426 BOTANICAL GAZETTE [ DECEMBER 
Thorea is widely distributed over the world, having been reported 
from France, Germany, England, Denmark, Austria, Venezuela, Ecua- 
dor, Java, and the Marianne islands. In Ecuador it is said to be espe- 
cially abundant. 
Our description of the Nebraska plant does not differ essentially 
from that of Schmidle in his excellent monograph of Zhorea ramosis- 
sima Bory In our plant the body consists of long cylindrical 
branches, originating near the base, and these again have occasional 
branches. The color is an olive green, rather than the black or brown 
color mentioned by Schmidle. When dried, the plant retains its olive 
green color, becoming somewhat brownish. ‘The whole plant is about 
5°" long, and 2 to 3™ wide, when floating in the water. Each branch 
consists of two distinct portions, viz., an outer covering of several- 
celled hairs or ramelli, and a denser axial portion of interlacing 
cellular filaments, which are held more firmly together by a mucilagi- 
nous matrix which sheaths every fiber and extends outwards as far as 
the first two or three basal cells of the hairs. The surrounding zone of 
hairs. has a width of from 400 to 6oop, being of nearly the same 
diameter upon all portions of the plant body, except at the base. 
The axial portion has a varying diameter, ranging from 700p at the 
base to less than 1oop at the growing point of the branch. 
The hairs grow at right angles to the axis and constitute two quite 
distinct belts; an outer belt of quite evenly distributed long hairs, 
having an average length of soom; and an inner belt of clustered, 
short hairs of an average length of 70 to gow. The long and short 
hairs are intermingled, and both kinds spring from the same basal 
cell. The short hairs are protected by gelatinous sheaths, which 
are extensions of the central gelatinous matrix. The cells of the long 
hairs are rectangular in shape, and quite uniform in diameter. The 
short hairs have shorter cells, which are also nearly uniform in diam- 
eter, yet in some cases they taper slightly towards the apex. In the 
older portions of the branches the short hairs are more numerous, 
while in the younger region the long hairs predominate. As the plant 
matures, the apical cell of the short hairs often develops into an 
asexual spore (aplanospore). Among the short hairs, and often from 
the same basal cells, there may arise narrow hairs which develop 4 
small cluster Of similar asexual spores, rarely over five in number. 
SSCHMIDLE: Untersuchungen iiber Zhorea ramosissima Bory. Hedwigia 
35 :1-33. 1896. 
