1899] BRIEFER ARTICLES 425 
the same species. Koch states in the older edition of his Flora 
that Linnzeus included several forms in P. domestica, which rightfully 
belonged to PP. insititia. Even this question has to be settled in 
Europe. 
As to the non-existence of P. ¢nsititia in America, I agree fully 
with Professor Waugh, for the following reasons: If Dr. Gray had 
had what is known as FP. insititia in Sweden, I doubt that he would 
have made it a variety of P. spinosa. Dr. Gray’s statement that it is 
“adventitious in hedgerows” made me very suspicious when I saw it 
in his manual a year or two ago; for P. inszti#ia, so far as 1 know, is 
never used for hedges. I think that P. msifitia should be erased from 
the list of American plants.—P. A. RypBerc, Wew York Botanical 
Garden. 
NOTES ON THOREA. 
(WITH PLATE XXVI) 
On October 1, 1898, Mr. A. A. Hunter, collector for the botanical 
department of the University of Nebraska, found specimens of Zhorea 
ramosissima Bory in Rock creek, a small stream near Lincoln, Neb.’ 
The plants were floating from a gravelly bottom in swift running 
water at a depth of half a meter and were surrounded by a mass of 
other algee, principally Vaucheria. Subsequent search for Thorea in 
this locality has thus far proved unavailing. 
So far as we know, Thorea has been found toa certainty ay but 
three other localities in North America. E. Hall collected a specimen 
of Thorea ramosissima Bory in the Sangamon river, Illinois, in 1866, 
and this, with specimens of other fresh water alge, was afterwards sent 
to the Botanical Museum of Berlin, where it is still preserved.” 
Francis Wolle found a mere fragment of Thorea in a lake at wintes 
Park, F lorida, date not given.’ Professor De Alton Saunders,’ in 
December 1898, found Thorea in abundance in running water from 
springs in Texas, the stations being San Marcos (Hayes county ee 
Braunfels (Comal county), and San Antonio (Bexar county). 
*See notice in Bor. Gaz. 27:71. 1899. 
Us: Thorea ramosissima Bory bei Belgrad in Serbien un 
- Hedwigia 38:114. 1899. 
*WOLLE: Fresh water algze of the United States, 58. 1887. 
n formalin. 
d denen weitere 
- ®Macn 
Verbreitung 
‘Communicated in a letter, accompanied by specimens ! 
