146
A. D. BONEY
forms of the ecad have been described. The potentialities for commercialexploitation of this free-living form of Ascophyllum have not been
fully explored, and more information on the speed of recuperation
after harvesting is necessary.
. 4. Hijikia fusiforme
This is a member of the order Fucales which is utilized as a source
of food in Japan. The plants are compact and cone-like, and built on
a radial plan. The plants show an annual growth of erect fronds which
grow from prostrate " rhizome "-like branches. The young buds appear
in the autumn, and growth and formation of new rhizome tissue
proceeds throughout the winter. Receptacle development proceeds
throughout the winter, and the mature conceptacles shed the eggs and
spermatozoids in the spring. This is followed by defoliation of the spent
receptacles and some of the erect frondage during the summer months,
but the rhizomes are perennial structures. This cycle of events has
been watched over a period of 5 years, and the erect frondage (or
" bush ") can reach a length of 100 cm, and about a kilogram in weight
(Suto, 1951b). Yendo (1907) described different forms of the plant from
the northern and southern seas of Japan.
The plants grow on rocks near low water mark, and reach maximum
development in April. Thereafter there is marked defoliation in the
following summer months. Receptacle development commences in the
winter months, but fertile plants are rarely seen before late spring
(May). Yendo (1907) stated that fertile plants were rare in some parts
of Japan because of the severe defoliation and depopulation seen in
the summer months. If plants survive the summer they may subsequently reach lengths of 6 to 8 f t in sheltered habitats. Suto (1951a)
reported a periodic shedding of the eggs at 7-8 day intervals in May
with sea temperatures in the range of 19"-2OoC, and this continued
until July. The majority of eggs are released at flood tide, and fertilization takes place whilst the eggs are attached to the parent plant.
Initial development of the embryo is accomplished within 24 h of
fertilization, at which time the mucilaginous coat dissolves and the
embryo is shed into the water. Fixation is then rapidly achieved.
According to Chapman (1950), plants can be harvested from January
until May, but the best crops are obtained in January and February
when the fronds are young and tender.
5. Sargassum
Sargassum species are conspicuous elements of the flora of southern
seas, but their morphological complexity and uncertain specific limits
A. D. BONEY
forms of the ecad have been described. The potentialities for commercialexploitation of this free-living form of Ascophyllum have not been
fully explored, and more information on the speed of recuperation
after harvesting is necessary.
. 4. Hijikia fusiforme
This is a member of the order Fucales which is utilized as a source
of food in Japan. The plants are compact and cone-like, and built on
a radial plan. The plants show an annual growth of erect fronds which
grow from prostrate " rhizome "-like branches. The young buds appear
in the autumn, and growth and formation of new rhizome tissue
proceeds throughout the winter. Receptacle development proceeds
throughout the winter, and the mature conceptacles shed the eggs and
spermatozoids in the spring. This is followed by defoliation of the spent
receptacles and some of the erect frondage during the summer months,
but the rhizomes are perennial structures. This cycle of events has
been watched over a period of 5 years, and the erect frondage (or
" bush ") can reach a length of 100 cm, and about a kilogram in weight
(Suto, 1951b). Yendo (1907) described different forms of the plant from
the northern and southern seas of Japan.
The plants grow on rocks near low water mark, and reach maximum
development in April. Thereafter there is marked defoliation in the
following summer months. Receptacle development commences in the
winter months, but fertile plants are rarely seen before late spring
(May). Yendo (1907) stated that fertile plants were rare in some parts
of Japan because of the severe defoliation and depopulation seen in
the summer months. If plants survive the summer they may subsequently reach lengths of 6 to 8 f t in sheltered habitats. Suto (1951a)
reported a periodic shedding of the eggs at 7-8 day intervals in May
with sea temperatures in the range of 19"-2OoC, and this continued
until July. The majority of eggs are released at flood tide, and fertilization takes place whilst the eggs are attached to the parent plant.
Initial development of the embryo is accomplished within 24 h of
fertilization, at which time the mucilaginous coat dissolves and the
embryo is shed into the water. Fixation is then rapidly achieved.
According to Chapman (1950), plants can be harvested from January
until May, but the best crops are obtained in January and February
when the fronds are young and tender.
5. Sargassum
Sargassum species are conspicuous elements of the flora of southern
seas, but their morphological complexity and uncertain specific limits