OF NORTH AMERICA. 73 



bly a peculiar species near to my Sp. crenata, 

 as it cannot be Sp. italica ! It must be better 

 described, and may be called Sp. kookeriana 

 R. It is akin to Sp. jdponica. I hope to have 

 thus ascertained many obscure or lost species, 

 and elucidated the whole genus ; in order to 

 remove the difficulties I have been compelled 

 to introduce some species not strictly Ameri- 

 can, but have greatly increased ours also. This 

 will conclude the true G. Spirea, I shall now 

 describe the akin blended Genera. 



667. PHYSOCARPA Raf. subg. of Ser. 



(or Physotheca.) Diff. Spirea, calix deeply 5fid, 



pistils 3 united at base, capsules 3 coalescent 



swelled smooth, apex free bivalve, leaves lobed, 



flowers in short corymbose racemes bractea- 



ted Thus it differs as much as Gillenia but 

 has not a tubular calix. 



668. PHYSOC. RIPARIA Raf. Spirea opulifo- 

 lia L. <J*c. Var. tomentella Dec. Beck. Branch- 

 es angular pale, leaves petiolate ovate rounded 

 or oblong unequaly serrate often lobed or trifid 

 acute quite smooth, beneath pale trinervate, 

 corymbs terminal, bracts oblong or laciniate, 

 pedicles filiform pubescent, calix tomentose 

 acute, capsules smooth much swelled From 

 Canada to Carolina, Louisiana and Missouri, 

 on the banks of streams. Shrub 5 to 10 feet 

 high, leaves 2 or 3 inches long, flowers white 

 with pink shades, capsules fulvous or fuscate, 

 seeds rounded yellowish. This has always been 

 deemed the Sp. opulifolia by our botanists, and 

 it was really that of Linneus, since he gives A- 

 merica as its only locality ; but now many 

 others must be separated. Var. 1. parmfolia, 

 2. arborea. 



669. PHYSOC. OPULIFOLIA or GLABRA Raf. Sp. 



10 



