S. fallax (Hansgirg) Wille.
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.
S. floridana nov. sp.
Cellulis vegetativis 56-66µ × 120-335µ, dissepimentis planis; chromatophoris 4-5, subrectis vel anfractibus arctis .5; cellulis conjugatis abbreviatis, inflatis (ad 135µ) et geniculatis; canalis conjugationis brevis et latis; zygosporis ellipticis, 75-105µ × 95-135µ membrana media glabra, lutea.
Vegetative cells 56-66µ × 120-335µ, end walls plane; 4-5 chromatophores, nearly straight or making a half turn; conjugating cells geniculate, shortened; fertile cells inflated up to 135µ; conjugating tube very short and broad; zygospores ellipsoid, 75-105µ × 95-135µ median wall smooth, yellow. Type in U. S. National Herbarium, collected by J. D. Smith, in S. W. Florida, March, 1878.
In its dimensions S. floridana is intermediate between S. stictica (Eng. Bot.) Wille and S. ceylanica Wittrock. In several publications the statement is made that S. ceylanica is intermediate between S. stictica and the common forms of Spirogyra. A study of authentic material of this species has shown that it has not intermediate characters, but with its spores having a minutely pitted median wall, it seems to be intermediate between S. floridana and S. illinoiensis Transeau, the most specialized form in the Sirogonium group of the genus.
Throughout the study of these collections the writer has been greatly assisted by Mr. Hanford Tiffany, now a teacher in the Charleston, Illinois, High School. It is a pleasure to acknowledge my indebtedness to the many collectors who have sent me specimens for study.