208 AMERICAN MIDLAND NATURALIST. 
margined on one or both sides, 2.5 cm. long, 1 mm. broad, 
ovoid, all covered by the subtending bract. 
e predominant feature of this species is its peculiar as- 
pect, the stem being simple throughout to the top with its 
short peduncled spikes in the upper axils. Its nearest relative, 
C. nitidum Kit., is bushy-branched throughout; its leaves are 
narrowly linear and seldom more than 2 cm. long; its bracts 
are not imbricated and are narrower than the utricle, which is 
2 mm. long and 1 mm. wide and winged, and the plant is al- 
most glabrous. 
C. hyssopifolium L. is profusely branched throughout, its 
leaves up to 6 cm. long and 4 mm. wide: its bracts are im- 
bricated and its utricle is 3.5-5 mm. long, winged 
No. 112 in my private herbarium. The plant was collected by 
me Aug. 26, 1890, on the shore of a lake several miles south- 
cality from which it is known to me. 
Leeds, North Dakota. 
The Laboratory Aquarium.* 
J. A. NIEUWLAND. 
The term aquarium in its broadest sense may be said to 
 *Paper read at the meeting of the Indiana Science and Mathematics 
Teachers, Richmond, Ind., March 5, 1910. 
