BATRACHOSPERMEaE. 
65 
Hab. On stones, in rivers and streams. River in Alabama, Prof. Tuomey. Near 
Fredericksburg, Virginia, Prof. Bailey, (v. s. in Herb. T.C.D.) 
Fronds tufted, an inch or two in height, scarcely as thick as hog’s bristle, much and 
irregularly branched, bushy ; the branches alternate or secund, scattered or crowded, 
twice or thrice divided, and set with scattered, patent ramuli, which are slightly con- 
stricted at the insertions, and taper to an obtuse point. When young the branches 
and ramuli are perfectly cylindrical, and when examined under a low power of the 
microscope show a surface composed of minute, dotlike cells, placed close together, 
and marked at short intervals with dark coloured transverse bands. These bands 
disappear under a higher magnifying power. They are indications of the nodes of the 
axis of the frond, seen through the peripheric stratum. In old, fully developed speci- 
mens the branches and ramuli are annularly constricted at short intervals, th.e nodes 
becoming swollen, while the internodes remain unchanged. When a young branch is 
bruised between two pieces of glass the axis may be readily extracted. It consists of 
several parallel, longitudinal, jointed threads combined together at closely placed nodes , 
from which issue horizontal dichotomous filaments composed of roundish or angular 
cells. These excurrent filaments spread both horizontally and vertically, and their 
branches anastomose into a cellular mass or fleshy membrane which forms the inner 
peripheric stratum. In young plants a portion of the frond, between the axis and 
periphery, is hollow, but in older ones the cavity is quite filled up with cells. The 
external surface of the cellular periphery is clothed with a coat of moniliform filaments 
gradually developed, and forms what is above called the second peripheric stratum. 
These are found only in fully grown specimens ; they consist of much smaller cells 
than those of the inner stratum ; they are more strongly coloured, and I consider them 
to be connected with fructification. The colour is a dark olive. The substance is 
brittle and rigid when dry ; and the plant scarcely adheres to paper. 
I formerly received specimens of this curious little plant from my late friend 
Prof. Bailey, under the name “ Lemanea fluviatilis but, as may be gathered from 
the above description, it is very different from Lemanea in structure and much more 
nearly related to Batrachospermum. The external habit, substance, and colour are 
however those of a Lemanea , and without microscopic examination it might pass for 
one. The structure is difficult to see and also to describe in words. What I have called 
the inner peripheric stratum is externally as solid as the walls of a Lemanea ; the outer 
periphery consists in a continuous clothing of the external surface of the frond with 
minute, fastigiate, horizontal ramelli, not unlike those of which the globose fructifi- 
cations of a Batrachospermum are made up. In young specimens only can the mode 
of evolution of the frond be observed ; old specimens become completely blocked up 
with cellular tissue, and seem to be solid in every part when a transverse slice is 
examined ; their axis may, however, be seen by employing a compressing glass. 
The generic name is bestowed in memory of the late Prof. Tuomey of Tuscalosa, 
Alabama, so often mentioned as a valuable contributor to these pages. I have not 
ventured to make a drawing from the dried specimens which alone I have yet seen. 
K 
