172
A. D. BONEY
“ stripes ” of pale coloured cells come to lie between the darker areas, so
producing the effect which is considered a specific character, (resembling also Porphyra leucosticta). During autumn and winter the
following sequence is frequently observed : the plants commence the
reproductive phase bearing only monosporangia, then monosporangia
and spermatangia, then monosporangia, spermatangia and “ carpogonia ”, and finally only sexual organs. Various transitional stages are
to be observed between these main phases. “ Carpospores ” produce
the Conchocelis-phase on germination, but towards the end of the growth
season certain “ abortive ” cells are observed amongst the “ carpogonia ”, and these cells are also seen to produce spores. With such a
protracted period of asexual reproduction, very young plants are found
on the “ hibi ” throughout the greater part of the autumn, winter and
spring. Liberation of spores from the Conchocelis-phase apparently
continues for as long as the sea temperature remains above 10°C. In
Matsushima Bay it was observed that the times of the phasing of the
reproductive stages depended on the position of the ‘ I hibi ”, (e.g.
whether they were situated near the open sea, or close inshore).
The similarity between this species and Porphyra leucosticta was
emphasized by Kurogi, who, nevertheless, left the problem largely.
unresolved ; several forms previously attributed to Porphyra tenera by
workers in the past should in fact be incorporated in P. yezoensis. In
natural habitats the plants of this species are usually found as epiphytes,
showing some degree of seasonal migration over the course of the year.
In these shore habitats the plant appears in greater numbers between
March and May, but in the cultivated areas they appear on the “ hibi ”
from December onwards. The period for harvesting can extend from
December until May.
Porphyra kuniedai. The cultivated laver described as P. kuniedai by
Kurogi (1961) has previously been described as forms of P. tenera and
P. yezoensis; Kurogi has emphasized that there is a close similarity
between this species and P. leucosticta f. mediterranea described by
Hamel (1924). This species shows a longer growth season than any of
the lavers so far described, and may persist for the greater part of the
year. In common with P. tenera it is a component of the “ inner ”
seas of Japan (Kurogi, 1963a).
The plants are rounded or reniform in shape, with a rounded,
cordate or umbilicate basal region ; the margins may be lobed and undulate and the frond deeply cleft. Frond length can reach up to 10 cm,
and the plants are reddish-brown in colour. The plants are monoecious, and the male areas on the frond show a similar sequence of
A. D. BONEY
“ stripes ” of pale coloured cells come to lie between the darker areas, so
producing the effect which is considered a specific character, (resembling also Porphyra leucosticta). During autumn and winter the
following sequence is frequently observed : the plants commence the
reproductive phase bearing only monosporangia, then monosporangia
and spermatangia, then monosporangia, spermatangia and “ carpogonia ”, and finally only sexual organs. Various transitional stages are
to be observed between these main phases. “ Carpospores ” produce
the Conchocelis-phase on germination, but towards the end of the growth
season certain “ abortive ” cells are observed amongst the “ carpogonia ”, and these cells are also seen to produce spores. With such a
protracted period of asexual reproduction, very young plants are found
on the “ hibi ” throughout the greater part of the autumn, winter and
spring. Liberation of spores from the Conchocelis-phase apparently
continues for as long as the sea temperature remains above 10°C. In
Matsushima Bay it was observed that the times of the phasing of the
reproductive stages depended on the position of the ‘ I hibi ”, (e.g.
whether they were situated near the open sea, or close inshore).
The similarity between this species and Porphyra leucosticta was
emphasized by Kurogi, who, nevertheless, left the problem largely.
unresolved ; several forms previously attributed to Porphyra tenera by
workers in the past should in fact be incorporated in P. yezoensis. In
natural habitats the plants of this species are usually found as epiphytes,
showing some degree of seasonal migration over the course of the year.
In these shore habitats the plant appears in greater numbers between
March and May, but in the cultivated areas they appear on the “ hibi ”
from December onwards. The period for harvesting can extend from
December until May.
Porphyra kuniedai. The cultivated laver described as P. kuniedai by
Kurogi (1961) has previously been described as forms of P. tenera and
P. yezoensis; Kurogi has emphasized that there is a close similarity
between this species and P. leucosticta f. mediterranea described by
Hamel (1924). This species shows a longer growth season than any of
the lavers so far described, and may persist for the greater part of the
year. In common with P. tenera it is a component of the “ inner ”
seas of Japan (Kurogi, 1963a).
The plants are rounded or reniform in shape, with a rounded,
cordate or umbilicate basal region ; the margins may be lobed and undulate and the frond deeply cleft. Frond length can reach up to 10 cm,
and the plants are reddish-brown in colour. The plants are monoecious, and the male areas on the frond show a similar sequence of