f "I
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Spirogijra inmqualis, Kutz. Tab. y. t. 80, f. 3.
Zygnema Orevilleanum, Hass. Alg. 149, t. 31, f. 1, 2. Hass.
Ann. Nat. Hist. x. 38. Jenner FI. Tunb. Wells, 180.
form b. su b v en tiic o sum .
Sporiferous cells 2 to 4 longer than tbe spores. Diam. -026 mm.
Spirogyra Weheri, Eabh. Alg. Eur. iii. 233.
Zygnema sub-ventricosum, Hass. Alg. 150, t. "32, f. 4, 5. Jenner
FI. Tunb. Wells, 180.
Zygnema diductvm, Hass. Alg. t. 37, f. 4,
Rhynchonema diductnm, Kutz. Tab. y. t. 32, f. 3.
Spirogyra ventricosa, Kutz. Tab. v. t. 29, f. 5.
Zygnema ventricosvnvUBSs,. Ann. Nat. Hist. x. (1842) p 38.
Zygtiema longaium, Hass. Alg. 151, t. 31, f. 3, 4.
In ditches. Fruiting in summer.
The absence of any measurements, or uniformity in magnification in
the figures, renders it very difficult to determine many of Hassall’s
species with any certainty. From present information we are unable to
recognise Z. Gremlleanum as a distinct species.
PUte X XX IX . ßg. 2. a, sterile cells X 200 ; b, c, conjugating cells
^gospTrirX200^ ^ ’^y^'^T.onema iorm yriüx
Spirogyra ten u is sim a . Hass.
Sterile cells with the extremities replicate, 5 to 15 times as
long as the diameter. Chlorophyll bands single, making 3 to 6
turns of the spiral.
Spores broader than the sterile cells, elongated ovoid, twice
as long as the diameter, membrane even and chestnut colour
Sporiferous cells turgid.
S iz e . Spore -055 (a)--058 (ß) x -024 (£z)--03 mm. (ß).
Cleve Monog. Zygn. p. 24, t. 6, f. 5-7.
form a, ten u is sim a .
Sterile cells 8 to 16 times as long as broad. -012--015 mm
diam.
Sporiferous cells 2 to 3 times as long as the spores.
Zygnema tenuissimum, Hass. Alg. t. 32, f. 9,10. Ann. Nat.
Hi.st. X. (1842) p. 41. Jenner PI. Tonb. W., 180.
Zygnema minimum, Hass. Alg. t. 37, f. 8. ’
Spirogyra tenuissima, Kutz. Tab. v. t. 29, f. 2. Eabh Affi
Enr. iii. 233.
Rhynchonema minimum, Kntz. Tab. v. t. 38, f. 1.
Spirogyra Naegelii, Kutz. Tab. v. t. 29, f. k ’
form i. inflata.
Sterile cells 5 to 10 times as long as broad. •017--02 mm
diam.
Sporiferous cells scarcely longer than the spores.
¥
Zygnema varians, Hass. Ann. Nat. Hist. xi. (1843) p. 431.
Conjugata inflata, Vauoh. Conf. p. 68, t. 5, f. 3.
Zygnema injlatum, Hass. Alg. t. 32, f. 6, 7. Jenner FI. Tunb
Wells, 180.
Zygnema Jenneri, Hass. Alg. t. 37, f. 6. Jenner FI. Tunb
Wells, 182.
Zygnema duhium, Hass. Alg. t. 37, f. 7.
Spirogyra gastroides, Kutz. Tab. v. t. 29, f. 4.
Rhynchonema Jenneri, Kutz. Tab. v. t. 32, f. 1.
Rhynchonema dubium, Kutz. Tab. v. t. 32, f. 2.
Spirogyra inflata, Rabh. Alg. Eur. iii. 233.
In pools.
This species includes the most delicate of British species with replicate
ends to the cells. In all the forms of both varieties there is an
evident tendency in the fertile cells to become more or less inflated. The
only difference which Hassall indicates between his Z. injlatum and Z.
tenuissimum is one of size, which may be influenced by the circumstances
of growth.
Plate X X X IX . jig. 3 , a, sterile cells X 200; b, conjugating cells of variety
a, with zygospores X 200 ; c, conjugating cells of variety b, with
zygospores X 200; d, outline of zygospores X 400.
Genus 46. S IR O G O N I tm KuU. (1843.)
Cells with parietal longitudinal chlorophyll bands. F ru c tifying
cells diverse, arising by unequal division of the thread-
cells, bending knee-like towards each other and growing
together, united a t the point ofadnation ; reoeiving-oells barrelshaped
; giving-cells short, cylindrical. Zygospore (elliptic) in
the receiving cell-wall.
'The sterile cells, with parallel chlorophyll bands, resemble those of
Spirogyra, but differ iu the genuflexuous conjugation.
Sizogonium s tic tic um . Kutz.
Sterile cells 2 to 5 times as long as broad.
Zygospore broadly elliptical, spore-coat double.
Sporiferous cells swollen, abbreviated.
S iz e . Cells '04 to '05 mm., 2 to 5 times as long. Zvgospore
■042 X ’075 mm.
De Bary Conj. p. 78, t. 2, figs. 1-6. Rabh. Alg. Eu r. iii,, 256.
Sirogomum breviarticulatum, Kutz. Tab. Phy. v. t. 4.
Sirogonium Braunii, Kutz. Tab. Phy. v. t. 4.
Conferva stictica, Eng. Bot. t. 2463.
Zygnema curvatum, A g . Eng. FI. v. 362. Harv. Man. p.
143. ^ Eng. Bot. Ed. ii. t. 2512, f. a . Hassall Alg. 143, t. 26,
f. 1 , 2 .
Choaspes serpentina. Gray Arr. 1, 299.
In ponds and ditches and moor pools.
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