196
A. D. BONEY
to some disturbance because of their shallow nature, and of low salinity
due to influx of fresh water, e.g. north-east side of Tokyo Bay. Mini0
(1949) described its occurrence in the lagoon of Venice. All evidence
points to the species being able to tolerate a wide range of environmental
conditions.
Very few plants are fertile in Norway and the standing crop is
maintained by vegetative propagation, and regenerative growth was
obtained from fragments 2 mm to 2 cm in length (Stokke, 1957). Such
development, however, was obtained at temperatures between 14"18"CJ and not a t 10°C. Humm (1944) described how free-living Brucilaria plants in the seas offshore in North Carolina showed rapid growth,
and the standing crop formed the basis of an agar industry. Causey
et ul. (1946) showed that growth of Gruciluriu in North Carolina took
place in a temperature range of 1Oo-25"C. I n South Africa the species
is a component of both the cold-water flora on the west coast, and is
also to be found in the warmer seas near Port Elizabeth (Isaac, 1956).
In both these regions the plants grow best in sheltered waters, and the
mean annual temperature range approaches 15°C. Detached fragments
of Gruciluria two inches in length produced new apical and lateral
branches. Jones (1959a) measured the change in weight of both
tetrasporic and cystocarpic plants whilst immersed in the sea, and found
that increase in fresh weight was slow during autumn and winter, and
showed a more noticeable increase in May. This increase in weight was
maintained through June and the rate of change started to slow down
in July and August, and into the autumn. The nature of the growth
process in the tetrasporic and cystocarpic plants appeared to difFer
somewhat, since the increased growth rate was later than with the plants
bearing tetrasporangia. From September the cystocarpic plants were
observed to decrease in weight, whilst at the same time the tetrasporic
representatives continue to increase in fresh weight, and this appears to
result from the more severe degeneration of the spent cystocarpic
branches compared with those which have borne tetrasporangia. I n
the British Isles this increase in growth rate was found to coincide with
sea temperature increases from 5"-10°C ; growth continues at temperatures of 15"CJ as observed by Causey et ul. (1946) for plants in North
Carolina. I n this case increased growth was observed during spring and
summer, then falling-off in the autumn. Free-living plants showed a
tenfold increase in fresh weight in a period of 14 days during the main
growth period.
Jones (1959a) found the the fruiting cycle showed some correlation with the different phases of growth. Tetrasporangium production commences in spring, reaches its peak in the summer, then
A. D. BONEY
to some disturbance because of their shallow nature, and of low salinity
due to influx of fresh water, e.g. north-east side of Tokyo Bay. Mini0
(1949) described its occurrence in the lagoon of Venice. All evidence
points to the species being able to tolerate a wide range of environmental
conditions.
Very few plants are fertile in Norway and the standing crop is
maintained by vegetative propagation, and regenerative growth was
obtained from fragments 2 mm to 2 cm in length (Stokke, 1957). Such
development, however, was obtained at temperatures between 14"18"CJ and not a t 10°C. Humm (1944) described how free-living Brucilaria plants in the seas offshore in North Carolina showed rapid growth,
and the standing crop formed the basis of an agar industry. Causey
et ul. (1946) showed that growth of Gruciluriu in North Carolina took
place in a temperature range of 1Oo-25"C. I n South Africa the species
is a component of both the cold-water flora on the west coast, and is
also to be found in the warmer seas near Port Elizabeth (Isaac, 1956).
In both these regions the plants grow best in sheltered waters, and the
mean annual temperature range approaches 15°C. Detached fragments
of Gruciluria two inches in length produced new apical and lateral
branches. Jones (1959a) measured the change in weight of both
tetrasporic and cystocarpic plants whilst immersed in the sea, and found
that increase in fresh weight was slow during autumn and winter, and
showed a more noticeable increase in May. This increase in weight was
maintained through June and the rate of change started to slow down
in July and August, and into the autumn. The nature of the growth
process in the tetrasporic and cystocarpic plants appeared to difFer
somewhat, since the increased growth rate was later than with the plants
bearing tetrasporangia. From September the cystocarpic plants were
observed to decrease in weight, whilst at the same time the tetrasporic
representatives continue to increase in fresh weight, and this appears to
result from the more severe degeneration of the spent cystocarpic
branches compared with those which have borne tetrasporangia. I n
the British Isles this increase in growth rate was found to coincide with
sea temperature increases from 5"-10°C ; growth continues at temperatures of 15"CJ as observed by Causey et ul. (1946) for plants in North
Carolina. I n this case increased growth was observed during spring and
summer, then falling-off in the autumn. Free-living plants showed a
tenfold increase in fresh weight in a period of 14 days during the main
growth period.
Jones (1959a) found the the fruiting cycle showed some correlation with the different phases of growth. Tetrasporangium production commences in spring, reaches its peak in the summer, then