1923] Knowlton,—Butomus umbellatus on St. Lawrence River 221 
Butomaceae, closely related to the Alismaceae, but distinct because of 
its nine stamens, six separate carpels, and the lack of placentae, as 
the ovules are borne all over the interior walls of the carpels. It is a 
marsh plant widely distributed in Europe and western Asia, commonly 
known as the flowering rush. 
This species was first found on the St. Lawrence by Brothers 
Marie-Victorin and Rolland-Germain in 1905, at Laprairie on the 
flats (battures) of the river. It was soon after discovered at Beau- 
harnois, Chateaugay, Valois and Longueuil, and was first reported in 
Le Naturaliste Canadien of May, 1908, and The Ottawa Naturalist 
of July, 1908. An independent appearance of the plant along the 
canal at Ottawa as early as 1906 was reported by E. H. Blackader 
in The Ottawa Naturalist of December, 1908. 
By 1918 the plant had spread so fast that Brother Marie-Victorin 
wrote as follows:! “One of the latest floral acquisitions—a desirable 
one—made on the shores of the St. Lawrence, is the flowering rush, 
the umbellate Butomus, a very pretty plant which covers broad flats 
at least from Chateaugay to Nicolet, and which is especially abundant 
about Montreal. This beautiful Alismaceous species spreads rapidly, 
as is shown by its conquest of this large domain in less than forty 
years. It has not been reported elsewhere in America." 
In our own travels the past summer we found Butomus at Ste. 
Angéle de Laval, Pointe du Lac, Berthierville, St. Sulpice and St. 
Lambert. In the Gray Herbarium is a specimen from the wet 
stony beach at Lachine, collected in 1922 by Judge J. R. Churchill, 
and another from the “zone intercotidale de la grève de Beauport” 
(near Quebec) collected by Brother Rolland in 1922. The flowering 
rush is evidently spreading rapidly down river. As it has many 
seeds, it would seem quite possible for it to work gradually up the 
St. Lawrence and its tributaries, so that some day it may make its 
appearance by Lake Ontario or Lake Champlain, within the limits 
of the United States. 
A good description of the genus and species can be found in the 
North American Flora, Vol. 17, pt. 1. 63, 1909. 
HiNGHAM, MASSACHUSETTS. 
1 Revue Trimestrielle Canadienne, 263, November, 1918. 
Vol. 25, no. 299, including pages 189 ic 204 was issued 4 December, 1923. 
