226 EXPERIMENT STATION RECORD. 



tlio c-oiulucting I'leineiUs of the iiiai»lt' nnd popltir trees during tliolr active 

 traiisi)iratioii. Tlie same was shown i)y direct uieasuremeuts of tbe pressure 

 iu vessels of wistaria. Tliis fact, coupled with the high total resistance to flow, 

 shows that this resistance is overcome locally from point to point, and not by 

 any enormous tension from above or pressure from below, neither of which 

 exists nor could be maintained to a sufficient extent to carry on the elevation of 

 water in a tall tree. 



The apparent differences of osmotic pressure previously observed between' 

 leaves at the base and apex of a tall tree it is claimed are not evidences of 

 the existence of any greater osmotic suction at the higher level, but are the 

 result of the different ages and sizes of the cells and the different conditions to 

 which they have been exposed. 



Observations regarding the constancy of mutants and questions regard- 

 ing the origin of disease resistance in plants, H. L, Bolley (Amer. Nat., Jt2 

 (J 908), No. 495, pp. 111-183). — This is a paper read before the American 

 Breeders' Association at its meeting in January, 1908, in which the author gives 

 his views regarding the constancy of a number of mutating forms of plants, and 

 also outlines the i-esults of his investigations on the resistance to disease of 

 various plants with which he has been experimenting. 



The author, in summarizing his results, asserts "(1) that mutants may be so 

 insignificant and numerous as to be unrecognizable and thus fall directly into 

 the class called by DeVries 'fluctuating variations;' or (2) that they may be 

 induced in a mixture of a great number of varieties of a species at one and the 

 same time because of the same environmental causes; or (3) that, in some cases, 

 'fluctuating variations' are of such nature and worth as to allow results to be 

 obtained in mass breeding of as great importance as any that may be hoped to 

 be obtained by looking for a single mutating type." 



In regard to disease resistance the author, while not ready to affirm definitely 

 his position in the matter, believes tliat the resistance is physiological rather 

 than structural. 



The correlation of flower and fruit structure in Carica papaya, P. J. 

 Wester {Bid. Torrcij Hot. Club, 35 {1908), Xo. 3. pp. J ',1-1. ',6. fifjs. 2).— A study 

 has been made of the papaya {C. pupiiya) to determine whether the develop- 

 ment and formation of the fruit might be correlated with the structure of the 

 flower. In this study notes were taken on a number of flowers on the same 

 tree.' The plant is normally dioecious, but rarely produces perfect flowers. In 

 most instances the bisexual flower buds were bagged with small paper sacks, 

 the sack remaining until the flower had faded and the ovary was beginning to 

 develop. 



There was found to l)e a distinct correlation between the formation and size 

 of the fruit and the flower characters. Where the ovary was small and slender, 

 with rays in the stigma nearly aborted, the fruits grew comparatively small, 

 cylindrical, almost solid, with exceedingly small seed cavity containing few 

 seeds; while where the pistil was normal, or nearly so. the fruit grew large, 

 more or less angular, with the apical end distended, and the cavitj' containing 

 a large number of seeds. 



The author thinks the form with small slender ovaries to be preferable, as it 

 yields a fruit that is much more easily packed. Under the usual methods of 

 propagation a large production of seedlings is not considered profitable, and an 

 attemi)t to originate a variety of papaya would probably necessitate hand polli- 

 nation, inbreeding, and rigid selection for several generations. 



The nectaries of cotton, F. J. Tylek ( f '. S. Dcpt. .[(jr.. Bur. Plant IikIk.s, 

 BhJ. 131, pp. .'fo-o.'i, pi. 1). — A study has been made of the nectaries occurring 



