1918.] AGRICULTURAL BOTAlTy. 823 



is to summarize the large amount of Isnowledge recently gained and to corre- 

 late this with that which was available at the time of Lock's summary in 1908 

 <E. S. R., 20, p. G29), in order to show the progress made and to indicate what 

 really is the basis of the Mendelian analysis of Pisum. Thirty-six hereditary 

 factors as recognized and represented are dealt with and the available data 

 are interpreted. 



Biocharacters as separable units of organic structure, H. F. Osbobn (Amer. 

 Nat., 51 (1917), No. 608, pp. U9-456) .—The purpose of this synopsis is said 

 to be to bring together and review some of the noteworthy phenomena of char- 

 acter separability as contrasted with those of interdependence, cooperation, 

 •correlation, and coordination. The author proposes the term biocharacters as 

 the general designation of the character unit in the organism. These are dis- 

 cussed as observed in paleontology, and also in regard to their modes of sepa- 

 rability in heredity, in genesis, and in rate of evolution of forms. 



It is claimed that biocharacters are separable in origin, development, evolu- 

 tion, and heredity. They are separable tlu'ough their many modes of origin 

 from the germ, either saltatory, gradational, or continuous. They have different 

 rates of motion, or velocity, in individual development (ontogeny), exhibiting 

 acceleration or retardation. They have different rates of evolution in different 

 phyla, again exhibiting acceleration or retardation. All the biocharacters coop- 

 erate tlirough different modes of grouping in functional correlation, in compen- 

 sation, and in sex linkage. In the hard parts of the body, while the biocharac- 

 ters of form and proportion may originate through continuity, through saltation, 

 or through minute gi-adations, all the known evolution of proportion biocharac- 

 ters is continuous. In the hard parts the biocharacters of rectigradatious have 

 been observed to originate and develop only through continuity. 



Studies on self-sterility. — I, The behavior of self -sterile plants, E. M. East 

 and .1. B. Park {Genetics, 2 {1911), No. 6, pp. 505-609) .—This investigation and 

 the conclusions therefrom have been limited to the self-sterile species Nicotiana 

 foi-getiana, N. alata, N. glutinosa, and N. angustifoUa bred among themselves, 

 all questions connected with the relation between true self-fertility and self- 

 sterility being considered as constituting a distinct problem. 



The tendency to self-sterility is regarded as inherited, these four species 

 breeding true to the quality. This is expressed in these plants from the begin- 

 ning of the flowering season, though toward its close some self -fertility may be 

 shown, especially in plants exhibiting the effects of adverse environmental 

 conditions. This phenomenon, which is called pseudo self-fertility, is consid- 

 ered as a noninherited fluctuation. Self-sterility, whatever its nature may 

 prove to be, is regarded as only a physiological impediment to self-fertilization. 

 The fact that the waning of the reproductive period affects N. alata and 

 N. glutinosa more markedly than the other two species is regarded as indicating 

 multiple allelomorphism in a fundamental factor, the presence of which Is neces- 

 sary to the development of self-sterility. Cross-sterility, identical in its nature 

 with self-sterility, was found in every population of self-sterile plants tested. 

 Self-sterility behaves as a sporophytic character. Part or all of the individuals 

 resulting from one mating may be fertile with one or both parents. It is stated 

 that if A is sterile with B and C, the last two will be sterile when bred togetlier. 

 A varied series of facts observed in this connection is detailed, with discussion. 



Ecolog-y and physiology of the red mangrove, H. 11. M. Bowman {Proc. 

 Amcr. Phil. Soc, 56 {1917), No. 7, pp. 589-672, pis. 6, figs. S).— This is an account 

 of the discussion of a study carried on since 1915 by the author on the red 

 mangrove, RMzopliora mangle, which is claimed to be a plant of economic 

 importance (E. S. R., 37, p. 821). 

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