BATRACHOSPERMEJ:. 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, scai'cely 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 togethec, 

 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, the 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 fuviatilis ;" but, as may be gathered from 

 the above description, it is very dilFerent from Lemanea in structure and much more 

 nearly related to Batra^hospermum. 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. 



