54 



BOTANICAL GAZETTE 



[JANUARY 



In order to determine the individual variations of plants taken at the same 

 time of year and treated in exactly the same way, the following species were 

 studied with appended results : 



April, 5 plants Pelargonium zonale, .620, .645, .767, .782, 1.035 atmospheres. 

 June, 5 plants Fuchsia speciosa, 1.406, 1.428, 1.467, 1.500, 1.605 



Wliile an average of the pressures given by the above plants may seem 



of no great value, nevertheless there is a certain advantage in knowing this 



mean, which may be taken as a general expression of the root pressure of 



common greenhouse plants. The mean pressure of the 22 plants studied 



is approximately o . 9 atmosphere, or in round numbers if' for the square 

 inch. 



Turning from pressure to quantity of exudation, the above table shows 

 that the plants giving the greatest quantity of exudation are Fuchsia speciosa 

 and Begoni<i coccinea. Different plants of Fm:hsia speciosa vary greatly 

 in the quantity given off, and this seems to be correlated with the formation 

 of new shoots— the longer this is delayed the greater the flow. This is 

 true in less degree of most of the plants which form new shoots. In others— 

 Impatiens Holstii, Lycopersicum esculentum, Pelargonium peltatum, and 

 Tropaeolum majus—ih^ stems decay and the roots soon die. 



Some obser\^ations were made on periodicity of exudation and of exu- 

 dation pressure. These facts will be pubHshed in a separate note later 

 Sophia EcKKi?«nv i\fnrth.^^^.^f^^ %jr 



THE CONDITION OF CERTAIN WINTER BUDS 



. ^^ng 1905-1906 an effort was made to ascertain the seasonal stages 



m the microspore development of certain woody plants, with the foUowing 

 results: 



Populus deltoides 

 Fraxiaus americana. 

 Celtis ocddentalis. , . 

 Carpirras caroliniana 



Cornus florlda 



Cercis canadensis. . . , 



Dividii^ nuclei 



Mature spores 



Oct. 23~Feb. 15 

 October 24 

 October 24 

 August 20 

 October 31 



April 12 

 April 12 



AugTOSt 2 2 



April 17 



October 23 



April 15 

 April IS 

 Aiigust 24 

 April 20 



WiixiAM MooBX. and Mutv E. Behney, Ur sinus College, Pa 



