112 EXPERIMENT STATION RECORD. 



other liybrid needlings of the same parentage. The hyljrids of the second genera- 

 tion, wliere the seed was inl^red, showed a great loss of vigor, 1)eing small in struc- 

 ture and almost totally sterile. From these observations it is believed that in fixing 

 corn hybrids it will be found desiraVjle to cross different hyljrid sei'dlings of the same 

 parentage which are found to present the same characters, ratlier than inbreed the 

 hybrid with its own pollen, as is frequently advocated by plant breeders. 



The morphology of the fruit of Opuntia, J. W. Toumey {Ahs. hi Scieiire, n. 

 ser., 13 {1901), No. 320, pp. 253, 254)- — While the primary function of fruits is seed 

 production and dissemination, according to the author the Opuntia has developed 

 special adaptations for this purpose. Under the influence of desert environment 

 many species of plants have to a great degree lost the power of production of seed, 

 and in Opuntia fnlgida the fruit is mostly sterile. The reproduction of the plant 

 largely takes place by the dissemination of the swollen, spine-covered, terminal 

 joints. In this case the function of the fruit is not to produce seeds but to attrac;t 

 animals to the plant that the fragile l)ranches may adhere to them and thus become 

 disseminated. In many instances the author has observed clusters of spineless, 

 short, proliferous joints which resemble fruits externally, but are entirely without 

 evidence of even an abortive ovary. These in the economy of plants serve the same 

 purpose as fruit clusters without the necessity of floral development. 



Concerning' manna produced by olive trees, Trabut ( Compt. Rend. Acad. 

 Sci. Paris, 132 {1901), No. 4, pp. 225, 226; Bui. Agr. Algerie et Tunisie, 7 {1901), No. 

 3, pp. 54-56, fig. 1) . — The author reports the occurrence in Algiers of a great number 

 of olive trees which exude during the summer a form of manna which is api)arently 

 identical with that produced by the ash tree. Analysis shows it to contain 52 per 

 cent mannite and 7.8 per cent reducing sugars. The trees producing the manna are 

 evidently diseased. The manna exudes from the trunk and larger l)ranches and at 

 these points the cambium is in a state of complete liquefaction. This decomposition 

 is caused by a bacterium. It forms large canker-like growths, exposing the naked 

 wood. The author is led to believe that the bacteria are distributed by insects 

 which puncture the bark, making it possible for the organism to reach the cambial 

 layer. 



The limits of variation in plants, J. W. Harshberger {Alis. in Science, n. ser., 

 13 {1901), Xu. 320, pp. 251, 252). — The author has made astu<lyof the limits of vari- 

 ation in plants as bearing on the survival of seedlings. It was found that size and 

 shajte of leaves, weight and size of fruits varied in a mathematical ratio. The size, 

 configuration, and ])ersistence of early forms in the case of a number of leaves were 

 noted, and these changes were attributed to hereditary impulse and to the direct 

 influence of the environment, fitting the leaf to utilize the space at its disposal, thus 

 enabling the plant to present the largest amount of leaf surface to the light. 



Phenological observations in Canada in 1899, A. H. Mackay {Froc. and 

 Tram. Nova Scotian Taxi. Sci., 10 {1S99-1U00), No. 2, pp. 303-318). — An account is 

 given of the phenomena accompanying the flowering of 10 species of plants which 

 are distributed over a considerable portion of the country, 18 stations being rej)orted. 

 In addition, the first flowering and fruiting of a large numl)er of i)lants, and the dates 

 of the first appearance of migratory birds are given. The species of ])lants (-(jusid- 

 ered in the first portion of the report were mayflower {Epigirarepcns), blue violet, 

 red maple, dandelion, strawberry, wild red cherry, tall buttercup, service bi'rry or 

 shad bush, apple, and lilac. 



On the nitrogenous products of the seed and the embryo of Liupinus albus, 

 N. J. Wassilieff {Ann. Agron., 27 (1901), No. 2, pp. 81-90). — This is an article 

 translated from the (rernian' by K. Sellicr. 



The insular flora of Mississippi and Louisiana, F. E. Lloyd and !>. M. Tracy 

 {Ahs. in Science, n. ser., 13 {1901), No. 320, p. 253).— This paper deals with tlie 



'Landw. Vers. Stat., 7m (1901), No. 1-2, p. 45. 



