1920] Setchell-Gardncr : CJilorophyceae 173 



Howe {loc. cit.) refers a plant from La Paz, Lower California, 

 to this species, apparently with some confidence, and at the same 

 time he selects Codiiati droorticatum as the correct name instead of 

 C. elongatiini. We have not seen Howe's plant, but certain questions 

 arise as to tlie exact nature of C. dccorticatuni and of C. dongatum. 

 The type specimen of Ulva decorticata Woodward {loc. cit.) is 

 unknown and the type reg^ion is given as the Mediterranean Sea with 

 tlie statement that the exact locality was unknown to the author. Tlie 

 type locality for C. dongatum Ag. (1822, p. 454) is Cadiz, Spain. 

 The species is related to C. tomentosum, l)ut differs in being more 

 elongated, with fewer and longer branches, and in being more or less 

 distinctly dilated and flattened just below the axils (or some of them). 

 Such a plant is figured by Kuetzing (1856, pi. 96 b), but liis phuit 

 came from Rio Janeiro, Brazil, a tropical locality. Bornet (1892, 

 ])p. 216, 217) has given his experience with C. dongatum and his 

 attempts to ascertain the characters upon which separation could be 

 made from C. tomentosum. He considered two sets of characters, viz., 

 the extent of infra-axillary dilation and the magnitude of the utricles. 

 Bornet decided to separate the species according to the presence or 

 absence of dilations, and to subdivide the species with dilations (C 

 dongatum) into a variety with large utricles and one with small 

 utricles, since tliis fulfilled the idea of C. Agardh and also corre- 

 sponded with the geographical distribution. Codium dongatum with 

 .small utricles extends north along the Atlantic coast of France and 

 to England, while C. dongatum with large utricles does not extend 

 north of Cadiz. In this connection it is interesting to note again that 

 Cadiz is the type locality of C. dongatum, and to note also that the 

 type specimen of C. dongatum is, according to Howe (1911, p. 495), 

 provided with slender utricles. The tropical forms referred to C. 

 elongatum (or C. decorticatum^.) have stout utricles as Kuetzing has 

 described and figured {loc. cit.). We suspect that there may be two 

 overlapping species of somewhat similar habit, but differing in utricles 

 and in geographical distribution, represented under C. decorticatum. 

 It may be that C. decorticatum (Wood.) Howe, being a IMediterranean 

 species (subtropical), may finally be separated from C. dongatum 

 Ag., the more northern (temperate) species which reaches its southern 

 limit near Cadiz and Tangiers, and there intermingles with tlic large 

 utricled form {C. decorticatum?) as Bornet has found it. Howe's 

 plant from La Paz is described as having large utricles (up to 520/x 

 diam.) and must therefore be arranged with the larger fonn of Bornet. 



