«08 



SCIENCE 



[N. S. Vol. XXXI. No. 



<5eometria noneuclidea and Liebmann's Ger- 

 man translation, by Arthur Eanum; Nichol's 

 Analytic geometry, revised edition, andWent- 

 •worth and Smith's Complete arithmetic, by 

 G. H. Scott; Wangerin's Theorie des Poten- 

 tials und der KugeKunktionen, by J. B. 

 Shaw; Timerding's Geometrie der Krafte, by 

 W. E. Longley ; " Notes " ; " New Publica- 

 tions." 



BOTANICAL NOTES 



FORESTS AS GATHERERS OF NITROGEN 



At a meeting of the Society of American 

 Toresters, on March 31, 1910, a paper was 

 read by Mr. Treadwell Cleveland, Jr., on 

 " Forests as Gatherers of Nitrogen." This 

 paper summarized results recently obtained 

 by Jamieson, of Scotland, and by Zemplen 

 and Eoth, of the Eoyal Hungarian Experi- 

 ment Station at Selmecbanya, which tend to 

 show that forests are able to appropriate free 

 atmospheric nitrogen by means of their 

 trichomes. Jamieson investigated several 

 forest trees (as well as a number of smaller 

 plants), among which were Acer campestre, 

 Tilia europaea, Ulmus campestris, Sorbus 

 aucuparia, Fagus silvatica and Picea con- 

 color. Zemplen and Eoth included a large 

 number of additional species. In all cases 

 chemical tests show the presence of nitrogen 

 in the trichomes, and the investigators be- 

 lieve that they have excluded all other sources 

 for this nitrogen than the atmosphere. Pro- 

 fessor Henry, of the Forest School at Nancy, 

 France, was the first to point out that forest 

 soils are enriched in nitrogen by the decay of 

 fallen leaves. 



Zemplen and Eoth are cautious in their 

 conclusions, and urge that further investiga- 

 tions be made in this field. 



A STUDY OF PEAT-BOG FLORAS 



In the last Eeport of the Iowa Geological 

 Survey Professor L. H. Pammel discusses the 

 peat flora found in the swamps and marshes 

 of Iowa. For the bog formations he follows 

 C. A. Davis's monograph. These bogs are not 

 of the Sphagnum type usually associated 



with the term, but are listed by the author as 

 follows: Quaking aspen bog, willow bog, 

 grass and sedge marshes, rush marshes, moss 

 bogs. The bog floras of Iowa, Wisconsin, 

 southern Michigan and the Dismal Swamp 

 Virginia are compared from a list of three 

 hundred or more plants, showing strikingly 

 the differences in their constitution. 



The following observations may be noted. 

 Sphagnum, Larix laricina. Thuya occiden- 

 talis and Picea mariana are not found in the 

 state. Heaths are absent from the swamp 

 flora. Of the fifteen plants listed by Tran- 

 seau as characteristic of the bogs of northern 

 America only five are found in the bogs of 

 Iowa. Certain plants common to the peat 

 bogs of regions farther north are not in the 

 bogs of Iowa but are found in the colder and 

 less fertile locations. Carex filiformis is the 

 best peat former in the state. 



The author discusses the important contri- 

 butions to the subject, and gives a bibliog- 

 raphy. 



THE PRINCIPLE OF HOMOEOSIS 



About a year ago Professor E. G. Leavitt 

 published (Bot. Gaz., January, 1909) a paper 

 entitled " A Vegetative Mutant and the 

 Principle of Homoeosis in Plants," which 

 has not received the attention it deserves at 

 the hands of botanists, no doubt partly due 

 to the fact that it was not fuUy understood, 

 and also that botanists, as a rule, are not 

 greatly interested in underlying principles. 

 They are so busy with the collection of solid 

 facts of one kind and another that such 

 " vague and insubstantial " things as prin- 

 ciples have little attraction for them. This 

 may account for the assertion made by a well- 

 known professor of philosophy in a gathering 

 of botanists a few years ago, namely, that 

 " while botany has had many eminent men, it 

 has been singularly unproductive in giving 

 to the world any conspicuous general prin- 

 ciples." Be this as it may, the fact remains 

 that scant attention has been given to the 

 paper here referred to, and to the principle 

 which it sets forth. 



Beginning with some familiar cases of leaf 

 abscission, and of the decompounding of 



