A p h an izom en on ilos-aquæ. Ann. Nat. Hist. t. 9, /. 6.
Floating, forming a pale or dark blue green stratum on the
surface of tbe water. Trichomes very thin, nearly straight,
aggregated in membranaceous flakes which readily separate,
eitber distinctly or indistinctly articulated, very pale blue or
colourless. Joints oylindrioal, about as long as broad, slightly
granular. Spores more or less elongated cylindrical, 6-12 times
as long as broad, granular.
S iz e . Cells 'OOS-'OOJ mm. diam. Spores -005 X •03-'04
mm.
Allman, Quart. Journ. Micr. Sci. 1855, p. 21, t. 3.
Byssus flos-aqucB, Linn. Spec. Plant. (1753) No. 1168.
Limnochlide flos-aquæ, Kutz. Tab. Phyo. i., t. 91, f. 2, a.
Aphanizomenon incurvum, Morr. Bull. Brux., 1839, Harv.
Man. 145, Hass. Alg. 280, t. 76, f. 6 .
Sphærozyga flos-aquoe, Eabh. Alg. Eur. ii., 195.
In ditches, ponds, and meres.
One of the species of Algæ which contribute to the phenomena characterized
as ‘ ‘ breaking of the meres,” Professor Allman thinks that he
has observed heterocysts (see Micr. Journ. p. 22), but this is not confirmed.
Plate XCIY. fig. 1. a, Trichomes in bundles, X 20Ü ; i, Trichomes,
with spores X 400.
Genus 97. SPHJEROZYGA. (Ag) Ralfs. (1850.)
Triobomes involved in an amorphous, often very quickly
diffluent, mucilage, rarely vaginate, agglutinated in an indefinite
gelatinous stratum ; joints spbærical, elliptical or oblong,
transversely compressed and often quadrangular. Heterooysts
intercalated, binary, or solitary. Spores originating in cells
placed on each side of the heterocysts.
Sp hæ io zy g a C a im ich a e li. Harv. Phyc. Britt, t. 113.
Stratum thin, of a dark or bluish green colonr when recent,
but opaque and glaucous when dry. Trichomes moniliform,
witb tapering extremities ; joints distinct, somewhat quadrate.
Heterocysts sphærical. Spores oblong.
Siz e . Cells -OOSb-OOdS mm. Heterocysts -006 mm. diam.
Spores -008--01 X -018--025 mm.
Kutz. Tab. Phyc. i.,t. 99, f. 4. Kalfs Ann. Nat. Hist. 1850,
t. 8, f. 7. Kabh. Alg. Eur. ii., 191.
Belonia torulosa, Carm. Eng. El. v., 379. Harv. Man. 167.
On damp soil in salt marshes flooded at spring tides, in
brackish ditcbes, &c.
“ The best distinctive mark of this speoies is the subaoute extremities,
combined with the short filament and littoral habitat. There are rarely
more than one or two groups of enlarged cells, when only one is present
it is situated near the centre of the filament. I believe that the attenuated
extremities are constant, at least iu the young plant, unless the filament
has been broken.”—Eai/s.
Plate XOIV. fig. 3. Portions of trichomes with heterooysts and
spores X 400.
Sphæzozyga Bzoomei. Thwaites in Harv. Phyc. Britt.
Stratum bluish or yellowish green. Triobomes moniliform,
joints subsphærical. Heterocysts smooth, subquadrate, ra tber
longer than wide. Spores numerous, elliptical, twice as long as
wide, not much exceeding in width the joints, commencing to be
formed on either side nex t to the heterocysts.
S iz e . Cells -004 mm. Heterocysts -005 X "006 mm.
Spores -008 x '016 mm.
Thwaites in Harv. Phyc. Britt, t. 173, fig. A. Ealfs Ann.
Nat. Hist. (1850) t. 8 , fig. 10.
On dead leaves of Myriophyllum in brackish ditch.
“ The gelatinous matrix is firmer than in many speoies of this genus.
The numerous spores iu each series distinguish it from every other species
I am acquainted with.”—Ea Z/s.
Plate XCIV. fig. 4. Portions of triobomes, with heterooysts and
spores X 400.
Species imperfectly lenoivn.
Spliæirozyga B e zk e ley an a . Thwaites in Harv. Phyc. Britt.
Young trichomes included, one or several together in a defined
mucous sheath. Joints sphærioal, compressed. Heterocysts
sphæroidal, slightly compressed. Spores usually two on
each side of the heterooysts, large, twice the width of the joints,
oblong, balf as long again as wide, becoming brown when
mature.
S iz e . Cells about •006-'007 mm. Spores about -012 x
•015 mm.
Thwaites in Harv. Phyo. Britt, t. 173, fig. B. Ealfs Ann.
Nat. Hist. 1850, 384, t. 8 , fig. 11.
Amongst Cladophora fracta, in brackish ditch.
Mr. Ealfs says : “ The turgid spores and large compressed heterocysts
characterise this species,” of which we have no knowledge.