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114 SIPHOrHYCEA:.
Farther modes of increase are—
5. Cell division.
6. Formation of spores.
7. Formation of zoospores.
This plant possesses also fivefold resting stages-
1 . d i the asexual zoospores laid in water—for months.
2 . Of the root cells—the year throughout in which they
originated. ^ . i...
3 . Of the hypnosporanges—the year throughout in which they
originated.
4. Of the spores—for years. _ , . ,
5. Of the isospores—at least over the year in which they
originated.
Plate LTV., Botrydium gramnlatum. Fig. 1, plants of the natural
size. Fig. 2, zoosporangium X 30. Fig. 3, the same, five hours atter-
wards, with the zoospores escaping at the apex, X 30. Fig. 4, zoospores
X 520 Fig. 5, differentiation of the plasma in the root, and the torma-
tion of root cells, X 30. Fig. 6, root cells in water producing zoospores
X 160. Fig. 7, the resulting zoospores X 520. Fig. 8, the same, 24 hours
after swarming, X 520. Fig. 9, the same, four days later, X 520. Fig.
10, the same, eight days later, X 620. Fig. 11, copulating swarmspores
X 520. Fig. 12, zoospores derived from a spore, after six and a naii
hours, X 160. F ig . 1 3 , s e x u a l swarmspores iu conjugation X 520. Fig.
14, isospores, 24 hours old, X 520. Fig. 15, stellate isospores, more than
a day old, X 520. Fig. 16, young plant resulting from vegetation ot
isospore. All after Eostafinski and Woronin.
Botrydium g ranulatum . Linn.
Usually gregarious, often aggregated, rarely confluent; cells
globose, pyriform, size of a poppy seed, or mustard seed, or
larger, leek-green, apparently pulverulent.
Botrydium granulatum, Jenn. FI. Tunb. Wells 176. Parfitt
in Grevillea i., p. 10. Eng. FI. v., p. 321. Harv. Man. 150.
Kirsch. Alg. Schl, p. 84. Trans. Bot. Soo. Edin. vi., 424. Eng.
Bot. ii., p. 127, t. 2422. Hass. Alg. t. 77, f. 5.
Hyd.rogastrum granulatum, Eabh. Alg. Eur. iii., 265. Desv.
El. Ang. 19.
Lichenoides fungiforme, Ray Syn. ill., p. 70.
Tremella palustris, Dillen. Hist. Muse. 55, t. x., f. 17.
Botrydium argillaceum, Grev. Alg. Brit., p. 197, t. 19. Kutz.
Tab. vi., t. 54. ^
Vaucheria granulata, Grev. PI. Ed. 306. Gray. Arr. t., 290.
Vaucheria radicata, Hook. El. Soot, ii., 93.
Vaucheria multicapsularis, Harv. Man. 149. Gray Arr. i.,
252 (?).
Ulva granulata, Lightf. El. Scot. 976. Hull. Brit. FI. 309.
Tremella granulata, Huds. FL Ang. 566. With. Arr. iv.,
80. Eng. Bot. L, t. 324.
On the ground in swampy places.
“ The plant about I J mm. diam. ; the upper portion, or that above
ground, globular, gradually narrowing downwards, and passing into one
or two principal roots, which become gradually ramified into many fine
rootlets; the chlorophyll contents at the begmning dense and homogeneous,
and clothing the inner cell membrane, extend only to the n e o t
of the ro o t; the membrane is rather rigid. Upon being broken the cell
contents become extruded, the membrane collapses as a thick pellicle,
whose contents admit of being completely pressed out. The fluid
contents in this condition consist of finely granular plasma, tinged by
chlorophyll granules. Subsequently the green plasma layer becomes
separated from the membrane, breaks up into single equal-sized portions,
which become rounded off, coated with a membrane, and gradually
individualized as daughter-oells. At last the entire globose cell is
densely filled with rounded danghter-cells ; whilst, previous to this state,
the plant presented an intensely grass-green colour, it shows in this
latter state a clear or sea-green colour. Mature and immature plants
hence readily admit of being distinguished by the tint with the unassisted
eye. The membrane of the mother individual at last passes to decay;
it collapses, and the daughter-oells become the germs of new individuals
in the soil- The maturity ot the individuals occurs towards
autumn, and accordingly the germ cells lie resting in the earth during
winter, and germinate in the following spring. The development of the
germ cells to new individuals takes place without formation ot a
‘ prothallus ’ (‘ohne Torkeimbildung’). One end elongating as a root,
a t once penetrates the earth ; the other end becomes developed as the
above-ground portion. The diameter of a ripe germ cell is 0-009-0'U12
mm. The plants prefer to establish themselves on the surfaces of the
large clefts which are produced when the waters retreat and the ground
becomes gradually dried by the air.”—Reinsch. Algen Flora, p. 218.
See also “ Grevillea ” Yol. iv., p. 105, since which period the Memoir by
Eostafinski and Woroniu has appeared, and that has pretty well established
the complex character of reproduction in this little plant.
F amily II. VAUOHFRIACF^.
Algte monsecious (rarely diasoious), CDSspitose, unioellular or
bicellular. Thallus with terminal vegetation, utriole-shaped,
elongated, more or less branched.
Propagation either sexual, by oospores fecundated by sper-
matozoids, or non-sexual by zoospores.
Sporangium terminal, formed by the globosely clavate swelling
of the tip of the thallus, cut off by a septum, contents dark
green, at length enclosing one large zoospore, densely clad with
vibratile cilia.
Oogonium lateral, sessile, or borne on a more or less elongated
simple, or partite, pedicel ; cytioplasm a t length converted into
a large oospore.
Antheridium lateral, sessile, or cut off by a septum from the
upper portion of a lateral branch, in which numerous spermato-
zoids are generated, which a t length become free. Spermatozoids
oblong, furnished with two unequal cilia (except iii one
species).
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