PHAEOPHYCEAE 



337 



Order Ectocarpales. . Zoospores and isogametes similar 

 and motile. 



Family 1. Ectocarpaceae. Mostly filamentous, sim- 

 ple or branched, with zoospores and 

 gametes. — ^Ectocarpus, Streblonema. 



Family 2. Myriotriehiaceae;3, Choristocarpaceae; 4, 

 Elachistaceae; 5, Chordariaceae; 6, 

 Stilophoraceae; 7, Spermatochnaceae; 

 8, Sporochnaceae; 9, Encoeliaceae; 10, 

 Desmarestiaceae; 11, Arthrocladia- 

 ceae; 12, Sphacelariaceae; 13, RaU- 

 siaceae; 14, Striariaceae; 15, Dictyo- 

 siphonaceae. 



Family 16. Laminariaceae. Large, parenchymatous, 

 usually stalked, with zoospores only. 

 — Laminaria, Alaria, Postelsia, Nereo- 

 cystis, Macrocystis. Egregia. 

 Order Cutleeiales. Zoospores and heterogametes dis- 

 similar and motile. 



Family 17. Cutleriaceae; 18, Splachnidiaceae. 

 Order Tilopteridales. Zoospores and heterogametes dis- 

 similar, eggs non-motile. 



Family 19. Tilopteridaceae. 

 Class 11. DICTYOTINEAE. Reproductive organs external, 

 heterogamic. (Sp. about 130.) 

 Order Dictyotales. Plants erect, flat, leaf-like. 



Family 20. Dictyotaceae. — Dictyota, Padina, Zonaria. 

 Class 12. CYCLOSPOREAE. Rockweeds. Reproductive or- 

 gans in sunken conceptacles, hetero- 

 gamic. (Sp. about 350.) 

 Order Fucales. Usually flattish, branched. 



Family 21. Durvillaeaceae. Conceptacles on vegetative 

 parts of plant. — DurviUaea. 



Family 22. Himanthaliaceae. Conceptacles on long 

 branches arising from a vegetative 

 cup. — Himanthalia. 



Family 23. Fucaeeae. Conceptacles on ends of vegeta- 

 tive branches. — Fucus, Ascophyllum. 



Family 24. Sargassaceae. Conceptacles on small 

 lateral branches. — Sargassum, Hali- 

 drys. 



