7. Osc il lato ria pu l c h e l la Ilass.
PLate L X X . Pig. 5.
Char. Filaments thick, straight, hrittle, vivid green. Striæ
close, very conspicuous.
Ilab. Bottom of pools near Stocket, Aberdeen : Dr.
Dickie. Cheshunt : A. H. II.
The filaments of this fine species are more robust than those
of O. virescens and the striæ closer. The only other described
species with which it could be confounded is O. spadicea,
which it resembles in the closeness and strength of the striæ ;
but the filaments in O. pulchella are rather finer and much
more brittle.
8. O scillatoria virescens Hass.
P late L X X I . Fig. 9.
Char. Stratum terrestrial, o f a light ceruginous green colour.
Filaments o f considerable diameter, pale yellowish green
straight, brittle. Striæ subdistant.
Ilab. Cheshunt, Herts : A. H . H. Between River Head
and Chipstead, bankside : Mr. Jenner.
This Avould appear to be a distinct as Avell as a fine species.
The filaments are longer than those of O. tenuis, and moreover
preserve their diameter in drying. Striæ nearly a diameter
of the filaments apart, conspicuous.
9. Oscillatoria thermalis Hass.
Plate L X X I I . Fig. 3.
Char. Filaments small, green. Striæ straight, hrittle, subdistant,
very evident.
Hab. In a stream of hot Avater, Stevenston : Rev. D.
Landsborouyh.
The filaments of this species are as slender as those of O.
terebriformis, but of a different colour, and the striæ are much
more evident.
10. Oscillatoria splendida Grev.
P la te L X X I I . Fig. 8.
Char. Stratum bright æruginous or bluish green, thin, with
short rays. Filaments arachnoid, straight or curved,
Striæ wholly invisible.
Grev. Flor. Edin., p. 304. ; Harv. Br. Flor. 375. ; Harv.
Manual, p. 164. O. membranacea, O. amphibia and
O. elegans Ag.
Hab. In tubs of w ater in the stove of the Botanic Garden,
Edinburgh : Dr. Greville.
This is the most slender of all the Oscillatorioe. The
stratum exactly resembles in colour and appearance tha t of
either O. limosa or O. tenuis, from Avhich it may be immediately
detected by the microscope. Agardh has described
this species under no less than three different names, as I
have ascertained from an examination of authentic specimens
in the Herbarium of Sir W. J . Hooker.
11. Oscillatoria autumnalis Ay.
P late L X X I I . Fig. 7.
Char. Stratum o f a deep æruginous green, with a metallic
lustre, very lubricous. Filaments very slender. Striæ
subdistant.
O. autumnalis Ag. Syst. p. 62. ; Grev. Flor. Edin. p. 305. ;
Harv. 1. 0. p, 376.; Harv. Manual, p. 165.
Hab. Appin : Carmichael.
The filaments of this species are very slender, not being,
more than tAvice the diameter of those of O. splendida. They
cohere closely, and are usually very much broken when examined
under the microscope. Striæ not very evident, subdistant.