492 University of California Publications in Botany [you 6 



are up to 80/^ thick. The thickened utricles on the material at my 

 disposal are in the margin, and especially in the underside of the 

 thallus, and those on the underside of the thallus are not fruiting. 

 Another characteristic feature of the thick walled utricles, which has 

 not been mentioned either hy Svedelius or by Miss Hurd. is the 

 papillate thickenings on the outer surface of the thickened portion 

 (pi. 42, fig. 8). This character does not appear at all in any of the 

 specimens which I have referred to C. Setchellii. The first notice pub- 

 lished of such modifications of the end walls of C odium utricles is 

 that of Howe (1914, pp. 45, 46) as occurring in his C. foveolatum. 

 Some years ago Professor Setchell noticed similar markings on the 

 utricles of a C odium from Hawaii, probably undescribed. In this 

 connection, I may mention a modification of the end walls of a speci- 

 men labelled C. adhaerens collected by M. A. Howe (no. 2055, Herb. 

 Univ. Calif, no. 77292), from Porto Rico, differing from all of the 

 above mentioned modifications in being on the inside surface of the 

 wall (pi. 42, fig. 9). Similar modifications may have previously been 

 overlooked on other described species, but in those in which it occurs 

 it seems of sufficient diagnostic value as to be useful in making specific 

 distinctions. 



The fronds of C. dimorplium, as described and figured by Svedelius, 

 are variously separated more or less into small lobes and are 5 mm. 

 thick. Tho.se of C. Setchellii are widely expanded, at times more or 

 less lacerated, and are up to 15 mm. thick. 



C. Setchellii differs from C. difforme Kuetz. as figured by Vickers 

 (1908. pi. 25) in having the utricles less branched and with thicker 

 end walls, and in having the sporangia much longer and narrower than 

 in that species. 



Rhizoclonium lubricum Setchell et Gardner sp. nov. 



Plate 42, fig. .5 



Fills flaccidis, Inbricis. totaliter cylindrieis. 3-4.5 dm. Inngis, laete 

 viridibus; segmcntis 35-50/x. vulgo 40/x, diam.. quiescentibus 4-6 plo 

 diam., post divisionem 1-2 plo diam., longis ; chromatophoris parietal- 

 ibus laxe reticulatis; pyrenoideis parvis, numerosis, in segmentis quies- 

 centibus, 40-50; parietibus 2fj. crassis, homngeneis; ramis rhizoideis 

 Curtis non septatis, cum cellulis generantibus continuis, sparsis; 

 zoosporis gametibusque ignotis. 



Filaments flaccid, lubricous, straight, cylindrical throughout, 3- 

 4.5 dm. long, pale green ; segments 35-50|a, mostly 40/a diam., resting 



