166 Vnivcrsity of CalifoniUi l'ublicatio)is in Botany [Vol.8 



Solier, Mem. sur deux Algues, 1847. p. 162, pi. 9, f. 18-30; Collins, 

 Green Alg. N. A., 1909, p. 407. Bryopsis Balhismna var. Lamouroiixii 

 J. Agardli, Al<r. Med., 1842, p. 18. 



Tliis species is represented in the Herbarium of the University 

 of California by two sterile specimens collected by ]\Irs. E. A. Law- 

 rence, five miles south of the boundary between southern and Lower 

 California. It is decidedly coarser than any other of the described 

 species of the genus. 



FAMILY 6. CODIACEAE (trevis.) z^vnard. 



Thallus dark green, spongy, subspherical, applanate or erect, 

 cylindrical, flattened, or jointed, simple or dichotomously branched, 

 at times incrusted with lime, composed of intertwined branching fila- 

 ments, the peripheral branchlets forming a palisade or pavement-like 

 external layer; septa (diaphragms) frequent but in connection with 

 formation of reproductive organs or in older filaments ; chloroplasts 

 parietal, small, very numerous, especially at the apices of the branches, 

 destitute of pyrenoids; multiplication through fragmentation and by 

 zoospores and anisoplanogametes ; zoosporangia and gametangia differ- 

 entiated and variously situated. 



Zanardini, Sagg. di class, nat. d. Ficee., 1843 (table opposite p. 17). 

 Codieae Trevisan, Prosp. fl. Eugan., 1842, p. 50, Flora, 1843, p. 465 

 (in part). 



The family, originally separated as Spongodiees by Lamouroux 

 (1813, p. 280 or p. 71 of repr.), has long been recognized as distinct 

 among the Chlorophyceae. It contains the most highly differentiated 

 of the genera of the marine Green Algae, both as to complexity of 

 thallus and as to differentiation of the reproductive cells, its only 

 competitors being the Dasycladaceae and the Vaucheriaceae. The 

 thallus is made up of interwoven coenocytic filaments, the peripheral 

 branchlets of which are distinctly and variously differentiated and 

 combined into a distinct external layer. The sporangia and game- 

 tangia are formed from modified lateral branchlets of the coenocytic 

 filaments and the gametes are distinctly unlike in some species at 

 least. Many of the species are heavily incrusted with lime and are 

 important agents in the building up of coral reefs. The majority of 

 the species are strictly tropical but some of the species of C odium are 

 to l)e found in subtropical, temperate, and perhaps even in frigid 



waters. 



Key to the Genera 



1. Thallus without joints or calcification 7. Codium (j). 167) 



1. Thallus with distinct joints and more or less calcified 8. Halimeda (p. 17G) 



