Mat 27, 1904.] 



SCIENCE. 



825 



purpose of reaching out after food materials, 

 as their size seems to depend on the amount 

 of starch present. This view is rendered 

 somewhat questionable by the phenomena ob- 

 served by Wylie in Elodea, where pollen-tubes 

 may produce similar ' cystoids ' in. the free 

 space of the locule, but never produce them 

 in the tissues where food substances must be 

 more abundant. 



Longo supports his conclusion that the inter- 

 cellular course of the pollen-tube is followed 

 not because of inability to grow in open space, 

 by showing that pollen-tubes may be produced 

 in moist air from such normally endotropic 

 forms as Humulus Lupulus L., Picea excelsa, 

 etc. He interprets chalazogamy as a physio- 

 logical fact having bearing on phylogeny. In 

 plants having endotropic pollen-tubes, he con- 

 siders the direction of their growth to be de- 

 termined chemotactieally. 



The main points in Professor Lloyd's inde- 

 pendent conclusions from work on Eubiacese 

 are: (1) The form of cells in the conductive 

 tissue does not determine the course of the 

 pollen-tube, for id Bichardsonia and Diodia 

 .teres the cells are elongated at right angles 

 ±0 the path of the tube. He believes the 

 chemotactic stimulus which determines the 

 direction to be differentially distributed from 

 the egg cell (2) The ectotropic or endotropic 

 behavior of the pollen-tube is a physiological 

 character. 



The second paper of the evening, by Mr. 

 Edward W. Berry, was entitled ' Some Mono- 

 typic Genera of the Eastern United States and 

 their Ancestors.' The phylogeny of Lirioden- 

 dron was briefly sketched from its first ap- 

 pearance as a narrow simple-leaved form in 

 the mid-Cretaceous of the Atlantic coastal 

 plain, its spread to Europe and Asia, its de- 

 velopment into large lobate leaved forms, and 

 its final extinction except for the existing 

 species of eastern North America and a wan- 

 ing variety in eastern Asia. Drawings of all 

 the fossil species were shown, and numerous 

 blue-prints of the leaves of the existing species, 

 showing their parallelism and range of varia- 

 tion. 



Sassafras was the second genus considered. 

 It was pointed out that while the described 



fossil species were numerous, many of them 

 are not allied to Sassafras. The species which 

 were considered as positively identified were 

 discussed, as well as the peculiar characters 

 of the leaves of the existing species, both an- 

 cient and modern forms being abundantly il- 

 lustrated. 



The third genus discussed was Comptonia. 

 Its former range and develoi^ment were de- 

 scribed and drawings of a number of the 

 species were shown. 



All three genera were considered to have 

 taken their origin from simple-leaved an- 

 cestors which flourished during the closing 

 days of the lower cretaceous, and to have 

 originated in America, becoming dominant 

 and widespread in pre-glacial times, flnally be- 

 coming restricted to their present habitats 

 chiefly through the agency of the glacial con- 

 ditions of the Pleistocene period. 



The paper was discussed by Professors 

 Eusby, Underwood and Lloyd and Dr. Howe. 

 Tracy E. Hazen, 

 Secretary pro tern. 



THE NEW YORK ACADEMY OF SCIENCES. 

 SECTION OF ASTRONOMY, PHYSICS AND CHEMISTRY. 



The regular meeting of the section was held 

 on April 4, at the American Museum of 

 Natural History. The program consisted of 

 three papers, abstracts of which are as follows : 

 The Variation of Latitude at New York City:, 



Part 2, Variation of Latitude hnd Constant 



of Aherration: J. K. Kees, Harold Jacoby 



and Herman S. Davis. 



The results of seven years' continuous ob- 

 servations for a study of latitude variation 

 and the aberration of light are contained in 

 the present paper, which will appear as the 

 second and last part of Vol. 1, in the academy's 

 series of Memoirs. To that publication the 

 reader is referred for complete details and re- 

 sults; it is not possible here to do more than 

 mention very briefly the plan of the work, 

 and to state the fact of its completion. 



The simultaneous and continuous observa- 

 tion of the same stars at stations situated on 

 a single parallel of latitude, but separated 

 widely in longitude, has long been recognized 

 as the best method of attacking the problem 



