58 FRESH-WATER ALGJE OF THE UNITED STATES. 



Var. KERATOPHYTUM, Bory. 



Separated from the typical plant mainly in having the 

 whorls distinct. Plate LXIV, fig. 1, is the natural size. Fig. 

 2, a branched end of a filament moderately magnified ; fig. 3, 

 two whorls of the last more highly enlarged. 



This variety occurs frequently in lakes and streamlets of 

 New Jersey, often six to eight inches long. 



Genus 5, THOBEA, Bory. 



Thallus filarnentose, attenuated at the apex, branched, light 

 purple or purple-brown, villose, mucose, with a solid cen- 

 tral medullary stratum, surrounded by dichotomously divided 

 branchlets. 



THOREA RAMOSISSIMA, Bory. 



From a hand's-breadth to a foot long, and rarely two feet 

 long, very much branched ; about the thickness of a horse- 

 hair, dark green or when dried of a beautiful purple- violet, 

 ramuli spreading horizontally, long and short alternating, 

 articulate; joints 1-3 times as long as broad, or twice that 

 length. 



Syn. Batrachospermum Mspidum, De Cand. 



Found a mere fragment of a frond in lake at Winter Park, 

 Florida ; enough to identify the plant, but not sufficient for 

 the above description ; have taken it from Cooke's British 

 Fresh- Water Algse, p. 293. 



Plate LXXI, fig. 1, natural size. Figs. 2, 3, fragments of 

 filaments magnified. Figs. 4, 5, base of ramuli greatly 

 enlarged. 



Genus 6, CHANTBANSIA, Fr. 



Found in small caespitose clusters or tufts, steel blue or pur- 

 plish violet, of much more simple structure than Batraclwsper- 

 mum. Filaments articulate, formed of a single series of cylindrical 

 cells, branched ; branches simple or compound, not verticil- 

 late, naked. Carpospores in small clusters on the ends of short 

 branchlets. 



Sexual propagation takes place, according to Sirodot, by car- 

 pogons attached to lateral branches, fertilized by means of tricho- 

 gynes. Asexual multiplication by means of tetraspores devel- 

 oped on the end of cells, in appearance similar to carpospores. 



