290 
will be possible to see the particular specimen on which the re- 
port was based. 
The limits of genera among desmids are so unsettled that 
hardly any two writers agree in all points. Especially is this true 
of the genus Cosmarium. No attempt has been made to settle 
the points in dispute. In nearly every case the specimens have 
been compared with the original figuresand descriptions. Where 
the variation from the type is slight varietal names have not been 
used, as it seems useless to encumber our literature with a long 
list of varieties, many of which represent simply forms of a vari- 
able species. 
In the enumeration of species only the more noteworthy ones 
from the various localities are mentioned, although careful record 
has been made of ail species observed, and specimens have been 
preserved. Species new to the United Statcs are marked with an 
asterisk. 
Pleurotaenium nodosum (Bail.) Lund. Near Tallahassee, Fla. 
Scarce. Surface of cell smooth; ends ornamented with a circle 
of conical-rounded granules. 
Docidium verrucosum (Bail.) Ralfs. Frequent in various col- 
lections from Florida. Walle’s figures do not give a correct idea 
of this beautiful species. The elevations are nearly square, except 
those of the terminal circle, which are elongated. The apex of 
the semi-cell bears a crown of rounded granules. The Florida 
specimens resemble the figures of Joshua’s D. tesse//atum*, and it 
seems to me that the latter must be regarded as a synonym of D. 
verrucosum, 
D. coronulatum Griin. Occasional at Meredith, N. H. Sev- 
eral cells were often found joined in series. Diam=—=25-35 ps 
This is apparently the same species figured by Wolle under 
this name. Griinow’s original measurements are larger, and the 
cells as figured by him were slightly different in shape. 
Penium annulare West. Baton Rouge, La. Frequent. Found 
by W. West in material from Maine, and described by him’. The 
2 Joshua, W. Burmese Desmidieae, with descriptions of new species occurring in 
the neighborhood of Rangoon. Journ. Linn. Soc. 21 : 650. pl, 25. f. 15. Je. 1886. 
3 West, W. The Freshwater Algae of Maine. Repr. from Journal of Botany 
1894: (2) pl. 775. f. 5.6. D. 1891. 
