Vegetative cells 7.5-9µ in diameter, zygospores 24-30µ × 30-42µ steel blue, otherwise like the type.
Debarya americana nov. sp.
Cellulis vegetativis 9-12µ × 27-120µ, ad dissepimenta constrictis; chromatophoris cum pyrenoidibus 2; cellulis fructiferis, 10-14µ × 75-180µ; zygosporis ovoideis vel quadrato-ovoideis, 20-40µ × 30-40µ, angulis rotundatis, productis, vel retusis; parthenosporis 15-20µ × 20-30µ, oblique ellipticis, cum polis retusis; mesosporio subtiliter et irregulariter verrucoso, maturitate luteo-brunneo.
Vegetative cells 9-12µ × 27-120µ constricted at the end walls, chromatophore with two pyrenoids; fertile cells 10-14µ × 75-180µ; zygospores ovoid or quadrately ovoid, 20-40µ × 30-40µ, with angles rounded, produced, or retuse; parthenospores 15-20µ-× 20-30µ unilaterally ellipsoid with retuse ends; median spore wall minutely and irregularly verrucose, yellow-brown at maturity.
This species was collected by Professor A. B. Klugh, Kingston, Ontario. It is the material upon which the Ontario record for Mougeotia calcarea (Cleve) Wittr. is based. Of special interest is the chromatophore with two pyrenoids, which although an axile plate is distinctly two-lobed and forms an easy transition to the next species, in which the chromatophore resembles Zygnema. Type in herb. E. N. T. Collection No. 2950.
Debarya decussata nov. sp.
Cellulis vegetativis 16-20µ × 25-50µ cylindraceis; chromatophoris asteroidiis duobus, singulis cum pyrenoidibus (ut in Zygnemate); zygosporis vel ovoideis, vel irregularibus, 24-30µ × 30-48µ cum angulis vel rotundatis, vel retusis, vel productis; aplanosporis uno latere ovoideis, 17-25µ × 20-40µ; parthenosporis 15-20µ × 20-30µ; membrana media sporarum scrobiculata, luteo-brunnea; akinetis ad dissepimenta constrictis, membrana subcrassa et glabra, 18-20µ × 20-36µ.
Vegetative cells 16-20µ × 25-50µ cylindrical; chromatophores two, stellate, each with a pyrenoid (as in Zygnema); zygospores ovoid, quadrate-ovoid, or irregular, 24-30µ × 30-48µ, with rounded, retuse, or produced angles; aplanospores unilaterally ovoid, 17-25µ × 20-40µ; parthenospores 15-20µ × 20-30µ; median spore walls scrobiculate, yellow-brown; akinetes with smooth heavy walls, 18-20µ × 20-30µ.
Type in herb, E. N. T. Collections No. 1177, 1939, 1949, 2686 and 2918. I have specimens from several localities in central Illinois; Williamsport, Pa.; Minnesota; Mackinaw, Mich. and Kingston, Ontario.
This form is of great interest because of its resemblance, in the vegetative condition, to Zygnema decussatum (Vauch.) Transeau. Also because it shows not only the zygospores, but aplanospores and parthenospores. In all cases the secretion of cellulose accompanies the process of spore formation. The unilaterally placed aplanospores are strikingly different from those formed by the Zygnemas. In some of the Illinois ponds it regularly produces only zygospores, in other ponds from which I have collections covering a period of several years it fruited only asexually, producing aplanospores and akinetes. But several of the collections show all the forms of reproduction in different cells of the same filament.