302 Naturalized Plants. [zoe 



indigenous in Northern Mexico, of which physiographic province 

 our desert region is an extension, so that there appears to be no 

 good reason for refusing to consider it as native on this side the 

 line. This is also indicated by the places in which it grows on the 

 Colorado desert. Very few exotic plants have established them- 

 selves in that arid region, and these are not often met with away 



(^d 



But Oligomeris is not 



found in these places so much as in remote and unfrequented canons, 

 where the chances of its introduction are at the minimum. It is 

 not an abundant plant in this State, and its Californian range was 

 long ago accurately indicated by Torrey, as " dry places between 

 the Colorado and the sea coast."* The most northern station on 

 the mainland, known to me, is at Santa Monica, where it has been 

 collected by Dr. Hasse. 



On the islands it has been reported usually as abundant, from 

 Magdalena to the Channel Islands off Santa Barbara. f Mr. Bran- 

 degee also reports it as occurring throughout the whole of that large 

 part of the Peninsula which he has recently explored. Its presence 

 through this arid and desolate region renders it still more difficult 

 to consider it an introduced species. 



Petimia parviflora has a generally similar geographical range, 

 being found on both sides of the boundary from the Gulf of Mexico 



X 



sea shore as 



far north as Monterey.§ It has not been reported from any of the 

 coast islands, nor from the peninsula of Lower California. It Has 

 been usually considered a native, but a shade of doubt has been 

 thrown upon it by Dr. Gray, who calls it " a naturalized weed, and 

 perhaps mdigenous along the southern borders of the United 



States.' ' 



1 



the native plants, so that tliere may be said to be no dissent to this 



* Pac. R. R. Rep., v, 359. 



tMagdalena, Rrandegec, PI. Baj. CaL, 129; Cedros, Greene. Pitt., i. 200; Guada- 

 lupe, Paln,er, Proc. Am. Acad., xi, 113; SantaCatalina and San Clemente. Lyon, 

 Bo . Gaz X,, 333-4; ban Miguel. Greene, 1. c., 86; Santa Cru... Greene, Bull. 



tTorr. Mex, Bound., 155. 

 {Dot. Cal., i, 546. 



llSyn. FI., II, i, 243, fib., Supp., 468. 



