1010 



COMPOSITAE 



Lactuca 



50 



Map 2217 

 Lactuca Scanola 

 van integrata Gren & Godr. 



Leaves irregularly pinnatifid, segments 3-12 7. L. spicata. 



Leaves not divided or the lower ones sinuate 7a. L. spicata var. integrifolia. 



1. Lactuca Scariola L. Prickly Lettuce. Map 2216. Frequent to 

 abundant throughout the state. It seems to be periodic in its abundance. 

 Some years it is rarely seen and other years it is a common weed. It is 

 found along roadsides and railroads, in waste places in general, and in 

 fallow and cultivated fields. It is usually found in greatest abundance in 

 wheatfields and oatfields. It seems that it appeared in Indiana about 1890, 

 and in a few years it had become an obnoxious weed throughout the state. 



Nat. of Eu. ; N. E. to Ga. and Tenn., westw. to Calif. 



la. Lactuca Scariola var. integrata Gren. & Godr. Map 2217. I 

 can not separate this form of the prickly lettuce from the preceding one 

 in reports, so I must rely upon the data of the specimens at hand. It has 

 the same habitat as the species and I believe that it is rather infrequent 

 in the state. 



Nat. of Eu. ; probably local throughout the greater part of the U. S. 

 I have a specimen from N. Mex., and Jepson reports it from Calif. 



2. Lactuca campestris Greene. (Pittonia 4: 37-38. 1899.) Map 2218. 

 I found two plants of this species in the old lake basin of Beaver Lake 

 about 200 feet west of the bridge on U. S. Highway 41 over the Beaver 

 Lake ditch about 3 miles south of Lake Village. It was growing in dry, 

 sandy soil near the ditch. Evidently it is scarce in this area because a 

 companion and I searched for several hours for more of it. The two 

 plants were about 100 feet apart on opposite sides of the ditch. This 

 species is conspicuously different from all others of the genus because of 

 its leafy and short stem, and its broad rather naked inflorescence, which 

 is well above the leaves. 



It was described from specimens collected in southwestern Minnesota 

 and is a western plains and prairie plant. Its distribution is not known 

 because most authors do not separate it from Lactuca ludoviciana which 

 has yellow flowers. 



