1 20 ROSACEAE 



species is marked by the fact that the styles of the pistils co- 

 here in a column. The fruit, which is red, matures in autumn 

 and is glandular-hispid, pear shaped to subglobose, and about 

 one-third inch in diameter. 



Distribution. — The Prairie Rose prefers relatively open 

 situations along fences and roadsides, in clearings, and in open 

 woods. In such places it grows from Ohio to Florida and 

 west to Kansas. In Illinois, it is common and abundant. It 

 has been reported from all parts of the state and seemingly 

 from all kinds of situations except dense woods. It is one 

 of the most beautiful of the wild roses and is one of the 

 species from which valuable cultivated climbing roses have 

 been derived. 



Forms of this rose distinguished by more or less dense pu- 

 bescence on the under surface of the leaves and with leaflets 

 which are as a rule thicker and have a harsher appearance are 

 segregated as the variety tomentosa Torrey & Gray. 



ROSA PALUSTRIS Marshall 

 Swamp Rose 



The Swamp Rose, fig. 27, is a shrub with erect, smooth stems 

 generally 2 to 6 feet high that are armed with numerous prickles, 

 which are limited to non-flowering stems on some specimens. 

 These prickles are recurved and generally flattened at the base, 

 sometimes quite eccentric and strongly decurrent on the stems, 

 and arranged singly except on new shoots, where they often 

 occur in pairs below the leaves. IVIost leaves have 7 leaflets, 

 but sometimes there are 5 or 9. The leaflets are lance-elliptic 

 to broadly elliptic and up to 3 inches long by I14 inches wide, 

 though usually only about half that size. Lateral leaflets are 

 sessile or nearly so, but terminal leaflets are supported on a' 

 stalk almost Yi inch long. They are narrowed at the base and 

 generally acute at the apex, though sometimes rounded, and the 

 margins are finely serrate nearly to the base. The surface is 

 smooth or nearly so above and hairy beneath, though sometimes 

 only on the veins. Both petioles and rachises are pubescent and 

 sometimes prickly. The stipules are narrow, commonly with 

 involute edges, and Yi to II/4 inches long. 



The flowers, deep rose in color, up to 2 inches wide, which 

 blossom from late in June through July, are in corymbs or 



