Spirogyi'a quinina, Kutz. Tab. v. t. 22, f. 2.
Spirogyra porticalis, P e tit Spirogyra, p. 21, t. 5, f. 8-12.
Conferva spiralis, Dillw. Conf. t. 3. Eng. Bot. Ed. i. t. 1656.
Zygnema sph'alis, Eng. Bot. Ed. ii. t. 2561.
Conjugata quinina. Gray Arr. i. 297.
vcur. ¡3. d ecimina.
Cbloropliyll bands usually 2, sometimes 3.
S iz e . C e l ls ■ 0 3 4 --0 4 m m ., 2 to 4 t im e s a s lo n g .
Zygnema deciminum, Hass. Alg. t. 23, f. 3, 4. Harv. Man.
p. 143. Jobnst. FI. Berw. ii. 255. Mack. FI. Hib. 2, 31. FI.
Devon ii. 50. Jenner FI. Tunb. Wells 178. Grev. FI. Edin.
320. Eng. FI. v. 362.
Spirogyra decimina, Kutz. tab. v. t. 23, f. 3, 24, f. 1. P e tit
Spirogyra p. 25, t. 8, f. 1-3. Rabh. Alg. iii. p. 242.
Spirogyi'aflavicans, Kutz. tab. v. t. 23, f. 8.
Spirogyra laxa, Kutz. Tab. v. t. 23, f. 3.
Spirogyra major, Kutz. Tab. v. t. 24, f. 2.
Conferva jugalis, Dillw. Conf. t. 5.
Conferva inflata, Eng. Bot. Ed. i. t. 2376.
Zygnema injlatum, Eng. Bot. Ed. ii. t. 2510. Hook. PL
Scot. ii. 80.
Conjugata inflata. Gray Arr. i. 297. (?)
Conjugata decimina. Gray Arr. i. 299.
var. c. r iv u la iis . Hass.
S i z e . Cells -032--036 mm., 5 to 10 times as long.
Zygnema rivulare, Hass. Alg. 144, t. 27, f. 1, 2. Annals
Nat. Hist. X. 8 8 .
Spirogyra rivularis, Rabh. Alg. Eur. iii. 243.
Undoubtedly if the sterile threads of this species are carefully examined,
they will furnish abundant evidence that the number of spiral
bands is variable, for cells will constantly be found in the same filament
in which either one or two bands occur. So that, with the great similarity
in fruit, it would be folly to think of maintaining the two varieties
decimina and quinina as distinct species, on account of the number of
chlorophyll bands. The Z. rivulare of Hassall, which we have included
as a third variety, is not uncommonly found in a sterile condition, in so
far as it can be determined iu this stage, but hitherto we have not seen
it in fruit. I t is said to he found on the Continent in fruotifloation, bnt
we have no knowledge of the Continental form. The spirals in the
sterile ceils are usually three, and then very nearly identical with the
condition of the variety decimina, in which the bands are the same in
number,
Plate X XX V. fig. 1, iorm quinina. a, sterile cells X 200; I, c, conjugating
cells with zygospores X 200 ; if, outline zygospores X 400. Fig. 2,
form decimina. a, sterile cells X 200 ; i, conjugating cells with zygospores
X 200 ; d, outline zygospore X 400. Fig. 3, form rivularis. a,
sterile cells X 200.
9 1
C. Chlorophyll hands single.
Spirogyra condensata. Vauch.
Sterile cells with the extremities truncate, and commonly
1 to 3^ longer than the diameter. Chlorophyll bands single,
rarely two, making 1-^ to 2 turns of the spiral.
Spores broadly obtuse, ovoid, or siibspherioal, membrane even,
chestnut colour.
Sporiferous cells turgid, and usually shorter than the spores.
S iz e . Cells -04 mm. diam., zygospores -OSh-'Od mm. diam.
Cleve Monog. Zygn. p. 21, t. v. f, 1-7.
Conjugata condensata, Vauoh. Conf. t. 5, f. 2. Gray Arr.
i. 298.
Zygnema varians, Hass. Alg. t. 29, f. 3 and 4. Jenner
PL Tunb. Wells, 180.
Zygnema Woodaii, Hass. Alg. t. 83, f. 2. Jenner FL Tunb.
Wells, 180.
Spirogyra torulosa, Kutz. Tab. v. t. 20, f, 2.
Spirogyra nodosa, Kutz. Tab. v. t. 20, f. 3.
Spirogyra arcta, Kutz. Tab. v. t. 21, f. 2.
Spirogyra condensata, Kutz. Tab. v. t. 22, f. 3. Petit Spirogyra,
p. 22, t. 9, % . 6-8.
Rhynchonema Woodsii, Kutz. Tab. v. t. 84, f. 2 (not of Nord.
and Wittr, Exs., No. 789).
Spirogyra Flechsigii, Eabh. Hedw. i. p. 46.
Zygnema quininum, var. Hass. Aun. Nat. H ist.x . (1842) 35.
Spirogyra ulotrichoides, Kutz. Tab. v. t. 2 1,f. 3.
Spirogyra varians, Kutz. Sp. Alg. p. 439. P e tit Spirogyra
p. 49, t. 4, f. 1-8.
Spirogyra inflata, Kutz. Tab. y. t. 21, f. 1-8.
In pools. F ru itin g in spiring.
From the number of synonyms quoted above, it may be inferred that
this is a variable species. All the forms seem to he included by Petit
under his Spirogyra condensata and S. varians.
Hassall thus alludes to a peculiar nodoluse growth of some of the
forms ;—“ When a number of cells unite in regular order with those of a
neighbouring filament, no inflation of any of these occurs ; but it frequently
happens that several adjoining cells of a filament for some reason
or other do not unite, although the remaining ones in that filament do,
in which case those which have not yoked themselves swell up, assuming
a monoliform appearance, and at the same time frequently emit blind and
irregular processes or prolongations, by which the cells manifest the
strong tendency which they have to conjoin themselves, but which some
cause, not evident, would appear to have frustrated. In some specimens
the number of inflated cells and blind processes is bnt small,
while in others the elongated cells are more numerous than those which
have united in the ordinary manner.” A similar circumstance may
sometimes be observed in 8. longata, especially iu the short-celled
forms.