662 University of California Puhlications in Botany [Vol. 8 



the frond with a slight tendency to concentric zonation; antheridia 

 unknown ; oogonia 140-200jli long, 70-90/x broad, wall 10-12/x thick ; 

 aplanosporangia about the same size, but with much thinner walls. 



Growing in the lower littoral and upper sublittoral belts. Widely 

 distributed in the Gulf of California, and as far north as Magdalena 

 Bay, Lower California. 



Bory, Diet, class, hist, nat., vol. 12, 1827, p. 591 ; Voy. Coquille, 

 Bot. Crypt., 1828, p. 147, Atlas, 1826, pi. 21, tig. 1 ; Howe, Phyc. Stud. 

 V, 1911, p. 497; Setchell and Gardner, Mar. Alg. Gulf Calif., 1924, 

 p. 729. 



There may be other species represented on our coast, but all of the 

 specimens in our hands seem to belong to the same coarse, thick, dark 

 colored species which passes under the foregoing name. 



Series 3. CYCLOSPOEEAE aresch. 



Thallus at maturity never unicellular nor monosiphonous, simple 

 or branched, varying in size from a few centimeters to several meters 

 long, usually saxicolous but rarely epiphytic or floating, composed of 

 highly differentiated and complex tissues, always solid, provided in 

 part with specialized cavities, the vesicles, tilled with gas which serves 

 to buoy the plant; multiplication in a few (e.g., Sargassum) by frag- 

 mentation ; growth terminal ; reproduction sexual only, the oogonia, or 

 unilocular female gametangia, and antheridia, or unilocular male 

 gametangia, being located within the thallus, or frond, in specially 

 developed cavities (the conceptacles) scattered over the whole .surface 

 of the frond or limited to specialized terminal or subterminal parts 

 (the receptacles) ; the female gametes non-motile, the male gametes 

 motile- by two laterally placed cilia of unequal length and possessing a 

 small, red ' ' eye spot ' ' ; fertilization is effected after both gametes have 

 escaped into the water ; branched paraphyses associated with the 

 reproductive organs and often extruding through the osteole of the 

 coneeptacle. 



Areschoug, Phyc. Scand., 1846, p. 28 Repr. 



The members which now constitute this series are diverse and 

 heterogeneous, both as to structure and form. Scarcely any two 

 authors have agreed from the beginning up to the present time as to 

 their grouping into orders, families, etc. The various genera, now 

 regularly assigned to the series, are, in general, in close agreement 

 regarding the method of reproduction. The gametangia (oogonia 

 and antheridia) are both unilocular and are borne on the same or on 



