NOTES AND MEMORANDA. 



Eecent Observations on Botrydium granulatum. — In an 

 iiiterestinfj memoir lately published in the * Botanische 

 Zeitung' (Nos. 41 and 42, 1877) by Profs. J. Rostafinski 

 and M. Woronin, the history of a geo<?raphieally widely 

 difTused, but hitherto not at all understood, little Chloro- 

 phyllaceous alga — Botrydium granulatum — has just been 

 brought to light. The investigations had first been 

 begun by Professor Rostafinski and Count H. zu Solms 

 Laubach in Strassburg. They found, however, that Professor 

 Woronin in Finland was occupied in the same research, 

 and that he had already published some of his results in the 

 ' Natiuforschende Gesellschaft ' in St. Petersburg; subse- 

 quently Count Solms withdrew, and the two other obser- 

 vers completed their investigations in conjunction, and have 

 just published their results. 



After giving an historical r/swm/ of the literature on Botry- 

 dium — from Ray, Uillen, Linnaeus, onwards — the authors 

 ])roceed to describe their observations on its develoj)ment- 

 history. 



Having alluded to its well-known mode of occurrence and 

 the form of this little ])lant, they take up tlie account of its 

 history by describing the zoospores. If a plant be placed 

 in water, its contents become modified at the later part of 

 the day or at night into these. The first indication is the 

 formation of numerous vacuoles in the chloroph) 11-containing 

 parietal stratum of contents, these vacuoles gradually in- 

 creasing in quantity until the latter acquires a reticulate 

 aspect. The wall swells up, which exerts a pressure on the 

 fluid contents, whereby the wall bursts somewhere at the top, 

 and the zoospores, meantime resulting from the division of the 

 parietal stratum, issue forth. If the plant be only moistened 

 — which by no means seldom hajipons in nature — the zoo- 

 spores do not swarm out, but come to rest within the col- 



