair tipped with a spherical gland; P. mainensis 

 shows a pubescence much like that of P. racemosa, but very 

 scarce, the evident result of the fusing of opposed characters. 



The bract of P. mainensis ends in a somewhat fimbriate 

 obtuse point bearing septate hair, very different from those 

 described above; they are much shorter, and consist in a single 

 line of hyaline cells. The bracts of P. trifoliata and P. racemosa 

 show the same peculiarity. 



The bracts of P. racemosa and P. mainensis are covered 

 with truncate conical papillae, inclined towards the point of 

 the bract. Every cell being papilla-bearing, their number can 

 be estimated in round figtires to 10,000 per sq. mm. None of 

 the twenty specimens of P. trifoliata from the halophytic habitat 

 of Anse a Persi showed these papillae, but we found them in 

 smaller numbers, and different in form, on a giant specimen 

 collected on the qviartzite rocks of the " Gros Pelerin," one of 

 the islands off the Kamotiraska coast. 



The akene of P. mainensis is slightly longer than that of 

 P. racemosa, and much longer than that of P. trifoliata, even 

 when giant specimens of the latter are considered. 



Distribution. 



We do not believe that P. mainensis has been before noted 

 outside of the type station on the St. John's River, neither do 

 we think it can be found frequently on account of the distri- 

 bution of the parent species and their different habitat. 



P. racemosa is very widely distributed in North America, 

 from Eastern Quebec to Alberta, whilst P. trifoliata is distinctly 

 eastern and boreal. In the Province of Quebec there is no sure 

 record west of "Gros Pelerin" island, though some of Macoun's 



