FRESH-WATER ALG.E OF THE UNITED STATES. 213 



able to identify them. One of tlie forms grows in this immediate locality, and is very 

 probably C. sciitdfa, Brel). The other was collected in Northern Michigan. It is 

 characterized by its frond never being disciform, although composed of a single 

 plane of cells parenchematously united. 



Class RIIODOPHYCE^. 



AlgfB multicelliilares, vegetatione teruiinalis noii limitata pra3dita3 

 plenimque trioica^. 



Tliallus e cellularum seriebus vel stratis singulis vel pluribus compo- 

 situs, aut nudus aut e cellularum stiato corticatus, forma quam maxime 

 varius; membranaceus (Porpliyridium), crustaceus (Ilildenbrandtia), 

 filamentosus et verticillatim ramosus (Batrachospermum, Thorca), fascii- 

 formis (Bangia), foliaceus, etc. 



Cytioplasma plerumque rhodophyllo (Cohn), rarius phycho-chromate 

 coloratum, granula amyloidea vel amylacea et sa3pe guttulas oleosas 

 includens. 



Propagationis organa triplicis indolis, saepissime in plantas distinctas 

 disposita. 



1. Orr/ana onascvla vel anfJwri'da e fasciculis cellurarum plerumque mo- 

 niliformibus ramosis, denique in spermatozoidea vel spermatia fcecun- 

 dantia {Sporidia I. Ag.) oblonga vel ovalia, achrod, immobilia dissolutis 

 formata. 



2. Organa fcminea vel cysfocarjna Ktz. e soris nonnunquam monilifor- 

 mibus formata, qui e placenta saepissime corticali evolvuntur, nudi vel 

 cuticula mucilaginosa vel involucro inclusi, denique sporas [polijsporas) 

 numerosas immobiles mox germinantes emittunt. Foecundatur cysto- 

 carpiinn statu primordial! ope organi piliformis [trlcliogijne Thuret et 

 Bornet) quorum spermatia copulantur. 



3. Tctrasporangia e cellula corticali unica valde intumescente formata, 

 divisione utriculi primordialis cruciata quadrilocularia; in quoque loculo 

 {ceUulis secundariis, soroi'iis) spora unica {tctrasporxi) se format, quae sine 

 foecundatione germinat. (R.) 



Multicellular alga% mostly tritecious, furnished with unlimited not ter- 

 minal vegetation. 



Thallus composed of cells in rows or in a simple or multiple stratum, 

 either bare or provided with cortical strata of cells, exceedingly various 

 in form; membianaceous (Pophyridium), crustaceous (Hildenbrandtia), 

 iilamentous and verticillately branched (Batrachospermum, Thorca), 

 fasciate (Bangia), foliaceous, &c. 



Cytioplasm mostly rhodophyllous, rarely phycochromatously colored, 

 including amyloid granules or starch and frecpiently oil drops. 



Propagation by means of three immotile organs, generally placed 

 upon distinct plants. 



1. Antlieridia composed of mostly moniliformly branched fascicles of 



