N0TE8 ON RECENT KESEAItCII. 517 



tran.sfoniiations which arc usually assumofl to occur, rh steps in the process, 

 do not in reality contribute to a solution of the difhculties of accountin.t^' 

 for the ori^'in of new races. A more complete account of I*iof. Dc \'ri(!s's 

 observations and theories will be found in the first volume (fill as yet 

 published) of his " Die Mutations-theorie : \'ersuch(! uiid lieobnchtnn^'en 

 iiber die Kntstehunf^ von Art(m iiii Pfhui/xmreich," piiblislierl }i,t Lfiipzi^'. 



J. li. F. 



Vl'AAAA. 



Pellia, Nuclear Studies on. By Bradley Mooiv Djivis (Am/. 

 Bol. vol. XV. No. Ivii. p. 148). — The Liverworts, th(i author says, are 

 interesting^ because they ofi'er the possibility of solvinf^ certain problems 

 of f^reat importance to our understandin«^^ of the morf)holo^'y of the 

 plant-cell, and particularly the conditions characteristic of nuclear 

 divisions in the higher plants. His efforts have evidently becjn di reacted 

 to a thorough knowledge of Pellia from this point of view. — U. L L. 



l^IM'MKOMIA. 



Peperomia, Embryo-sac of. By Professor Douglas Houghton 

 Campbell, of California {Ann. Bol. vol. xv. No. Ivii. p. 103). — The 

 author reiterates his opinion that in Peperomia we have the most 

 primitive type of Angiosperm yet described. The most remarkable fact 

 brought out in the study of the embryo-sac, he says, was in the behaviour 

 of the nuclei, which differ remarkably from those of other Angiosperms. 

 The marked polarity of the typical embryo-sac is found entirely wanting, 

 and by further division of the eight nuclei, unique so far as known, there 

 are normally sixteen nuclei in the imfertilised embryo-sac. — /i. /. L. 



Action of Minki{Als. 



Physiolog'ical R61e of Mineral Substances. By M. E. Demoussy 

 {Ann. Aij. p. IU7, July 25, llJOl). —Where lime does not exist the leaves 

 of ]3eetroot are spotted with yellow; mosses do not form spores. 

 rhosplH)ric acid necessary for cellular division and the production of 

 chlorophyll. Iron, although not present in chlorophyll, is necessary for its 

 formation. Iron necessary to the lower fungi. The pollen of Pines 

 contains manganese. Chlorine not useful to vegetation generally, though 

 Buckwheat, which grows well without it up to the flowering period, 

 will not seed without chloride of potash. Chloride of soda, (connnon 

 salt) retards the development of Wheat, also its germination. Fluorine 

 not necessary to plants, (ireen plants require potassium to utilise the 

 hydrates of carbon and albuminoids ; most of the fungi also requin* 

 potassium. Sodium salts do not replace those of potash, but may have 

 beneficial effect in neutralising acids and in osmotic functions. Wheat 

 is sometimes benefited by them. Leaves proportionately contain more 

 lime ; the Howers, roots, bulbs more magnesia. In trees nuignesia 

 increases towards the centre. Lime increases towards the bark. 

 Of the elements — phosphoric acid, potash, magnesia, and lime, the 

 absence of lime makes itself felt before all others. Lime apparently 

 assists in the transport of starch up the stem, in chemical transforma- 



