PHAEOPHYCEAE . 337 
Order EcrocaRPALES. Zoospores and isogametes similar 
and motile. 
Family 1. Ectocarpaceae. Mostly filamentous, sim- 
ple or branched, with zoospores and 
gametes.—Ectocarpus, Streblonema. 
Family 2. Myriotrichiaceae; 3, Choristocarpaceae; 4, 
Elachistaceae; 5, Chordariaceae; 6, 
Stilophoraceae; 7, Spermatochnaceae; 
8, Sporochnaceae; 9, Encoeliaceae; 10, 
Desmarestiaceae; 11, Arthrocladia- 
ceae; 12, Sphacelariaceae; 13, Ralf- 
siaceae; 14, Striariaceae; 15, Dictyo- 
siphonaceae. 
Family 16. Laminariaceae. Large, parenchymatous, 
usually stalked, with zoospores only. 
—Laminaria, Alaria, Postelsia, Nereo- 
cystis, Macrocystis. Egregia. 
Order CuTLERIALES. Zoospores and heterogametes dis- 
similar and motile. 
Family 17. Cutleriaceae; 18, Splachnidiaceae. 
Order TILoPpTERIDALES. Zoospores and heterogametes dis- 
similar, eggs non-motile. 
Family 19. Tilopteridaceae. 
Class 11. DICTYOTINEAE. Reproductive organs external, 
heterogamic. (Sp. about 130.) 
Order Dicryorates. 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 Fucates. Usually flattish, branched. 
Family 21. Durvillaeaceae. Conceptacles on vegetative 
parts of plant.—Durvillaea. 
Family 22. Himanthaliaceae. Conceptacles on long 
branches arising from a vegetative 
cup.—Himanthalia. 
Family 23. Fucaceae. Conceptacles on ends of vegeta- 
tive branches.—Fucus, Ascophyllum. 
Family 24. Sargassaceae. Conceptacles on small 
lateral branches.—Sargassum, Hali- 
drys. 
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