Apeil 9, 1909] 



SCIENCE 



595 



of momentum eflfeets in electrical discharge. 

 The angle is now formed as follows: A vertical 

 wire leads downward to the plate-holder. Ita 

 lower end terminates in a pin, the head of which 

 is soldered to the end of the wire, and the point 

 of the pin is just above the cover of the plate- 

 holder. Its distance from the cover can be 

 varied by vertical adjustment. The horizontal 

 wire forming one side of the angle has one end 

 soldered to the vertical wire, thus making a right 

 angle. The distance from this junction to the 

 pin may be varied. Satisfactory operation is ob- 

 obtained when the jimction is midway between 

 the head and the point of the pin. In this way a 

 right angle is formed with a discharge point be- 

 low the vertical wire, and in line with it. Such 

 angle-wires may be coupled with each other by 

 joining either their horizontal or their vertical 

 wires. The results are the same as those an- 

 nounced heretofore.^ But the results are more 

 easily obtained with this arrangement than with 

 the one previously described. 



Professor Nipher also finds that the shadow 

 pictures obtained depend upon the material of 

 the plate-holder. With a cover of paper or thin 

 hard rubber, the presence of electrons is shovsTi 

 by branching discharge lines from the images on 

 the film. Refraction effects are also clearly 

 shown. When the cover is of glass or mica, with 

 black paper, the images are like those formed by 

 X-rays, and no refraction is shown.^ By using a 

 machine of large capacity and by arming a metal 

 plate with many points directed toward a sheet 

 of glass, shadow pictures of larger objects may 

 be obtained. 



W. E. McCouBT, 

 Recording Secretary 



THE TOBEET BOTANICAL CLUB 



The first meeting of the club for 1909 was held 

 at the American Museum of Natural History on 

 January 12, President Rusby in the chair. 



This being the annual meeting, reports were 

 presented by the treasurer, editor, chairman of 

 the field committee and secretary. These were 

 read, accepted and placed on file. 



The following officers were elected for the year 

 1909: 



President — ^Henry Hurd Rusby. 



Vice-presidents — Edward Sandford Burgess and 

 John Hendley Barnhart. 



Secretary — Percy Wilson. 



^ Science, July 14, 1908, and December 4, 1908. 

 ^ Science, February 5, 1909. 



Treasurer — William Mansfield. 



^diior— Marshall Avery Howe. 



Associate Editors — John Hendley Barnhart, 

 Jean Broadhurst, Philip Dowell, Alexander W. 

 Evans, Tracy Elliot Hazen, William Alphonso 

 Murrill, Charles Louis Pollard and Herbert Maule 

 Richards. 



The meeting of the club was held at the Mu- 

 seum of the New York Botanical Garden on Jan- 

 uary 28, President Rusby in the chair. 



The scientific program consisted of two papers, 

 of which the following abstracts were prepared 

 by the authors : 



Studies in the Embryology of the Mistletoe, Den- 



dropemon: Miss Makt M. Beackett. 



This study was made from two species of Lor- 

 anthacese — Dendropemon earibwus, gathered by 

 Professor F. E. Lloyd from lime-trees in Dominica, 

 and Dendropemon parvifolius collected by the 

 writer from the bitter-broom, Baccharis, at Cin- 

 chona, in the Blue Mountains of Jamaica. 



The flowers of Dendropemon are perfect, regular 

 and symmetrical. The buds form in clusters of 

 three in the axils of the leaves, and are protected 

 by bracts. The corolla consists of six petals, 

 which, in D. parvifolius, are of a reddish color on 

 the outside, and a delicate pink within. There are 

 six stamens borne upon an inferior ovary, the 

 three fertile stamens alternating with three sterile 

 stamens. The flower has one style and one stigma. 

 At the top of the ovary is the cup-shaped 

 calyculus. 



At the time that the corolla and stamens ap- 

 pear as rounded knobs, two carpellary leaves meet 

 over a central placenta, forming a cavity. The 

 carpellary and placental tissues gradually unite, 

 filling the cavity. Growth in the length of the 

 pistil begins to be rapid, and the stamens develop. 

 During this time cell-division is going on in the 

 region of the nueellus. There is, however, nothing 

 to mark the development of an ovule as a distinct 

 organ, nor is there any indication of integument. 

 In the center of the ovary the cells increase in 

 number and size and contain large nuclei. They 

 elongate parallel to the main axis, become irregu- 

 lar, and constitute the archesporial tissue. Their 

 growth is accompanied by periclinal division in 

 the adjacent cells. Several large archesporial cells 

 form megaspores; the neighboring cells become 

 disorganized and gradually disintegrate. Appar- 

 ently only one of the megaspores becomes an 

 embryo-sac. 



