THE AMERICAN BOTANIST 71 



soviri River roses about Mobridge seem to be the same species, 

 only not so thrifty. In the woodlands along the Minnesota 

 River at Montevideo there grows what is known as the 

 "timber rose," and it has always passed as Rosa hlanda Ait, 

 in the state reports. The range of Rosa hlanda has been en- 

 larged in the Seventh Edition of Gray's manual so as to in- 

 due Missouri and Assiniboia, but Bush's specimen from Mis- 

 souri bears little resemblance to the "timber rose" rose that we 

 have here. The flowers on our roses are usually single at the 

 ends of the branches, occurring sometimes in twos and threes. 

 The stems of our timber rose are almost always covered with 

 weak deciduous prickles which fall away with age, the stems 

 becoming gray. The branches are often free from prickles, 

 and there are no infrastipular spines. I have the impression 

 that the flowers are more often corymbose in the true Rosa 

 blaiida. Perhaps the rose of our woodlands is Rosa Sayi 

 Schwein. Along the edges of the woods there are doubtless 

 natural hybrids between this rose and Rosa pratincola Greene, 

 the common wild rose of the prairies. 



Botanical specimens of roses should always include a ver- 

 tical slice from the stem, especially from the older stems, as 

 well as the flowers and, what is more important, the fruit. 



M\ontevideo, Minn. 



THE YELLOW BUTTERFLY WEED. 



By Willard N. Clute. 



Anyone who lives near a stretch of sterile soil is likely to 

 be acquainted with the butterfly weed or pleurisy root (^^- 

 clepias tiiherosa). It seems especially fitted to endure the 

 drouth conditions of sand barrens and clayey hillsides and in 

 such situations its flat-topped umbels of orange red flowers 

 unobscured by the sparse vegation inhabiting such places, 

 makes it one of the most conspicuous of plants for some weeks 

 following midsummer. 



