2C6 PROCEEDINGS OF THE AMERICAN ACADEMY 



ther study shows, however, that the number of cells seen in cross- 

 section varies from four to eight ; and it may be remarked that, in 

 most of the species belonging to the subgenus Stlchocarpus, the number 

 of cells is too inconstant to constitute a specific character. 



Dasya trichoclados 3IerL var. Oerstedi, J. Ag. = Dasya lopho- 

 clados Mont., Ner. Am. Bor. II. p. 65. 



T^NiOMA Clevelandii, n. sp. fronde capillacea erecto-cpespitosa 

 ad 4 pollicares ; ramis flexuosis irregulariter pluries pinnatis, ramulis 

 ad basem contractis, ultimis subulatis incurvatis ; articulis subcom- 

 pressis, 4 siphouiis fere ecorticatis, 2 siphoniis lateralibus marginatis ; 

 stichidiis nunierosis sparsis vittfeformibus tetrasporas oppositas foven- 

 tibus in apicem subacutum abeuntibus. — San Diego, Cal., INIr. D. Cleve- 

 land. — But two species of this genus are as yet known, T. perpusillum 

 Ag., found by Liebmann on the west coast of Central America, and T. 

 macrourum Thur., found by Schousboe at Tangier. We should naturally 

 expect the first-named species to occur at San Diego ; but, as it is de- 

 scribed by Agardh as closely resembling CalUthamnion Rothii in habit 

 and mode of growth and having subfesciculate stichidia, it would hardly 

 seem as though the plant collected by Mr. Cleveland, which has scat- 

 tered stichidia, is four inches high, and has a striking resemblance to 

 Griffithsia tenuis Harv., could belong to the same species. The 

 specimen sent by Mr. Cleveland is unfortunately broken off near the 

 base ; but, judging from what was sent, there seems to be no creeping 

 primary filament. From T. macrourum the present species differs in 

 having the stichidial branches terminate in a more or less acute apex 

 instead of two hairs. When seen in front view, the frond shows a 

 series of articulations, each of which is composed of three subequal 

 cells bordered on both sides by a wider cell. A cross-section is rather 

 narrowly elliptic, and shows four subequal cells arranged round a 

 central cell, as in many species of Polysiphonia ; but each of the cells 

 lying in the longer axis of the ellipse has a cell in contact with it on 

 the outer side and of about the same size as itself, so that the short 

 axis of the ellipse is composed of two, and the long axis of four, cells 

 besides the central cell. In the lower part of the frond, the angles 

 between the primary cells are filled with a small but irregular number 

 of secondary cells. 



Polysiphonia senticulosa Harv. This species, described in the 

 Jour. Proc. Linn. Soc, Vol. VI. No. 24, p. 169, is apparently common 

 along the whole Californian coast. It admits of question whether the 

 species should not be considered a variety of Pol. urceolata. 



Polysiphonia secunda Ag. Under this species is included by 



