80 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Additions to the Study of Oceanic Algology (Florideae). — 
Angelo Mazza ( Nuovct Notarisia , 1921, 32 , 73-132). The structure of 
typical species of the following genera is described : — Hypnea (4 species) ; 
Fauchea (4 and a variety) ; Gloioderma (1) ; Rhodymenia , Epymenia (1) ; 
Erythrymenia (1) ; Sebdenia (1) ; Lomentaria , Plocamium (3 sub-genera — 
Plocamium , Thamnocarpus , Thamnophora — and 4 species) ; Halo- 
saccion (1). The systematic position of the genus Erythrymenia Schmitz 
has still to be decided ; the name is not to be found in l)e Toni’s 
“ Sylloge Algarum,” nor in the “ Pflanzenfamilien ” of Engler. It 
represents a South African alga, E. obovata Schmitz, found by Dr. H. 
Becker at the Kowie, and named by Prof. Schmitz j ust before his death. 
It appears to belong to the Rhodymeniacese. A. G. 
Monospores of Helminthora divaricata, with a Note on the 
Binuclear Carpogonium. — N. Svedelius (Ber. Deutsch. Bot. Gesell ., 
1917, 35 , 212-24; see also Bot. Centralbl., 1919, 140 , 163). The 
material examined was collected at Rovigno. The species is monoecious 
and lacks the tetraspores. Monospores rich in protoplasm are formed at 
the termination of the filament, often associated with a hair. It would 
almost appear sometimes as if two sporangia were formed successively, 
but so far this remains unproved. The monospores resemble carpospores, 
and they possess amoeboid movement. On germination a creeping 
filament is formed ; the spore itself remains empty and undivided, 
and does not pass into the tissue. The carpogonium is, at the very 
least during a short phase of development, binuclear, in contrast to 
other observations previously made on this species. The entrance 
of the second nucleus into the trichogyne could not however be demon- 
strated. E. S. G. 
Biological Observations on Polysiphonia fastigiata Grev. — 
C. Sauvageau (Rec. trav. bot. neerland., 1921, 18 , 213-30). After a 
short survey of past work on this alga, the author describes his own 
investigations of material growing on Ascophyllum nodosum , Fucus 
vesiculosus and F. platy carpus. Germination, which proceeds similarly 
in both carpospores and tetraspores, is described and figured both under 
natural conditions and under artificial culture. The alga is shown to be 
parasitic and not epiphytic ; its rhizoids take on the character of endophytic 
suckers. Although P. fastigiata is provided with chromatophores, it 
certainly derives part of its sustenance from its host, as is proved by 
the production of adventitious branches exclusively in the immediate 
neighbourhood of the suckers. The limitation of its occurrence — namely, 
on Ascophyllum and Fucus only — is explained by the adaptation of the 
plant to a parasitic life. It occurs less frequently on Fucus than on 
Ascophyllum , although its rhizoids penetrate the cuticle of both without 
difficulty ; it also grows less luxuriantly ou the former host. These 
facts would indicate a less satisfactory nutrition from Fucus. The 
sucker is directed on the host by chemiotropism, not by negative photo- 
tropism. Notwithstanding its constant parasitism in nature, its spores 
germinate easily in cultures, on glass slides, and produce plantlets. 
E. S. G. 
