158 
OPEN LETTERS. 
Mentzelia affinis as a field weed. 
I send by to-day’s mail a plant (Mentzelia, I think) which 
bids fair to become the worst weed ever known here. It 
made its first appearance in 1889; but scarcely a dozen 
plants were then observed in all the region. This year it 
has choked out and ruined the wheat crop in some places. 
What is it? Where does it come from? Is it elsewhere 
known as the terrible pest which it threatens to become in 
our section?—W. A. Sanpers, Sanders, Calif. 
[The specimen sent is not only a Mentzelia, but represents 
a species of southern California which has not long been 
own to botanists, namely, M. affinis, Greene. Mr. 
Sanders’ specimen measures full three feet in height; a 
size considerably exceeding that which I had attributed to 
the plant when publishing its character. It is not the only 
instance in which ‘a native plant, finding the grain fields 
congenial ground, has become a troublesome weed.—E. L. a. | 
Botanical excursion to Mount Gavilan. 
I have recently made an excursion of one day to Mt. 
Gavilan, or Fremont’s Peak. The field is not a rich one; 
and botanically the trip was rather disappointing. 
Mt. Gavilan is a ridge about three miles in length, running 
due east and west, and quite distinct from that section of 
the Coast Range called the Santa Cruz Mountains. The 
ridge is surmounted by a series of peaks of igneous rock. 
The most easterly peak is the highest. The region is 
almost bare of trees and bushes, except as to the spurs and 
cafions at the base of the range. It has long been severely 
pastured down by cattle, even to the very summit of the 
peak. LErodium, and certain common barnyard weeds were, 
however, quite abundant. Ranunculus, dodecatheons and 
violets were the prevailing flowers. The northward slope of 
the ridge is more abrupt; and on this side of some of the peaks 
