No. 2, September, 1921] GENETICS 113 



of wood. Trees over 40 cm. in diameter usually have no future value because for larger trees 

 b is negative, making the sum of a + 6 less than c. The great and definitely known increase 

 in price during the last seven years, however, gives a positive future value to trees up to GO 

 era. in diameter. In the case of young oak standards for this period c amounts to 15 per cent, 

 to which may be added 2 per cent for current annual volume growth (a), making a total of 

 17 per cent even if b is ignored entirely. — S. T. Dana. 



725. Sammereyer, Hans. Zirbenkulturen. [Swiss stone pine (P. cembra) culture.] 

 Wiener Allg. Forst- u. Jagd Zeitg. 38: 332-333. 1920. — Pinus cembra has good possibilities 

 for planting in the Tyrol region. The wood is in high demand for charcoal in local smeleters 

 and manj^ high mountain forests have been devastated on account of this demand. Toward the 

 upper range of fir and larch it is often difficult to get successful plantations, but the establish- 

 ment of Swiss stone pine is easy, and larch and fir are later introduced with ease, — the stone 

 pine is choked out in a few years. The real field of usefulness of the species is at higher eleva- 

 tions (above 1800 meters), where it is virtually the only species that develops rapidly. Plant- 

 ing is much superior to sowing on account of the abundance of rodents and birds which destroy 

 the seed; but in exceedingly rocky sites a combination of sowing and planting seems best as 

 seedlings can establish themselves among the rocks where holes cannot be dug. While this 

 species succeeds in the open, it does much better in the protection of rocks, hummocks, and 

 old stumps. Four to 6 year old seedling stock, as a rule raised in nurseries near the planting 

 site, is generally used. Rodents and jays are the chief enemies of such nurseries; the former 

 are combatted by the use of typhus bacilli, the latter by wooden lattice work over the beds. — 

 F. S. Baker. 



726. Sim, T. R. Timber trees for commercial culture. South African Jour. Indust. 3: 

 10.30-1039. 1920. — A list is presented of trees that have been tried in Natal, with notes on 

 success or failure. — A. J. Pieters. 



121 . Vestergaard, N. Dansk Skovforenings Opvisning af Skovmaskiner og Redskaber 

 i Haslev-Omed Skov den 17. April 1920. [Demonstration of machinery for use in forestry 

 operations at Haslev-Omed forest April 17, 1920. Under auspicies of the Danish forestry 

 association.] Dansk Skovforenings Tidsskr. 5: 231-247. PL 13. 1920. 



728. Weir, James R. The mucilage of mistletoe berries as an adhesive. Phytopathology 

 11: 99. 1921. — A method is given for the preparation of mucilage from the berries of Phora- 

 dcndron, Viscum, and related genera. — B. B. Higgins. 



GENETICS 



George H. Shull, Editor 

 James P. Kelly, Assistant Editor 



(See also in this issue Entries 587, 594, 596, 598, 603, 613, 617, 627, 630, 639, 647, 685, 695, 

 697, 785, 789, 792, 807, 816, 823, 832, 840, 851, 871, 876, 941, 1100) 



729. Anonymous. Mutations and evolution. [Rev. of: Gates, R. Mutations and evo- 

 lution. New Phytol. 19: 26-34, 64-88, 132-151, 172-188, 213-253. 1920.] Nature 107: 636- 

 637. 1921. 



730. Anonymous. The pollination of Incarvilleas. [Rev. of: Cutting, E. M. On the 

 pollination mechanism of Incarvillea Delavayi, Franch. Ann. Botany 35: 63-71. 3 fig. 1921.] 

 Gard. Chron. 69: 97. 1921. 



731. Agar, W. E. Cytology with special reference to the metazoan nucleus, xii + 22^ p. 

 Macmillan & Co. : New York and London, 1920. — A condensed general treatise on the subject 

 indicated by the title is presented. The author contrasts parasyndesis and telosyndesis, 



