1 6 Charles E. Bcsscy 



Family 17. Cutleriaceae. Plants medium to large, flat, 

 branched or orbicular, attached by rhizoids, Cutleria, Zanardinia. 

 (Pf. I, 2, 262.) 



Order Tilopteridales (Acinetae). Reproductive cells un- 

 like; zoospores medium sized, biciliated; sperms small, biciliated; 

 eggs large, non-ciliated. 



Family 18. Tilopteridaceae. Plants consisting of tufted, more 

 or less branched, filaments attached below by rhizoids. Tilopteris. 

 (Pf. I, 2, 265.) 



Class ID. TETRASPOREAE. Reproductive organs external 

 on the surface, or on special plants; propagation by tetraspores 

 (non-ciliated) ; generation by non-ciliated heterogametes. 



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

 attached below by rhizoids. 



Family 19. Dictyotaceae, With the characters of the order. 

 Zonaria, Padina, Dictyota. (Pf. I, 2, 291.) 



Class II. CYCLOSPOREAE. Reproductive organs sunken 

 in "conceptacles" ; propagation by simple fragmentation, no zoo- 

 spores ; sperms small, biciliated ; eggs large, non-ciliated. 



Order Fucales. Plants from medium to large, usually flattish, 

 branched, attached below by rhizoifls. 



Family 20. Durvillaeaceae. Conceptacles on the vegetative 

 portions of the plant, no dift'erentiation of reproductive and vege- 

 tative branches. Diirvillaca, S planchnidinm. (Pf. I, 2, 268, 278, 

 279, 289.) 



Family 21. Himanthaliaceae. Conceptacles on long, dichoto- 

 mous fertile branches which spring from a cup-shaped vegetative 

 base; oogones one-spored. Hiinanthalia. (Pf. I, 2, 268, 278, 

 279.) 



Family 22. Fucaceae. Conceptacles on the specialized ends of 

 the vegetative branches, sometimes on the whole plant ; oogones 

 with two to eight spores. Myriodesma^ Fucus, Ascophyllum. 

 (Pf. I, 2, 268.) 



Family 23. Sargassaceae. Conceptacles on small lateral 

 branches ; oogones one-spored. Sargassuin, Halidrys, Cystnscira. 

 (Pf. I, 2, 268, 279, 281.) 



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