i ü ' r
i'llI
I" A
' ii'
rated by distinctions so minute and variable, that they cannot be maintained
as other than varieties, and Zygnema malleohcm and Z. afiine were
a t the time suspected of being varieties the one of the other,
Plate X X X V II. fig. 1. Variety gi-acilis. a, sterile cells X 200 ; 6,
conjugating cells with zygospores X 200 ; o, fertile cells of Bhyncho-
nema form with zygospores X 200 ; d, outline zygospores X 400. Pig. 2,
yarietj flavescens. a, sterile cells X 200; &, c, conjugating cells with
zygospores X 200; d, fertile cells of Pliynchonema form with zygospores
X 200 ; e, outline zygospores X 400. Fig. 3, variety parva. a, sterile
cells X 200; b, conjugating cells with zygospores X 200; c, outline
zygospores X 400.
S e c t io n 2 . C e l ls r e p l i c a t e a t t b e e n d s .
A, Chlorophyll hands usually two or more.
Spirogyra in s ig n is . Hass.
Sterile cells witb the extremities replicate, 41 to 5 (rarely 6)
times as long as broad, chlorophyll bands 2 to 8, lax, with 1 to 2
turns of spiral, or nearly erect.
Spores ovate-elliptic, twice as long as broad, membrane even.
Sporiferous cells slightly swollen.
S i z e . Sterile cells -OS-'OSS mm. Zygospore -04--05 mm.,
2 to 3 times as long.
Eabh. Alg. Eur. iii. 243.
Zygnema insigne, Hass. Alg. 440, t. 103, f. 1,2.
Zygnema HassalUi, Hass. Alg. 157, t. 36, f. 4 ,5 . Jenner FI.
Tunb. Wells, 182.
Spirogyra insignis, Kutz. Tab. v. t. 31, f. 4. Sur. Ohs.
t. 1, f. a.
Rhynchonema HassalUi, Kutz. Tab. v. t. 32, f. 7.
Spirogyra Braunii, Eabh. Alg. Ex. No. 1310, 1395.
Spirogyra Hantschii, Eabh. Alg. Ex. No. 1291.
Spirogyra Theohaldii, Kntz. Tab. v. t. 31, f. 2.
Spirogyra HassalUi, P e tit Bull. Soc. Bot. F r.; Spirogyra t , 2,
f. 6-8.
Rhynchonema galUcum, Ripart. in P e tit Spirogyra.
In streams.
The number of British species in which the cells have replicate ends
is much less than of those with truncate ends. We have only included
.two species with two or more chlorophyll bands, in one of which the
membrane of the zygospore is smooth, and in the other punctate. Doubtless
neither of them are common.
Plate X X X V III. fig. 1. a, d, sterile cells X 200 ; b, conjugating cells
with zygospores X 200; c, fertile cells of Rhynchonema form X 200;
outline zygospore X 400.
Spiiogyza ca lo spo ia . Cleve 3Ion. Zyg. p. 26, t. 8,f. 1-6.
Sterile cells with the extremities replicate, 6 to 12 times as long
as broad, chlorophyll bands 1 to 8, making 2 | to 7 turns.
Spores elongate, obtuse ovoid, q to 2 times as long as broad,
membrane yellow, scrobiculate.
Sporiferous cells scarcely turgid.
form a major.
Diameter of threads ’05 mm. Bands 2 to 3.
form ¡3 minor.
Diameter of threads •032 mm. Band single.
S i z e . Zygospore ■078--096 x -045 m m .
Archer in Quart. Journ Mior. Sci., 1873, xiii. p. 436. Pe tit
Spirogyra p. 11, t. 2, fig. 11-13.
Spirogyra protecta, Wood. F . W. Alg. t. 14, f. 3.
In bogs and moor pools.
Plate X X X V I II . fig. 2. a, sterile cells X 200; h, c, conjugating cells
with zygospores X 200 ; d, outline zygospore X 400.
B. Chlorophyll hands single.
Spirogyra quadrata. (Hass.) Petit.
Sterile cells 3 to 9 times aslong as broad. Fertile cells turgid,
quadrate. Zygospore elliptical. Sporoderm brown.
S i z e . Cells ’024 to '027 mm. Zygospore •042-’048 mm.
diam., q to 2 times as long.
P e tit Spirogyra p. 8, t. 1, fig. 13. Bull. Soc. Bot. France
xxi. p. 14, t. 1, fig. 2.
Zygnema quadratum, Hass. Alg. 157, t. 37, f. 1, 2. Jenner
FI. Tunb. Wells, 182,
Rhynchonema quadrata, Kutz. Tab. Phy. v. t. 32, f. 6.
In pools.
We have accepted Petit’s diagnosis of this species, which Hassall had
seen only with the Rhynchonema mode of conjugation, but which has
now been ascertained to conjugate in both ways. His description is very
short for a species which he says is “ by no means uncommon,” and he
evidently depends as a specific feature on the quadrangular enlargements
of the fertile cells. “ Cells usually seven or eight times as long as
broad. Sporangia oval, large, and much elongated, contained within
quadrangular enlargements of the cells.”
Plate XXXIX. Jig. 1. a, fertile cells in conjugation with zygospore
X 1^00, after P e tit; &, zygospore in cell x 'iOO*
Spirogyra W eberi. Kutz.
sterile cells with the extremities replicate, 7 to 12 times as
long as th e diameter, chlorophyll bands single, 3 to 8 turns of
the spiral.
Spores ovoid, scarce broader than the sterile threads, membrane
even, chestnut, twice as long as broad.
Sporiferous cells scarcely turgid.
S i z e . Spores : ( a ) '072 x -034 mm. {¡3) -068 X ’034 mm.
Cleve Monog. Zygn. p. 25, t. vii,, f. 1-10-
form a. insequalis.
Diameter of thread -03 mm. Sporiferous cells scarcely
longer than the spores.
Zygnema incequale, Hass. Alg. 150, t. 32, f. 1 to 2.
Zygnema intermedium, Haas. Alg. t. 87, f. 3. Ann. Nat.
Hist. X. (1842) p. 41. Jenner I?!. Tunb. Wells, 182.
'■ 'i