1883.] NATURAL SCIENCES OF PHILADELPHIA. 193 



nigra, C. ochroleiica, G. rutifolia, Cirsium serrulatum, G. dis- 

 color, and G. lanceolatum. The motion seems most active when 

 the anthers are ready to shed their pollen, and, as pollen-gathering 

 insects anticipate the observer, it is best to cut the flowers and 

 place them in water in a room. Endeavoring to observe the motion 

 of Girsium discolor in the growing plant almost failed from this 

 cause, but on drawing a light substance over the whole head, some 

 of the florets were found to move. 



In the Gentaurea flowers on the table, the best period for 

 observing the motion is when the anthers which cover the apex 

 of the pistil seem about to allow the pistil to protrude. If then 

 touched, the pollen is seen to issue from the mouth of the united 

 stamens, and the whole crown of anthers to decline. Cohn, above 

 cited, gives the exact measurement of this contraction, and 

 explains the mechanism by which the contraction is accomplished. 

 At the same time, if the motive power be very active, the whole 

 upper portion of the floret, moves in some direction, apparently 

 without order or system. Sometimes it is in a lateral direction, 

 at other times upwards or downwards, and sometimes describing 

 a circle round its own axis. In some cases the motion is commu- 

 nicated to other florets — two and sometimes three moving to the 

 touch of a single one. In ten minutes after the exhibition of 

 irritation, it is ready for another fit, and goes through the motions, 

 though less actively than before. Mr, Meehan had failed to get 

 any motion three times from the same floret, and not always two. 

 Touching the pistil had no effect unless the force was sufficient to 

 press one side against the anther. The irritation seemed to be 

 confined to the stamens, and through these probably down by their 

 nervous connections through the achenium, and in this yvay com- 

 municating with the nerves which run up through neighboring 

 achenes to the stamens which they support. 



Since the above communication was made to the Aeademj'-, 

 Mr, J. H. Redfield believes that the neutral raj' florets in Gen- 

 taurea Americana, which have neither stamens nor pistil, also 

 possess the power of motion, and Miss Powell, without knowledge 

 of Mr.'Redfield's observation, notes a similar experience. 



September 18. 

 Mr. Thomas Meehan, Vice-President, in the chair. 

 Thirty-one persons present. 

 The death of John C. Trautwine, a member, was announced. 



Notes on the Sequoia gigantea.-^M.r. Meehan remarked that so 

 much had been written about the mammoth trees, that there seemed 

 little room for more; but to one of the fullest accounts given, 

 namely, that by Mr. Muir in the Proceedings of the Meeting of 



