328 IOWA ACADEMY OP SCIENCE 



Bat nidi ium aquatile (L.) Wimm. A large flowered form was 

 found in a pool along the Umatilla. 



Ranunculus sceleratus L. Frequent along the Umatilla. 



Ranunculus Cymbalaria Pursh. Abundant in wet places. 



Roripa nasturtium (L.) Rusby. Common along the Umatilla. 



Roripa columbiae Suks. Scarce ; a few specimens found in mud 

 along the Columbia. 



Roripa curvisiliqua (Hook.) Bessey. Frequent in damp ground. 



Roripa obtusa (Nutt.) Britt. Infrequent, in mud along the 

 Columbia. 



Sisymbrium altissimum L. Very abundant and generally dis- 

 tributed, being found nearly everywhere in the desert. 



Sisymbrium canesens Nutt. Occasional along the Umatilla. 

 Bursa bursapastoris (L.) Weber. Common about houses. 

 Lepidvum medium Greene. Abundant in slightly moist ground. 



Cleome lutea Hook. One of the most conspicuous plants of the 

 region. It grows in great abundance on drifting sand, 

 attaining a height of five to six feet, with stems an inch in 

 diameter. 



Ribes aureum Pursh. Found in a few places along the Uma- 

 tilla. 



Rosa pisocarpa Gray. Common along the Umatilla. 



Potentilla rivalis Nutt. Common in damp places along the 

 Umatilla. 



Potentilla permollis Ryd. One specimen, near the Umatilla. 



Kunzia tridentata (Pursh.) Spreng. Common and quite gen- 

 erally distributed in the desert. It is mostly dwarfed and 

 depressed. 



Crataegus brevispina (Dougl.) Heller. Quite plentiful along 

 the Umatilla, where in places it forms dense thickets. 



Petalostemum ornatum Dougl. Common and generally dis- 

 tributed in dry ground. 



Melilotus al bus Desr. Extremely abundant in moist ground, 

 especially along irrigating ditches. 



Trifolium longipes Nutt. Scarce, in damp places near the Uma- 

 tilla. 

 Trifolium pratense L. Frequent in moist ground. 



