K n i g h t , Nuclear Phases and Alternation in Algae. Phaeophyceae.
31
D. H a p l o i d p h a s e s u b o r d i n a t e t o d i p l o i d
in s t a t u r e a n d d u r a t i o n .
(Laminaria type.)
Dictyosiphon foeniculaceus,
Pylaiella littoralis,
Splachnidium rugosum,
Castagnea,
Nereia ?
Sporochnus ?
Aspe.roGoc.cus spp. (sometimes),
Carpomitra ?
Desmarestia ?
Arthrocladia ?
Stilophora ?
Chordaria ?
Myriogloea ?
Mesogloia ?
Elachista fucicola ?
Litosiphon Laminariae ?
E. H a p l o i d p h a s e e l i m i n a t e d , d i p l o i d
dominant.
Myriotrichia clavaeformis,
M. filiformis,
Asperococcus echinatus (commonly in Britain),
A. compressus (commonly in Britain),
A. bullosus (commonly in Britain),
Punctaria latifolia,
Sphacelaria bipinnata,
Stypocaulon scoparium, ;
Ectocarpus siliculosus (commonly in Britain),
E. tomentosus (commonly in Britain),
E. Hincksiae (commonly in Britain),
E. fasiculatus (commonly in Britain),
E. velutinus (commonly in Britain),
Pylaiella littoralis (occasionally),
Scytosiphon lomentarius (sexuality entirely lost, reproduction
by non-sexual zoids only) ?
Haloihrix lumbricalis ?
Litosiphon Laminariae ?
Leathesia difformisl
Myriactis spp. ?
Desmarestia ?
Arthrocladia ?
Spermatochnus ?
Stilophora ?
Scrutiny of the compiled data shews that there is strong
evidence in favour of the view that a life-cycle with two well
marked phases — haploid and diploid — is fundamental for the