536 Rydberg : Notes on Rosaceae 



Opulaster 



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

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



'P 



missouriensis Daniels, 



ipidifoliu 



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. opulifolius the leaves are 

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

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

 amount of pubescence should be regarded as a distinctive specific 

 character in Opulaster, then Spiraea ribifolia Nutt., or Net 

 opidifolia midtiflora Durand, should be regarded as a distinct 

 species from 0. capitatus, and 0. pubescens Rydb. from 0. wa - 







vaceus (Greene) Kuntze. 



ipitatus, 



Spiraea ribifolia Nutt., the more glabrate torm oi la t 

 has often been confused with 0. opulifolius, and it is this orm 

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

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

 The amount of pubescence is indeed of very little value, an 

 only reliable characters by which to distinguish the eastern specif 

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

 different shapes of the leaves, especially those of the sterile 



/ 



, _ . g loescens Ryuu. is iwuv ^ 



of O. malvaceus. O. Ramaleyi A. Nelson is made a synonym ^ 

 0. intermedins, while in my Flora of Colorado it was regar ^ 

 the same as 0. bracteatus Rydb. The first specimen cited y ^ 

 son belongs to 0. bracteatus, but it does not agree w 

 description of the carpels. All the other specimens cifc : J»g ^ 

 with said description, and these belong to 0. intermet 

 Ramaleyi should therefore be regarded as the same as that sp ^ ^ 

 The four new species described are : 0. australis, re ^ 



opulifolius and O. capitatus; 0. cordatus, related to 0. inierm ^ 





ecies 

 



0. stellatus ; and 0. Hap 



to 0. monogyuus. 



