1^20] Setchell-Gardner : Chlorophycaae 167 



7. Codium Stackh. 



Thallus spongy, not incrusted with lime, applanate, subspherical 

 or cylindrical, simple or dichotomously 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 fragmentation of 

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

 duced in gametangia situated laterally on the utricles; dioecious or 

 occasionally monoecious. 



Stackhouse, Nereis Brit., 1797, p. xvi. Lamarckia Olivi, in 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 the Nereis Britannica (2d fascicle, p. 

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

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

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

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

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

 "Lamarckia" as the proper 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 the status 

 of the name of Lamarkia 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 

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

 cylindrical or flattened but erect and branching. J. G. Agardh (1886, 

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

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



