1920] Setchell-Gordiier: Chlorophyceae 167 



7. Codium Stackh. 



- Thallus spongy, not incrustcd with lime, applanate, subspherieal 

 or cylindrical, simple or dicliotoniously branched, attached, dark 

 green; medullary filaments vertically intertwined, giving rise to hori- 

 zontal branchlets whose tips, swollen into "utricles," form a con- 

 tinuous external palisade layer; multiplication by frag'mentation of 

 the thallus; sexual reproduction through 2-ciliated anisogametes pro- 

 duced in gametangia situated laterally on tlu" utricles; dio(>eious or 

 occasionally monoecious. 



Stackhouse, Nereis Brit., 1797, p. xvi. Lamarckki Olivi, ('/( Olivi, 

 Zool. Adriat., 1792, p. 258, and in Usteri, Ann., part 7, 1794, p. 76. 

 Spongodium Lamouroux, Essai, 1813, (p. 72 repr.). 



The designation of this genus presents certain difficulties. The 

 earliest name proposed seems undoubtedly to be Lamarckia of Olivi 

 (1792, p. 258 and 1794, p. 76). There are, however, several other 

 genera dedicated to Lamarck and the generic names have been spelled 

 in various ways. The first of these was proposed by Medicus in 1789 

 (p. 28), but is now regarded as a synonym of the Malvaceous genus 

 Sida. Lamarkia of Monch, proposed in 1794 (p. 201) is still recog- 

 nized as a genus of grasses, and has been adopted by the International 

 Botanical Congress at Vienna as a nomen conservandum (cf. Briquet, 

 1906, p. 73, and 1912, p. 79). Codium was proposed by Stackhouse 

 in 1797 in the first edition of tlie Nereis Britannica (2d fascicle, p. 

 xvi), but in tlie second edition (1816, p. xii) evidently abandoned 

 in favor of " Leniarkea." There is an earlier generic name, Codia 

 (Forster and Forster, 1776, p. 59), still used for a genus of Saxi- 

 fragaceae, and CodiaeiDii of Rumphius (1743, p. 65) is still current 

 among the Euphorbiaceae. Otto Kuntze (1891, p. 900) argues for 

 "Lamarckia" as the propi^r designation, but Codium, properly diag- 

 nosed (for the period), has been in almost universal use for nearly, 

 if not quite, a century, and has the right of way now that llic status 

 of the name of Lamarkin has been settled as indicated above. 



The genus Codium contains somewhat over twenty-five described 

 species agreeing closely in microscopic structure, but differing very 

 decidedly in habit. Some are flat expansions, some are expanded but 

 ciLshion-shaped, some are spherical and hollow, while some are either 

 cylindrical or flattened but erect and l»i'anching. J. G. Agardh (1886, 

 p. 35 et seq.) has suljdividcd the genus according to these differences. 

 After habit, good characters for distinction of the species have been 



