FRESH-WATER ALGJE OP THE UNITED STATES. 221 



portions of the fronds, however, the glomeruli are more fasciculate and more 

 distinct, for although sometimes so close as to be almost confluent at their spread- 

 ing edges, at their bases they are distinct. This species very probably attains a 

 much larger size than indicated by my specimens, and possibly varies as much in 

 color as B. moniliforme. 



Genus TUOMEYA, Haevet. 



" Frond cartilaginous, continuous, solid, at first transversely banded, afterwards annularly con- 

 stricted ; composed of a longitudinal axis, and two strata of peripheric cells. Axis columnar, 

 consisting of several longitudinal cohering filaments, beset with closely placed whorls of moniliform 

 ramelli, whose branches anastomose horizontally and vertically into a cellular peripheric membrane, 

 which is coated externally with moniliform filaments, gradually developed. Fructification probably 

 in the superficial filaments. 



T. fluviatilis, Harvey. 



Sab. — On stones, in rivers and streams. River in Alabama ; Prof. Tuomey. Near Fred- 

 ericksburg, Virginia; Prof. Bailey. 



Fronds tufted, an inch or two in height, scarcely as thick as a hog's bristle, much and irregu- 

 larly branched, bushy ; the branches alternate or secund, scattered or crowded, twice or 

 thrice divided, and set with scattered patent ramuli which are slightly constricted at the in- 

 terstices, and taper to an obtuse point. When young the branches and raninli are perfectly 

 cylindrical, and when examined under a low power of the microscope show a surface com- 

 posed of minute, dotlike cells, placed close together, and marked at short intervals with dark- 

 colored 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 specimens the branches and ramuli are annularly constricted at short 

 intervals, the nodes becoming swollen, whilst 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 excnrrent 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 peri- 

 phery 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 

 colored, and I consider them to be connected with fructification. The color is a dark olive. 

 The substance is brittle, rigid when dry, and the plant scarcely adheres to the paper. The 

 generic name is in memory of the late Prof. Tuomey, of Tuscaloosa." 



Bemar7cs.—1 have no knowledge of this plant, and have simply copied the de- 

 scription of Prof Harvey J Smithsonian Contributions, 1846. 



Family LBMANEACE^. 



Algffl rivnlares vel fluviatiles. Thallus e proembryone confervacea enascens, setaceus, subsimplice 

 vel fasciculatim ramosus, cavus, nodosus, e cellularum stratis internis et corticatis formatus, Noduli 

 plerumque papillarum corona instructi. Polysporae numeros®, in seriebus ramosis moniliformibns 

 fasciculatim aggregatse, sine fecundatione germinantes. 



