S. Borgeana nov. sp.
Cellulis vegetativis 30-35µ × 50-200µ, dissepimentis planis, chromatophoris singulis anfractibus arctis 1.5-5; cellulis fractiferis altero latere inflatis, altero latere (in quo conjugatio sequitur) rectis; zygosporis ellipticis, 33-40µ × 54-70µ, membrana media flava, glabra.
Vegetative cells 30-35µ × 50-200µ, end walls plane, 1 chromatophore making 1.5-5 turns; fertile cells inflated on the outer side, straight on the conjugating side; zygospores ellipsoid 33-40µ × 54-70µ, median wall yellow, smooth. Type in herb. E. N. T. Coll. No. 1883, 1890. Charleston, Illinois.
This species bears some resemblance to a form of S. varians figured by Professor Borge.[D] It differs from his figure in that the conjugating side of the fertile cells is not at all swollen, and the dimensions are somewhat larger. If this form had been found but once it would have been passed over as a variation intermediate between S. Juergensii and S. varians. But it has been found several successive years in a small stream south, and at a small pond west of Charleston, Illinois.
S. lutetiana Petit.
So far as I am aware no specimens of this species have been found in America. The Illinois record in my list[E] is an error. The P. B.-A. specimen labelled S. lutetiana is S. fallax (Hansg.) Wille, as shown by its often replicate cell walls, verrucose spores and the number of chromotophores.
S. velata Nordstedt var. occidentalis Transeau.
Specimens of this variety have been distributed in the P. B.-A. No. 96, under the name of S. dubia Kütz. var. longiarticulata Kütz. from Oak Bay, Victoria, British Columbia (N. L. Gardner). The spores are for the most part not mature but they show the characteristic scrobiculate markings of the median wall.
S. Lagerheimii Wittrock.
This species is not uncommon in central Illinois. The specimen labelled S. communis in P. B.-A. No. 1416, from Winchester, Mass., has a cell diameter over 30µ, and the spores are ellipsoid instead of ovoid. The median spore wall in the mature spores is punctate. Here also belongs the P. B.-A. specimen No. 365, Falmouth, Mass. Both the vegetative cells and the spores are considerably below the lower dimensions for S. porticalis. The P. B.-A. specimen No. 1668, S. porticalis var. tenuispira Collins establishes this name as a synonym of S. Lagerheimii. Professor Farlow has recently sent me a specimen of this species from Chocorua, N. H.