P. B.-A. specimen No. 456, Easton’s Pt., Newport, R. I., belongs to this variety rather than the type, as shown by the scrobiculate spore wall. In Mr. Bullard’s collection there are also specimens of the variety from Pennannock, N. J., and from Spy Pond, Lake St., Arlington, Mass.
Cellulis vegetativis 24-30µ × 70-180µ, dissepimentis replicatis; chromatophoris singulis, rarius duobus, anfractibus arctis 2.5-6; cellulis fructiferis inflatis (ad 39-60µ); zygosporis ellipticis, polis plus minus acuminatis, 32-45µ × 48-93µ, membrana media glabra, lutea.
Vegetative cells 24-30µ × 70-180µ, end walls replicate; 1 (rarely 2) chromatophore making 2.5-6 turns; fertile cells inflated to 39-60µ; zygospores ellipsoid, ends more or less pointed, 32-45µ × 48-93µ, median wall smooth, yellow. Type in herb. E. N. T. Coll. No. 2955, 2956, 2957.
In Mr. Bullard’s collection there are specimens of this species from Lexington, Arlington, and Middlesex Fells, Mass. The P. B.-A. specimen No. 362, labeled _S. Grevilleana_, from Medford, Mass., belongs here, rather than to _S. Grevilleana_, in which the spores are distinctly ovoid with broad rounded ends.
This interesting form is characterized by quadrately inflated fertile cells, highly refractive cell walls, and unusually long cells and spores. In Mr. Bullard’s collection there are specimens from Stony Brook, South Framingham, Middlesex Fells, Wayside Inn, North Eastham, and Malden Fells, Massachusetts. The P. B.-A. specimen No. 363 labelled _S. inflata_, Orange, Conn., belongs to this species.
This species is one of several forms near _S. insignis_ (Hass.) Kützing. If Wille’s description is correct and identical with Hansgirg’s material, then _S. inconstans_ Collins becomes a synonym of _S. fallax_. Hansgirg’s figure suggests that the filaments in his material are homosexual. While Wille’s description and figure suggests that the filaments are reflexed and that conjugation does not regularly occur between parallel filaments, with the spores all in one filament. It is difficult to decide just where these rough-spored forms belong as the earlier authors did not pay much attention to spore markings. In this connection the note by Professor Nordstedt in connection with specimen No. 958 in Wittrock and Nordstedt’s Algae Exsiccatae is of interest. Until these forms have been clearly separated by a study of the original collections it seems best to use _S. fallax_ for _S. inconstans_, of which the type is P. B.-A. No. 1568. Here also belongs P. B.-A. No. 1570, Middlesex Fells, Mass., and P. B.-A. No. 1571, Wakefield, Mass.