M. Masuda et K. Kogame, CROSSABILITY BETWEEN HAWAIIAN AND JAPANESE POPULATIONS OF AHNFELTIOPSIS-CONCINNA (GIGARTINALES, RHODOPHYTA), Botanica marina, 41(3), 1998, pp. 243-247
Hawaiian and Japanese populations of the red alga Ahnfeltiopsis concin
na (J. Agardh) Silva et DeCew (Phyllophoraceae, Gigartinales) were exa
mined on the basis of cultured plants. Reported differences between Ha
waiian and Japanese plants in two taxonomically significant reproducti
ve features, the absence or presence of a sterile lateral on the carpo
gonial branch and the non-nemathecial or nemathecial tetrasporangial s
orus, were not found. Plants of both populations formed procarps, each
of which consisted of a large supporting cell and a three-celled carp
ogonial branch (carpogonium, hypogynous cell, and basal cell) with a o
ne-celled sterile lateral from the basal cell, and nemathecial tetrasp
orangial sori. Furthermore, no morphological differences between cultu
red plants of the Hawaiian and Japanese populations were found. All at
tempted crosses were positive, with carpospores from the cross develop
ing into fertile F-1 tetrasporophytes releasing tetraspores that devel
oped into dioecious F-1 gametophytes, the female gametophytes of which
formed normal cystocarps, indicating that interbreeding is potentiall
y free among the populations studied. It is concluded that the Hawaiia
n and Japanese plants are referred to as a single species that shows r
emarkable variability in gross morphology which may be caused by growt
h stages and different environments.