F a m i l y IY. LEMANEACBÆ.
l i '» .
Fluviatile algie. Thallus developed from a confervoid pro-
thallio filament, setaceous, almost simple, hollow, nodose, having
an internal and a cortical laj'er of cells. Polyspores numerous,
collected in branched moniliform series, germinating without
fertilization.
Genus 121. L EM A N E A . Bonj. (1808.)
The only genus in tbe family, with tbe same obaraoters as above
given.
“ The dilated portions of the threads are loosely filled with the spores,
which are produced within the frond. The spores are oval, thick-walled
cells, joined together to form series, which are very much branched, so
that from a central basal row they rise as a complex bush-like mass. The
first step, according to Wartmann, in their germination, consists in the
elongation of the spore, and the projection of one end, which is soon cut
off by the formation of a transverse partition, and constitutes a new cell.
This multiplication soon develops into abranched confervoid filament. A
large number of these filaments are generally produced in one place at
one time, and form a very apparent greenish layer. Finally, certain cells
in branches of these filaments swell up and become very much broader
than their fellows, undergoing, at the same time, division so rapidly that
they become very short. By-and-bye they divide also in the direction
of their breadth, so that, instead of a simple series of cells, there arises
a compound mass. This is the beginning of the new frond. At first it
is dependent npon the parent filament, but soon acquires a root-like process
at the base, and develops rapidly into the complex cartilaginous
plant.”—Wartmann, Beitrage zur Lemanea (1864).
L em a n e a f lu v ia tilis . Ag, Spec. Alg. ii. p. 4.
Simple, or sparingly braucbed, 3-4 inches long, straigbt,
nodules ratber remote, witb about tbree verticillate papillee.
S i z e . S p o r e s ’0 4 X '0 2 5 m m .
Eabb, Alg. Eur. iii., 4 1 1 . Kircb. Alg. Scbles. 43. Eng. Fl. v.,
p. 822. Hook. Fl. Soot, ii., 84. Eng. Bot. ii., t. 2423. Jenner
Tunb. Wells 176. Harv. Man. 119. Johnst. Fl. Berw, ii.,
246. Mack. Hib. 220. Gray Arr. i., 288. Hass. Alg. 72.
Lemanea corallina, Bory Ann. de Mus. x x ., t. 21, f. 2.
Conferva fluviatilis, Dill. Oonf. t. 29. Hull Br. Fl. 332.
Eng. Bot. i., t. 1768. Huds. Ang. ii., 597. W ith . A rr. iv.,
134. Lightf. Fl. Soot. 985.
Conferva fluviatilis lubrica setosa equiseti facie, Dill. Muse. 39,
t. 7, f. 47.
Nodularia fluviatilis, Grev. Fl. Ed. 800. Fl. Devon, ii., 57.
“ From a cartilaginous disc, strongly applied to foreign bodies, proceed
a great number of close filaments, elastic, of a brownish-green colour,
and a little curved at the base, but they beoome more pale and straight
in the remainder of their length. These filaments are ordinarily from 4
to 7 inches in length. Some are entirely simple, the others throw out
here and there branches, or divide towards the middle of their length.
The internodes are oblong, from a line to a line and a half, cylindrical,
and inflated at their points of contact. Their divisions are often but little
apparent, aud disappear towards the base of the filaments, which appear
continuous, cylindrical, and equal in diameter to a strong horse-hair.
The surface of the filaments in old age is encrusted in such a manner as
not to beoome recognizable either by its colour, which changes, or by the
destruction of the internodes, which beoome confused and disappear.”—
Attacbed to stones, wood, &c., in streams.
Plate C X X V I I I . fig. 1. Filaments natural size ; a, portion of filament
magnified ; b. section of same ; o, chains of spores x 200.
L em a n e a to iu lo s a . {Roth.) Ag. Spec. ii. 4.
Nearly simple, for tbe most part bent like a bow, 1 - 2 inches
long, nodules approximate, papillæ flattened, sometimes confluent
or almost obsolete.
S iz e . S p o r e s '0 4 -x -022-'03 mm.
Eabh. Alg. Eur. iii., 411. Kiroh. Alg. Sohles. 43. Eng.
Fl. V., 322. Gray Arr. i., 288. Hass. Alg. 71, t . 7.
Conferva torulosa, Dillw. Conf. p. 77, t. f.
Conferva fluviatilis nodosa fucum emulans, Dill. Muse. t. 7,
f.48.
Lemanea fluviatilis, var. R. torulosa, Eng. Bot. ii., t. 2423.
Harv. Mon. 119.
Conferva fluviatilis, var. 2. W itb . Arr. iv., 134.
In streams.
“ From a little horny disC, fixed to the hard bodies which support it,
arise from six to thirty filaments, from one inch to 2J inches in length,
curved in one direction. Their colour is of a brownish or reddish.green,
obscure or livid. They acquire in diameter the greatest dimensions of
all the Confervæ.”—Bory.
Bory states that “ M. Thore, of Dax, first remarked, in the Conferva
fluviatilis of Linnæus, a fact which is verified in the other species of our
genns. The recent filaments of this Lemaoiea, presented towards the
flame of a candle, explode and extinguish the candle. This phenomenon
does not take place in dried specimens. I t is owing to some gas shut
np in the connections of the joints, and which, put in expansion by the
heat, presses against the walls and breaks them with an explosion. A
remarkable movement of retraction is experienced in the fingers which
hold by the two extremities tho filament experimented upon. As to the
smell of the burnt plant, although very peculiar, it cannot be compared
to)that of animal substances submitted to the fire. I have not met with
any hemania in stagnant waters ; they grow in quick waters. It is in
the pure fountains, large rivers, in very rapid rivulets, that they appear
to delight. Many, moreover, flourish especially in those places where
the current has the greatest force, such as in mill sluices, aud the most
impetuous falls of cascades.”—Hassall’s Alga, p. 70.
Plate CXXVIII, fiy. 2. Filaments natural size.