f
S p iio g y ra ju g a lis . (Dill.)
Sterile cells with the ends truncate, and commonly equal, or
double the length of the diameter. Chlorophyll bands 4 to 5,
making 1 to 2 turns.
Zygospore elliptical, membrane even.
Sporiferous cells not swollen.
S iz e . Sterile cells -Og-'l mm. diam. (P e tit),-lA mm. diam.
(Cleve), 'OTS-’l mm. diam. {Rabh.), •087-’l l mm. diarn.
(Kirsch.). Zygospores -14 x - l - ’ffi mm. (Cleve), -15 x -1
mm. (Petit), -IS-'M x -08.5--09 mm. (M.C.C.).
Conferva jugalis, Dillw. Brit Conf. t. 5.
Spirogyra jugalis, Kutz. Tab. v. t. 27, f. 2 ; P e tit Spirogyra
p. 2 9 ,1 .11, f. 8, 4 ; Rabh. Alg. Eur. iii. 245.
Sph-ogtjra setiformis. Pe tit Spirogyra, p. 29, t. 11, f. 1, 2
(not Kutz., nor Rabh. Alg. Eur.)': Rabh. Exs. 2292 ; Cleve
Mon. Zyg. p. 15 (partly), t. 1, f. 1-3.
In clear ponds, &c. Fruiting a t Midsummer.
The British specimens which we refer to this species have the sterile
cells from '12 t o '14 mm. broad, and about two diameters long. The
zygospore is from T3 to T4 mm. long and '085 mm. broad. In other
specimens, from the Continent, we have found the zygospores from *11
to *13 mm. long and *095 mm. broad. M. Petit recognises two species,
which he calls respectively S. jugalis and S. setiformis, differing so little
from each other that it seems scarcely possible to distinguish them except
in extreme cases. To the latter he refers Z. interruptmn of Hassall,
but, without the fruit, which Hassall never found, it is difficult to affirm
what it might be. I t is quite as probable that it was S, orbicularis as
anything else.
Plate XXXII. f g . 2. a, sterile cells X 200; b, fertile cells with
zygospores X 200; c, outline of zygospore X 400.
S p iio g y ra n itid a . (Dillw.) Link Bandik. m ., 262.
Sterile cells with the ends truncate, and usually 2 to 4 times
as long as broad ; chlorophyll bands about 4, making 1 to 4
turns of the spiral.
Spores elliptic ovoid (almost almond-shaped), l i times as
long as broad, membrane even.
Sporiferous cells persistent.
Germinating plant clavate, radical cell much attenuated.
S iz e . Sterile cells *072-*078 mm. diam. (Petit), *08- 09
mm. (Cleve), *06-*075 mm. (KaiA), *054-*077 mm. (K irsch ),
•07-*09 mm. (M.C.C.). Zygospore *1 x *072 mm. < C leve),-W-
*13 X *06-*07 mm. (M.C.C.).
Spirogyra princeps, Cleve Monog. Zygn. p. 16, t. 1, f. 4 to 7.
Conjugataprinceps, Vauch. Conf. p. 64, t. 4, f. 1.
Zygnema nitidum, Lyngb. Tent. Hydr, t. 59, f. B. Hass.
Alg. t. 22. Harv. Man. p. 143. Eng. El. v. 362. Eng. Bot.
Ed. ii. t. 2509. Mack. El. Hib. 231. Hook. FI. Scot. ii. 80.
Dickie Bot. Guide 296.
Spirogyra nitida, Kutz. Tab. Phy. v. t. 27, f. 1. Kirsch.
Alg. Schl. p. 123. Pe tit Spirogyra p. 28, t. 10, f. 6 to 10.
Conferva nitidum. Dill. Clonf. t. 4, f. C. Eng. Bot. ed. i. t.
2337. Jenner B’l. Tunb. Wells 178. Gray Arr. i, 298.
Zygnema rostratum, Hass. Alg. t. 33, f. 1.
In ponds, &c.
Very little requires to be said of this species, which is the most
common one with thick filaments in Britain. I t is most probable that
Hassall’s Zygnema rostratum is the same, conjugating longitudinally, for
he says that the filaments are somewhat larger than those of his
Zygnema nitidum, but that he had only seen it once. The form of
zygospore figured by him is that of the present species, and not of
Spirogyra bellis, to which the Rhynchonema rostrata of Kutzing is re-
ferred by Cleve.
Cleve proposed to substitute the name of Spirogyra princeps, Yauch.,
for the universally known Spirogyra nitida, a change with which we by no
means sympathise, because, after all, it is only a matter of opinion, and
not of demonstration, whether this is really the Conjugata princeps of
Tauoher, and there should be a good and substantial reasons for superseding
a specific name so long recognised as Spirogyra nitida.
Plate X X X I I I . Jig. 1. a, h, sterile cells X 200; c, conjugating ceils
with zygospores X 200 ; d, outline of zygospore X 400.
S p iio g y ra orthospira. Ndg. in Kutz. Bpec.p. 441.
Sterile cells with the extremities truncate, and from 2A to 4
to 10 times as long as broad ; chlorophyll bands 3 to 4 to 5
(rarely 7), sometimes erect, sometimes forming a very lax
spiral.
Spores orbicular, flattened, membrane even.
Sporiferous cells scarcely swollen, 2^ to 4 times as long as
the diameter.
S iz e . Cells *05-*065 mm. d iam .; zygospore *07 mm. diam.,
*048 mm. thick.
Spirogyra orthospira. Archer in Quart. Journ. Micr. Sci.,
1870. P e tit Spirogyra p. 80, t. 10, f. 4, 5.
Spirogyra majuscula, Kutz. Tab. Phy. v. t. 26, f. 1. Eabh.
Alg. iii. 244.
In pools. Fruiting in autumn.
^ This is a recently discovered species in the British Islands, and has
hitherto only been recognised by Mr. Archer in Ireland.
Plate X X X I I l . Jig. 2. a, a, sterile cells X 200; b, conjngating
cells with zygospores X 200; c, front and side views of zygospore X
400.
Spixogyra oxbiculaxis. Hassall Alg, t. 19.
Sterile cells with the ends truncate, about equal in length to
breadth; chlorophyll bands 5 to 7, making ^ to 1 turn.
Zygospores orbicular, flattened, membrane punctate.
Sporiferous cells not inflated.
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