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Mack. Hib. 239. Gray. A rr. i., 281. Eng. Fl. t . , 374. Eng.
Bot. ii., 2525.
In ditches, swamps, inundated places, now and then free
swimming ; throughout the year.
Very variable, passing into several moderately distinct varieties, of
■which the bright green one called viridis is the most beautiful, and by
no means rare.
The form which Carmiohael called Oscillatoria contexta has thns been
described by him ;—“ Stratum of indefinite extent three feet and upwards,
exceedingly thin, and peeling off in large flakes iu dry weather,
of a deep but shiuiug black colour, scored or striated iu all directions.
These striæ are caused by thick fasciculi of filaments, shooting out
either parallel to or across each other, changing their course from time
to time and sending off lateral fasciculi. The filaments are rather thick
about a line in length, straight or variously curved, of a greyish green
colonr, and they radiate with great rapidity. A portion of the stratum,
not more than a line in diameter, placed in a watch-glass, filled with
water, overspread the whole area ot the glass with filaments iu the
course of a night.” Hassall says of it, “ the filaments are in calibre not
leas than those of 0. tenuis, from which speoies it is distinguished
chiefly by its colour.”
Plate XOVI. fig. 8. Portions of trichomes X 400. PUte XOVII,
Jig. 1. Portions of trichomes of the variety viridis X 400.
Oscilla ria . a n t l i a r ia . Jurgens Alg. Exs. No. 14.
Expanded in a gelatinous, sometimes very broad submem-
branaceous stratum, dark steel-blue. Trichomes rigid, straight,
sometimes tranquil, sometimes oscillating, curved at the attenuated
apex (curvature of 3 to 4 joints) ; joints equal, or nearly
equal,in length and breadth (after division half as long), dissepiments
distinctly granular, extreme apex obtusely rounded. Cell-
oontents pale steel-blue, or blue green, nearly homogenous.
S i z e . T h r e a d s -0045-'0055 m m . d i am.
Kutz. Tab. Phyc. i., t. 40, f. 6. Rabh. Alg. Eur. ii., 100.
Oscillaria parietina, Vauch. Conf., t. 15, f. 8 .
Around pumps, cisterns, &o.
plate xcyll. fig. 2. Portions of trichomes x 400.
O s c illa z ia m u s c o rum . Carm. MS8.
Stratum 3-4 inches, of a dark bluish-green colour, slightly
lubricous, shortly radiating, creeping over mosses. Trichomes
variously curved, pale blue green, joints about equal in length
to their diameter.
S i z e . Trichomes 'OOG-'OOI mm. diam.
Hook. Eng. Fl. v., 365. Harv. Man. 164. Hass. Alg.
252, t. 72, f. 12.
In rapid streams, on Hypnum ruscifolium, &o.
“ Stratum 3 or 4 inches in extent, closely interwoven with the branches
and leaves of mosses, of a bluish green colour, and slightly lubricous
Pilamenta a line or two in length, variously curved and radiating ;
striæ a t the distance of a diameter from each other.”—Garmichael.
Plate XCV I I I . fig. 8. Portions of trichomes X 400, from the
original specimens.
Osc illazia su b u lifo zm is, Thw. in Harv. Phyc. B ritt.
Stratum of an intense æruginous green. Trichomes bright
green, subuliform, gradually attenuated towards the apices, which
are subacute and much curved ; joints about three-fourths as
long as broad, homogenous.
S iz e . Trichomes ■0 0 6 -‘0 0 7 mm. diam.
Harv. Phyc. Britt, t. 2 5 1 b . Rabh. Alg. Eur. ii., 2 9 2 .
In brackish ditches. Summer and autumn.
Very bright emerald green, and certainly an attractive speoies.
Plate X C V III. fig. 3. Trichomes from original specimen X 400
diam.
Oscillairia lim o sa , Ag. S y s t Alg. 66.
Trichomes rigid, straight, actively oscillating, blue-green,
interwoven in a thin mucilaginous radiating green stratum,
distinctly articulate, joints nearly equal or a little longer than
broad (shorter after division, often half as long as the diameter),
dissepiments granulated, apex obtuse, straight or
curved ; cell-contents pallid, homogenous or slightly granular.
S i z e . Threads 'OOS-’Ol mm. diam.
Rabh. Alg. Eur. i., 1 0 4 . Hook. Br. Fl. ii., 3 7 4 .
Conferva limosa, El. Dan. t. 1 5 4 9 .
Oscillatoria limosa, Hass. Alg. 2 4 6 , t. 7 1 , f. 2 . ( ? ) Eng. Fl.
V . , 3 7 4 . Gray. Arr. i . , 2 8 0 . Eng. Bot. ii., 1 8 6 . Harv. Man.
1 6 2 . Johnst. Fl. Berw. ii., 2 6 5 . Mack. Hib. 2 3 9 . Fl. Dev.
ii., 5 6 .
Oscillaria tenuis d. limosa, Kirch. Alg. Sohles. p. 2 4 7 .
There are several varieties, differing chiefly in colonr, of which Rabenhorst
enumerates ten.
I f Hassall’s figure is magnified in proportion to the rest, then his t. 71,
f. 2, can scarcely be the present species, for its diameter would be equal
to that of 0. Frolichii, whereas this scarcely exceeds half that thickness.
All the figures of Oscillaria given in Hassall’s work are acknowledged to
be very defective.
Plate XC V II, fig. 3. Portions of trichomes X 400. Pig. 4, portions
of trichomes of the variety chalybea X 400.
Osc illa z ia izzigua. Kutx. Phyo. Gen. 189.
Stratum thin, expanded, compact, dark steel-blue, by oblique
light purplish violet ; trichomes straight, flexile, pallid then
livid steel blue, a little attenuated at tbe apex, joints equal in
length to their diameter (after division half as long) dissepi-
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