OF ARTS AND SCIENCES. 57 



species higher up the river valley, since it is not unlikely that 

 the two trees known were indigenous. The fact that there were 

 old houses and abandoned farms in the vicinity renders the 

 spontaneousness of the trees in some degree questionable. On 

 the other hand, the location of the trees with reference to the 

 houses was not such as to favor the supposition that they were 

 planted by the hand of man. 



23. Subularia aquatica L. 



In 1906, while hunting for shore plants at Lake Massabe- 

 sic, the compiler found a few plants of this very local crucifer 

 which had been driven by the south wind upon Severance's 

 beach, a long stretch of fine white "scouring sand" on the 

 north shore, in the town of Auburn. In October 1907, the lake 

 being unusually low, more of the bottom was exposed and the 

 plants were found in great abundance. In October 1908, when 

 the extraordinary drought of that season had still further re- 

 duced the level of the lake, so that the surface was 2 ft. below 

 the top of the dam at the outlet and 5 ft. below the level of the 

 lake when full, a much larger area of sand was exposed. There 

 was found (Oct. 8) to be an almost continuous belt of the 

 plants from 2 ft. to 2 rods wide, the greater part still immersed, 

 extending for a distance of not less than 1500 ft. A square foot 

 of sand, measured off where the plants were thickly sown, con- 

 tained by actual count more than 100 plants. 



[See also Rhodora, November 1908.] 



24:. Hudsoiiia ericoides L. 



There is an immense station of this species at Concord on 

 the high sand bluffs east of Merrimack river. The principal 

 station examined extends along the top and riverward slope of 

 the bluff for more than a quarter of a mile. There is more on 

 the next bluff northward, and still more south of the highway 

 8 



