— 6o — 
OGTODICERAS JULIANUM BRID. VAR. OHIOENSE, NEW VARIETY 1 
W. H. Emig 
Octodiceras Julianum Brid., a water moss of Fontinalis-like habit, is quite 
common attached to submerged boulders and rocks, in the rapids of Washita 
River where the river cuts through the Arbuckle Mountains of Oklahoma. Only 
a few plants of Octodiceras , much branched and four to six inches long, were 
found in the clear calcareous streams of this region. The water of the Washita 
River is clear for about two months during the late summer, but during the 
remainder of the year the water is muddy, more especially since the recent clear- 
ing of the local forests with its accompanying erosion of the exposed soil. Dur- 
ing the next few years this change in the turbidity of the river water may have 
a decided influence on the continued growth and habit of these plants. The 
moss stems, much branched and usually about two inches in length, occur in 
small compact clusters at the base of which the rhizoids are flattened into small 
discs that serve as holdfasts. The dark green, flexible, and submerged sprays 
of mosses appear from a distance like growths of the alga Cladophora. A 
minute examination of the moss soon reveals its identity. 
Specimens of this moss from Oklahoma were compared with a number of 
specimens, which had been determined as Octodiceras Julianum Brid., in the 
herbarium of the Carnegie Museum at Pittsburgh. In this collection there 
was one specimen — collected by Prof. L. S. Hopkins on August 20, 1909, in 
Portage County, Ohio — which, although sterile, was in certain respects different 
from the species. The more apparent differences of the new variety and the 
species are illustrated in figures 1, 2, and 3 of Plate XXVI. In the following table 
the several points of variation between the species and the new variety are 
indicated. 
Octodiceras Julianum Brid. 
Length of leaf 3-85-4.05 mm. 
Width of leaf at widest part 32 mm. 
Number of cells across widest part of leaf 
20-24 
Width of leaf above vaginant lamina .23 mm. 
Width of costa 02 mm. 
Diameter of average cell near 
the center of the leaf between 
margin and costa, rounded- 
hexagonal 012-.02 mm. 
Cells at base of leaf near midrib, 
rectangular 01X.02 mm. 
Length of vaginant lamina 1.35 mm. 
Costa ends below apex 16 mm. 
Along the midrib — Leaf cells are uniformly 
rounded hexagonal 
At margin Cells uniform with no in- 
dication of a margin 
var. Ohioense 
4 - 85 - 5-05 mm. 
.52 mm. 
30-36 
.39 mm. 
.02 mm. 
.016-.024 mm. 
.016X.03-.04 mm. 
1.80 mm. 
.16 mm. 
One or more rows 
of elongated rect- 
angular cells. 
Several rows of 
small cells that 
give the appear- 
ance of an indis- 
tinct margin. 
1 Contribution No. 2, Botanical Department of the University of Pittsburgh. 
