IOWA ACADEMY OF SCIENCE 
49 
BETULA (Tourn) L. 
293. Betula nigra L. Red or River Birch. Common along streams. 
294. Betula pendula Roth. White or Canoe Birch. A colony of young 
trees escaped from cultivation is established along Iowa 
River near Iowa City. 
FAGACEAE. 
QUERCUS (Tourn) L. 
295. Quercus alba L. White Oak. Common in woods. 
296. Quercus macrocar pa Michx. Burr Oak. Very common. 
297. Quercus bicolor Willd. Swamp White Oak. Rather scarce in 
woods. 
298. Quercus muhlenbergii Engelm. Chestnut Oak. Common on 
wooded hillsides. 
299. Quercus rubra E. Red Oak. Common. 
300. Quercus velutina Lam. Black Oak. Plenty in woodlands. 
301. Quercus imbricaria Michx. Shingle Oak. Rare. 
URTICACEAE. 
ULMUS (Tourn) L. 
302. TJlmus americana L. White Elm. Very abundant. 
303. TJlmus fulva Michx. Red or Slippery Elm. Abundant in wood- 
lands. 
CELTIS (Tourn) L. 
304. Celtis Occident alis L. blackberry. Common along streams. 
CANNABIS (Tourn) L. 
305. Cannabis sativa L. Hemp. Common in waste places, 
HUMULUS L. 
306. Rumulus lupulus L. Common Hops. Very abundant. 
MACLURA Nutt. 
307. Madura pomifera (Raf.) Schn. Osage Orange. Cultivated in 
hedges, etc. 
4 
