1 8 Charles E. Bessey 



Order N em align ales. The fertilized oogoiie gives rise di- 

 rectly to the erect or more or less spreading, tufted sporophores 

 ("gonimoblasts"), which are naked, or enclosed in a protective 

 envelope. 



Family 4. Lemaneaceae. Plants consisting of delicate branch- 

 ing threads, living in freshwater. Lcmanea. (Pf. I, 2, 324.) 



Family 5. Helminthocladiaceae. Plants filamentous, simple or 

 parenchymatous, variously branched, usually slimy and some- 

 times encrusted with lime ; mostly marine. Batrachospermiim 

 (in fresh water), Ncmalion, Liagora. (Pf. I, 2, 327.) 



Family 6. Thoreaceae. Plants erect, filamentous, simple or 

 branched, covered with parallel hairs, living in fresh water. 

 Thorca is the only genus. (Pf. I, 2, 321.) 



Family 7. Chaetangiaceae. Plants varying from dichoto- 

 mously branching, rounded stems to more or less flattened, m.as- 

 sive, leaf-like structures; all marine. Chaetangium. (Pf. I. 2, 



325-) 



Family 8. Gelidiaceae. Plants ranging from minute epiphytes 



to slender and gracefully branched forms, and stout branched 



parenchymatous masses, all marine, and a few species (of Chore- 



ocolax) parasitic and colorless. ' Wrangelia, Gclidiiim. (Pf. I, 



2, 340.) 



Order Gigartinales. The fertilized oogone conjugates with 

 its nearby auxiliary cell; the latter then gives rise to the sporo- 

 phores, which branch copiously in the surrounding tissue of the 

 plant body. 



Family 9. Acrotylaceae. Plants parenchymatous, erect, 

 branching, flattish; tetraspores zonate. Acrotyhis. (Pf. I, 2, 



350.) 



Family 10. Gigartinaceae. Plants parenchymatous, erect or 

 spreading, branching, cylindrical, flattened, or leaf-like ; tetras- 

 pores cruciate. Chondrus, Iridaea, Gigartina, Callophyllis, Cal- 

 lymenia. (Pf. I, 2, 352.) 



Family 11. Rhodophyllidaceae. Plants parenchymatous, erect 

 or spreading, branching, flattened, or less commonly leaf-like; 

 tetraspores zonate. Rhodophyllis, Rhabdonia. (Pf. I, 2, 366.) 



Order Rhodymeniales. The fertilized oogone conjugates with 



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