nr
li
I
Plate X X X V I. fig. 1. a, sterile cells X 200 j h, conjugating cells with
zygospores X 200; c, sterile cells of inflated form X 200; d, conjugating
cells with zygospores x 200 ; e, /, g, outlines of zygospores X 4Ò0.
Spirogyra lon g a ta . Vauch.
Sterile cells with the ends truncate, 3 to 8 times as long as
broad, chlorophyll bands single or rarely two, making l i to
6 turns of a spiral.
Spores ly to 2 times as long as broad, membrane even, chestn
u t colour.
Sporiferous cells swollen and usually longer than the spore.
S iz e . Cells -024--03 mm. diam. Zygospore •04--07 x -03 mm.
Cleve Monog. Zygn. p. 20, t. 3, f .8 - 1 0 ; t. 4, f. 1-7 : t. 10,
f. 11-18.
Conjugata longata, Vauch. Conf. p. 71, t. 6, f. 1.
In pools and ditches.
var. a. communis.
Sterile cells 3 to 8 times as long as broad.
Spirogyra longata, Kutz. Tab. v. t. 20, f. 1. Rabh. iii. 238.
P e tit Spirogyra t. 5, f. 4, 5.
Zygnema commune, Hass. Alg. t. 28, f. 5, 6. Ann. Nat. Hist.
X. (1842) p. 39. Jenner PL Tunb. Wells, 180.
Zygnema aistivum, Hass. Alg. t. 28, f. 3, 4. Ann. Nat. Hist
xi. (1843), p. 433. Jenner FL Tunb. Wells, 180.
Zygnema angulare, Hass. Alg. t. 34, f. 1, 2. Jenner FL
Tunb. Wells, 180.
Zygnema angulatum, Hass. Ann. Nat. Hist. x. (1842) p. 41,
Zygnema reversum, Hass. Alg. t. 33, f. 3.
Zygnema alternatum, Hass. Alg. p. 154.
Z jgm m a mirabile, Hass. Alg. t. 35, f. 1-3.
Spirogyra communis, Kutz. Tab. v. t. 19, f. 4. P e tit Spirogyra
t. v. f. 1-3.
Rhynchonema angulare, Kutz. Tab. v. t. 34, f. 1. Rabh. iii.
232.
Rhynchonema reversum, Kutz. Eabh. iii. 232.
Spirogyra subtilis, Kutz. Tab. v. t. 19, f. 5.
Spirogyra mirabilis, Kutz Sp. p. 438. Pe tit Spirogyra p. 14
t. 3, f. 3-4. ’
Conjugata longata. Gray Arr. i. 279 (?)
var. ¡3. tu ip is .
Sterile cells abbreviated.
Zygnema malformatum, Hass. Alg. t. 30, f. 1, 2 Ann Nat
Hist. X. (1842) p. 39. Jenner FL Tunb. Wells, 180.
Zygnema catmneforme, Hass. Alg. t. 30, f. 3, 4. Ann. Nat
Hist. X. (1842), p. 39.
Zygnema abbreviatum, Hass. Alg. t. 34, f. 4.
Spirogyra turpis, Kutz. Tab. v. t. 19, f. 2. Rab. iii. 238.
Spirogtjra catceneformis, Kutz. Tab. v. t. 19, f. 1. Rab. iii.
238. P e tit Spirogyra t. 3, f. 9-12.
Rhynchonema abbreviatum, Kutz. Rab. iii. 248.
We venture to differ from our friend Mona, Petit in uniting four of hia
species. In fact, if four species are to be accepted, we see no logical
grounds for refusing fco accept a dozen, because of the excessive variability
in the sterile cells.
PUte X X X V I. Jig, 2. a, b, sterile cells X 200; c, conjngating cells
with zygospores X 200; d, fertile cells of Rhynchonema form with zygospore
X 200; e, fertile cells of mirabilis form with zygospores X 200;
f , conjugating cells of oatenaiformis form with zygospores X 200 ; g, A, i, ]c,
outline zygospores X 400.
Spirogyra fla v e sc en s. (Hass.) Cleve.
Sterile cells with the ends truncate, 2} to 5 times longer than
broad, chlorophyll bands single.
Spores attenuated, twice as long as broad, membrane even,
chestnut colour.
Sporiferous cells swollen, and usually longer than the spores.
S iz e . Cells -02 mm. diam. Zygospore -05 x -024 mm.
Cleve Monog. Zygn. p. 19, t. 3, f. 6, 7.
Boggy pools on heaths, &o.
fo7'm a. g r a c ilis.
Zygospore about '03 mm. diam.
Zygnema gracile, Hass. Alg. t. 30, f. 5, 6.
Spirogyi'a gracilis, Kutz. Tab. v. t. 18, f. 5. P e tit Spirogyra
p. 15, t. 3,f. 7, 8.
Zygnema malleolum, Hass. Alg. t. 84, f. 5.
Rhynchonema malleolus, Kutz. Tab. v. t. 33, f. 3.
form b. fla v e sc en s .
Zygospore about -02 mm. diam.
Zygnema flavescens, Hass. Alg. t. 30, f. 9, 10. Jenner FI
Tunb. Wells, 180.
Spirogyra flavescens, Kutz. Tab. v. t. 18, f. 4. P e tit Spirogyra
p. 15, t, 3, f. 5, 6.
Zygnema affine, Hass. Alg. t. 34, f. 6.
Spirogyra affinis. P e tit Spirogyra, p. 18, t. 3, f. 12, 13.
Rhynchonema affine, Kutz. Tab. v. t. 33, f. 2.
form c. parva.
Zygospore about -01 mm. diam.
Zygnema parvum, Hass. Alg. t. 30, f, 7, 8, Ann. Nat. Hist.
X. (1842) p. 41. Jenner FL Tunb. Wells, 180.
Spirogyra parva, Kutz. Tab. v. t. 18, f. 8.
This species includes five of Hassall’s species of Zygnema, which subsequently
were relegated by Kutzing, three to Spirogyra and two to
Rhynchonema. The Zygnema flavescens, parvum, and gracile, are sepa