536 . Rydberg : Notes on Rosaceae 



In the North American Flora, thirteen species of OpulastevdiXQ. 

 admitted. Of these, nine are previously known species, while four 

 are proposed as new. Of the more recently described species, 

 PJiysocarpiis micJiiganensis Daniels, and P. viissoiirie^isis Daniels, 

 were placed as synonyms under 0. opiilifolius and O. mtennedws, 

 respectively. The only distinctive character given by Daniels is 

 the pubescence, which is said to consist of stellate hairs in his two 

 new species ; while the two older species should have glabrous 

 leaves or pubescent ones with simple hairs. In none of the species 

 of this genus are the hairs normally simple ; only occasionally 

 simple hairs are found. While in 0. opulifolms the leaves are 

 usually glabrous or nearly so, they are in 0. intermedins usually 

 quite pubescent, .and the hairs commonly branched. If the 

 amount of pubescence should be regarded as a distinctive specific 

 character in Opidastcr, then Spiraea ribifolia Nutt., or Neillia 

 opiilifolia inidtiflora Durand, should be regarded as a distinct 

 species from O. capitatus, and 0. piibesccns Rydb. from O. nial- 

 vaceus (Greene) Kuntze. 



Spiraea ribifolia Nutt., the more glabrate form of 0. capitatus, 

 has often been confused with 0. opidifolius, and it is this form 

 that has caused the error of including the Pacific coast in the 

 range of 0. opidifolius, which is confined to the Alleghanian region. 

 The amount of pubescence is indeed of very little value, and the 

 only reliabl'e characters by which to distinguish the eastern species 

 from its western ally are the long caruncle in the former and the 

 different shapes of the leaves, especially those of the sterile shoots. 



As stated above, O. pubesceiis Rydb. is reduced to a synonym 

 of O. malvacetis. O. Ramaleyi A. Nelson is made a synonym of 

 O intermedins, while in my Flora of Colorado it was regarded as 

 the same as O. bracteatns Rydb. The first specimen cited by Nel- 

 son belongs to 0. bracteatns, but it does not agree with the 

 description of the carpels. All the other specimens cited agree 

 with said description, and these belong to O. iiiterniedins. 0. 

 Ramaleyi should therefore be regarded as the same as that species. 



The four new species described are : 0. australis, related to O. 

 opnlifolitis and 0. capitatus ; 0. cordatns, related to 0. intermedins ; 

 O. alabamensis, related to 0. stellatns ; and 0. Hapemanii, related 

 to O. monogynus. 



