424 S[JMMA.RY OF CURRENT RESEARCHES RELA-TING TO 



of pure pectin. In the central tissue, the wall of large hyphte is (a) of 

 pecto-cellulose, surrounded by (b) a, thin pectic envelope having (c) an 

 aureole traversed by radiating pectic filaments ; outside this is (d) the 

 general mucilage. In the frond this mucilage is again slightly pectic, 

 but not at all pectic in the receptacle of Fucus vesiculosus. The small 

 hyphfe have no radiating aureole. The cuticle contains no cutin. 6. 

 Cystoseirese possess no mucilage in the central tissue. In the peripheral 

 stratum the cells show two distinct halves ; in the exterior half is 

 accumulated the fucosan ; in the interior half are the nucleus and 

 phffioplasts. In consequence, the form of the subjacent cells, which 

 arise from the divisions of the peripheral cells, is cubic or even flattened. 

 In the other genera the subjacent cells are more elongated in the same 

 direction as the peripheral cells. 



Germination of Floridese.* — W. Nienburg describes and figures the 

 morphology and structure of the germinating plants of Delesseria rusci- 

 folia and RhodophylUs bifida. In the former case there is a strong 

 resemblance to Nitophyllum punctatum ; the young plant arises direct 

 from the holdfast. In RhodophylUs there is a sort of thalloid protonema- 

 stage intervening, as in some other Florideae. 



Arctic and Antarctic Melobesieae.t — Madame Lemoine gives an 

 account of the general characters of the genera of Arctic and Antarctic 

 Melobesieaj. In the Antarctic region are fourteen species of Litho- 

 thamnium and five of LithophyUiim, while in the Arctic are sixteen 

 species of Lithothamnium. and two of Litkoph?jUum. The polar species 

 of Lithothamnium reseml)le those of the temperate regions ; but in 

 Lithophyllum the polar species are aberrant in structure. In typical 

 LitlwphyUum the hypothallus is composed of concentrically arranged 

 monostromatic fans of cells. Typical Lithophyllum is entirely absent in 

 the Arctic region, and is represented by but one species in the Antarctic 

 ■ — L. rugosum. The polar species of Lithophyllum are aberrant, and are 

 ranged by the author in three groups, the structural characters of which 

 she defines. To one of them she gives the new subgeneric name, 

 Antarcticophyllum. A fourth group she separates off under the new 

 generic name Psendolithophylhiyn, on account of the anatomical charac- 

 ters. Finally, she shows that : — 1. No species is common to the two 

 poles. 2. Pseudolithophyllum ?a\A Antarcticophyllum are not represented 

 in the Arctic region. 3. The Arctic species form well-developed submarine 

 banks, and many of them are ramified ; but the Antarctic species form 

 very thin crusts on rocks, and, with one exception, are not ramified. In 

 both regions epiphytic species are rare, 



Finnish Algas.J — C. Skottsberg writes on a small collection of marine 

 algge from Tviirminne in South-west Finnland. He records a new locality 

 for the very rare minute alga Ascocyclus affinis. He describes and 

 figures the microscopical structure of new forms of Desmotriclmm 

 scopulorum and of Eudesme virescens. He adds critical notes on the 

 other species. 



* Hedwigia. li. (1912) pt>. 299-305 (figs.). 



+ Comptes ilendus, cliv. (1912) pp. 781-4. 



X Act. Soc. pro Faun, et Flor. Fenuica, xxxiv. No. 11 (1911) 18 pp. 



