Spirogyra longata (Vaucher) Kütz.

*? SPIROGYHA LONGATA. ^g! | ^ |

SPIROGYRA LOFGATA, fVATTCH.J KTZ. - Fresh-water Algae of the United
States page 18, February 1872. (Smithsonian contribution to
knowledge. 241* •

Sp* dense caespltosa, laete luteolo-viridis, yalde lubrica; arti-
culis sterilibus diametro 2-6 plo longiorlbus, fertllibus saepe
Tnmidis abbreviatis; fascia spirali lata, dentata; anfractibus
sublaxis 2-5; zygosporis ellipticis.

Diam.- Q*001n.

Syn.-Conjugate longata, VAUCBER, Histoire des Conferves d’Eau donee,
p. 71.

Sp.longata, (VAUCH.> EETZIliG. BA3EITH0RST, Flora Burop. Algarum,
Sect. III. p. 238.

Hab.-In stagnis, prope Philadelphia; WOOD. Rhode Island; (S. T.

Olney) Thwaites.

Densely oaespitose, bright yellowish-green, very slippery;
sterile Joints 2-6 times longer than broad; fertile articles
swollen, often abbreviate; ohlorophyl filaments broad, dentate;
turns of the spiral somewhat loose, 2-5; zygospores elliptical.

REMARKS.-According to Prof. Rabenhorst, this Bpecies attains in Europe
a diameter of *0011” and the cells a length of 8 times their
breadth. The same authority also describes the fertile cell as
being either not swollen, or moderately so (”aut non aut modice
tumidis"). In all the Specimens of our American forms which
I have seen, the sporangial cells are very decidedly swollen.

Fig. 4, pi. 14, represents portions of sterile filaments, mag-
nified 250 diameters and fig. 4 a, a part of a fertile pair of
filaments containing immature spores enlarged 260 diameters*

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