434 EXPERIMENT STATION RECORD. [Vol.37 



Root cutting's, chimeras, and sports, W. Bateson {Jour. Genetics, 6 {1916), 

 No. 2, pp. 15-SO, pi. 1). — The author states that some unsuspected plants are 

 really periclinal chimeras, having an outer layer or cortex distinct in genetic 

 composition from the inner core, and that whenever plants grown from root 

 cuttings differ from those grown from corresponding stem cuttings, it may be 

 inferred, at least provisionally, that the plant is a periclinal chimera. Some 

 studies have been undertaken and are still in progress with Bouvardia, some 

 doubles of which are said to give singles from their root cuttings, differences 

 in color appearing also in several instances. 



Fasciation in Pharbitis hederacea, Y. Yamaguchi (Jour. Col. Set., Imp. 

 Univ. Tokyo, S9 {1916), Art. 2, pp. 56, pis. 2, figs. 5).— The author, reporting 

 a study of P. hederacea, states that Ivnop's solution in 1. 2, and particularly 5 

 per cent strength favored the production of fasciation. The higher concentra- 

 tions hindered greatly the development of the fasciated plants, while the normal 

 plants were but little retarded thereby. Darkness had little effect upon the 

 development of fasciation and topping produced no fasciation in normal plants. 

 Longitudinal splitting at the top of the stem resulted in slight fasciation, as 

 did removal of the blooms, the same treatment giving uncertain results when 

 applied to the leaves and tending to recovery of fasciated plants when applied 

 to the roots. 



The woody structure was looser and less developed in fasciated plants, with 

 a relatively greater development of the vascular bundles and a diminution of 

 size with increase in length of the cells. This phenomenon appears to be 

 hereditary, showing from the earliest stage-s. The production of fasciation. so 

 far as its mechanical phases are concerned, is due to the early coalescence of 

 the leaf stalk with the plant stem in conjunction with leaf growth in the early 

 stages of development. 



Plant succession. — An analysis of the development of vegetation, F. E. 

 Clements {Carnegie Inst. Washington Pub. 2.i2 {1916), pp. XII I +512, pis. 61, 

 figs. 51; rev. in Jour, Ecology, 1, {1916), Ao. 5-.^, pp. 198-20Jk) .—This book con- 

 stitutes the general part of a monograph on Rocky Mountain vegetation, a study 

 of which has been In progress since 1809. The general principles herein set 

 forth are an out^rrowth of the treatment in the contributions previously noted 

 (E. S. R., 15, p. 955; 19, p. 529), the original concepts in which have been con- 

 firmed and generalized by the studies since carried on. 



It is thought that the earlier concept of the formation as a complex organ- 

 ism with a characteristic development and structure in harmony with n imr- 

 ticular habitat is fully justified, representing really the only possible complete 

 and adequate view of vegetation. This concept has been broadened aua deh- 

 nitized by the recognition of the developmental unity of the habitat, so that 

 formation and habitat are regarded as the two inseparable phases of a de- 

 velopment which terminates in a climax controlled by climate. All vegetation 

 has thus been developmentally related, everj' climax formation having its 

 phylogeny as well as its ontogeny. Essentially the same processes or func- 

 tions of vegetation have held throughout geologic time, so that it is possible 

 to sketch the succession of plant populations throughout eras and periods, or- 

 ganizing in a tentative fashion the new field of paleoecologj'. 



A bibliography is appended. 



Polar bear cacti. O. F. Cook and Alice C. Cook {Jour. Heredity, 8 (1917), 

 No. 3, pp. llS-120, figs. 6). — Opuntia floecosa, found on exposed slopes of the 

 bleak plateaus of the Andes of southern Peru, is described in connection with 

 environmental relations as regards protection against direct sunshine and cold. 

 It Is suggested that there may be a real analogj- between these cacti and the 



