616 EXPERIMENT STATION EECORD. 



cc. of this solution is removed and tested as above, comparisons being 

 made as already indicated. It is stated tliat tannin is the only sub- 

 stance tliat is liable to cause confused results, and on this account the 

 use of mineral acids is to be avoided in soaking the leaves. 



The author tested 25 species of plants, and 18 gave results indicating 

 the presence of hydrogen peroxid, as follows: Brassica asperifolia, B. 

 oleifera, Dancus earota, Beta vulgaris, Geranium rotundifoJium, Hedera 

 helix, Aster, Tropicolum pentaphyllum. Chrysanthemum halsamita, Mer- 

 curialis annua, Urtica, Caltha palustris, Vicia faba, Fapaver rhceas, 

 Sijsimbrium nasturtium, Bianthus caryoplnjUus, Apium petroselinum, and 

 Fragaria vesca. Two species gave doubtful results, Lactuca sativa and 

 Vicia sp., and 5 gave negative results, as follows: Medicago sativa, 

 Cichorium intyhus, Aven^ sativa, Viola odorata, and Lilium hulhiferum. 

 These experiments show the presence in the green parts of many plants 

 of hydrogen peroxid or peroxids capable of acting as such. 



Investigations of the root tubercles on leguminous plants, W. 

 Wilson {Agl. ^ci., 8 {1894), No. 0-9, ^jp. 437-139).— The autlior, in a let- 

 ter from Aberdeen, Scotland, gives as the results of his observations 

 the conclusion "that leguminous plants produce tubercles most abun- 

 dantly where the conditions are iavorable for the growth of the plants 

 themselves, and not where the plants must struggle for their existence." 

 He finds tubercles very abundant on Cytisus scoparius where the plant 

 grows luxuriantly, while on the roots of plants growing on hillsides 

 there will be few or none. In the case of Genista angliea tubercles are 

 produced in abundance on dry moor plants, while those growing in bet- 

 ter soil are almost wholly without them. JJlex europeus in poor soil will 

 l)roduce abuiulant tubercles, and the author thinks its value for restoring 

 thin soil is due to this fact. The author states that red clover will not 

 produce tubercles if grown in a climate too cold for the plant to mature 

 its seed. He thinks that the failure to grow the \mi[)Voxed Lathyrus 

 sylvestris is due to the specific bacteria required for tubercle formation 

 not being found beyond the limits where the plant finds congenial con- 

 ditions for its growth and development. 



A comparison between the same species of plants in the Arc- 

 tics and Alps, G-. Bonnier {Rev. gen. Bot., (J {1894), JVo. 72, pp. 505-527, 

 pis. 4). — The author has made a comparative histological study of si^eci- 

 mensof Silene acaule, Oxyria digyna, ISaxifraga oppositifolia, Salix retic- 

 ulata, Cerastium alpinnm, Potentilla nivea, and Poapratensis. Compar- 

 ing the Arctic with the Alpine plants he finds that the former difier (1) 

 in the tendency to a reduction in number of the lignified elements in the 

 different parts of the plant, their walls being less thickened and having a 

 smaller caliber of their vessels ; (2) the leaves are more thickened but less 

 differentiated, the palisade parenchyma is less marked and the intercel- 

 lular spaces are greater: (3) the epidermis of the leaves and stems is less 

 coherent and its cuticle less thickened; and (4) all the tissues, leaf, 

 stem, and root, show a tendency to rounder cells, separating greater 

 intercellular s^jaces. 



