546 SUMMARY OF CUKRENT RESEARCHES RELATING TO 



gutt(i-s will contain as little organic matter as possible, so that only 

 alg£e and no fungi will be able to thrive in them. 



2. But as this is only possible for a short space of time, all dam- 

 ming up of the stream must be avoided so as to allow moulds the 

 opportunity of arresting the too great development of Schizomycetes. 



3. As the Schizomycetes are most rapidly developed in the 

 summer months that is the season requiring the greatest precautions. 



Formation of Tetraspores.* — In the general account of the 

 Floiideai in the first part of the second vol. of Kabenhorst's ' Crypto- 

 gamic Flora of Germany,' &c., F. Hauck states that the dense and 

 highly coloured protoplasmic contents of the tetrasporangia may divide 

 into the four (rarely more or fewer) tetraspores in the six following 

 ways, viz. :— (1) Tetrasporaugium undivided, only one spore being 

 formed from its contents. (2) Bijiartite ; the contents divided into 

 two equal parts by a transverse wall. (3) Divided crosswise ; the 

 contents dividing into quadrants by two successive bipartitions. (4) 

 Tetrahedral division ; the contents dividing into tetrahedra by simul- 

 taneous quadri partition. (5) Zonal division; the contents dividing 

 into four- parts by parallel walls. (6) Multipartite ; when the contents 

 divide into more than four parts. 



Reproduction of Porphyra.t — The systematic position of the 

 Porphyracefe (Porphijra and Ban(iia) has long been a matter of 

 doubt with algologists. In Eabenhorst's new ' Cryptogamic Flora of 

 Germany,' &c., F. Hauck assigns them a definite place as the lowest 

 family of Florideae, and describes the cystocarps (in Porphyra 

 leucosticta) as produced by fecundation by means of a rudimentary 

 trichogyne out of female cells similar in form to the tetraspores, the 

 protoplasm of which divides mostly into four carpospores by division- 

 walls both parallel and vertical to the surface of the thallus. The 

 antheridia and antberozoids are also described. 



Cryptogamic Flora of Arctic Ice and Snow.:}: — V. B. Wittrock 

 describes the cryptogamic vegetation brought from a number of 

 localities within the Arctic zone. The flora of the hard blue ice of 

 the glaciers and of the Greenland inland ice is quite different from 

 that of the eternal snow and of the snow-covered portions of the 

 glaciers. The snow-flora comprises about 40 s^iecies and varieties, 

 the ice-flora only about 10. 



The plant-forms of the snow-flora belong to mosses and algae ; but 

 the former exist only in the protonema form, and can therefore not 

 be determined specifically. The alga3 belong to 8 families and the 

 following 25 genera : — Chroococcus, Gloeocapm, Oscillaria, Scytonema, 

 Stigonema, Navicula, Stauroneifi {'^), Penium, Cijlindroajslis, Chionopkila 

 n. gen., Docidium, Telmemorus, Cosmarium, Euastrum, Staurastrum, 



» Kabenhorst's 'Kiyptogainen-Floi-a YOU Deutsclilai id,' &c. 1882. 2er Band : 

 Die Meeresalgen, von ¥. Hauck,' p. 11. 



t Ibid., p. 25. 



X " Oui SniJns ocli Isens Flora, Siirskildt i de Arktiska Trakttrna." Af Veit 

 Brecber Wittrock. Ur " A. E. Nordenskjold, Studi.;r oi-h fordkuingar foranledda 

 af ruiria resor i boga Noickn." Stockholm, 1883 (2 fig:^. and 5 pis.). Cut. 

 Gesell. Stockholiu. Marcli 7. 1883. See Dot. (Jeutralbl , xiv. (1883) i>. 155. 



