342 EXPERIMENT STATION EECORD. 



230-232, fi(js. 34). — This is an illustrated series of articles containing numerous 

 observations on hybridizing, crossing, and propagating tropical orchids. The 

 author states that it is a matter of constant occurrence that certain genera and 

 species are found to be capable of greatly affecting, altering, or completely sup- 

 pressing in their progeny the features of the species and genera with which 

 they are crossed. Numerous examples of this occurrence are given. 



The bagging of flowers (Jurfliii. 21 (1907), No. .^86, p. i'/.T). — This is a brief 

 note in regard to the recent experiment of M. Vilaire, of the Rouen botanical 

 garden, on the bagging of lilac blooms. Several blooms scarcely in bud were 

 bagged on March 24 last and came into full bloom on April 26, whereas the 

 check blooms at the latter date showed only buds. These experiments are to 

 be continued with other varieties of flowers. 



A peony check-list, J. E. Coit (Ithaca, N. Y.: N. Y. State Col. Agr., 1901, pp. 

 232, figs. 2). — The author is conducting an extensive peony investigation for 

 the purpose of remedying the existing confusion regarding the names of varie- 

 ties, and of offering simple but comidete and accurate descrijitions of the same. 



The present list comprises the information which has been gathered in con- 

 nection with this work from books, periodicals, manuscripts, etc., and includes 

 the leading varieties of peonies of which authentic descriptions can be found 

 in horticultural literature. The varieties which have been found illustrated, 

 together with the place thereof, and those varieties which may be found in the 

 Cornell plats are all indicated. The list comprises 2,700 varieties and is in- 

 troduced with a description of the Cornell system of alphabetical classification. 

 In conclusion some general lists of varieties reconmiended are given. 



Roses proof against mildew in Australia (Gard. Chron., 3, ser., f/l (1907), 

 ISlo. 10(j5, p. 333). — In this note a list taken from the journal of horticulture 

 of Australia is given of a large number of roses, which are said to be proof 

 against mildew in that country. 



FORESTRY. 



Notes on the radial increment of tree trunks, O. Lignier (Bid. *S'oc. Linn. 

 Noniiaiiilic, ,'>. .ser., 9 (190'>), pp. lSl-22'i). — The author made studies of cross- 

 sections of several species of trees belonging to the botanical collection at 

 Caen, for the purpose of determining whether a satisfactory formula could be 

 derived for computing the age of trees with the aid of the circumference. The 

 results of these studies are discussed in detail, and the data obtained from 

 each species with reference to its yearly-growth increment are presented in 

 tabular form. 



The more important general conclusions derived from this work are, in sub- 

 stance, as follows : The life of a tree may be divided into 2 periods, whic-h vary 

 according to the species. During the first period, or period of acceleration, the 

 thickness of the annual rings increases from year to year. During the second 

 period, or period of abatement, the thickness of the annual rings diminishes 

 progressively, although in this latter period there is an intermediate phase in 

 which the difference is hardly perceptible, a second phase in which the thick- 

 ness decreases consistently, and a third phase in which the change again be- 

 comes slow. The age of the tree can not be correctly obtained by dividing the 

 .radius or diameter of the tree by an average annual growth measurement, but 

 the growth rings must be actually counted. Where an attempt is made to esti- 

 mate the age from the circumference, the measurement should be made at a 

 distance of about 1.8 meters from the ground. 



In the case of Taxus, it was noted that certain annual layers did not extend 

 completely around the tree. With the same species it was found that as the 



