IQIO.] 



ON THE DISTRIBUTION OF PLANTS. 



475 



Sixth Series. Typha angustifolia Collected at Head of Pleasure Bay. 



Sp. gr. i.ooo. 



Series of heights: 1.307, 1.430, 1.467, 1.543, 1.564, 1.615, 1-632, 1.642, 1.657, 

 1.688. Arithmetic mean ^1.554. 



Length of spikes, ?: .117, .134, .144. -MS- -U/- -U8. .1/3, -i^J, .193. 

 Arithmetic mean = .154. 



Breadth of spikes, $: .015, .016, .018, .019, .020. Arithmetic mean = .018. 



Constructing a table of means of the last three series, we dis- 

 cover that the heights of the cat-tails and the dimensions of the spike 

 increase with the decrease in the salinity of the water. 



Mean Dimensions of 30 Plants. 



Now, if we combine the two tables which demonstrate the mean 

 dimensions of the sixty measured plants collected from six widely 

 diverse positions, we will see at a glance that Typha aiujnstifoha 

 when found in soil with saline conditions, as indicated by the specific 

 gravity of the soil water, is reduced in size compared with other 

 plants growing under more, or less, fresh-water conditions. All of 

 the dimensions of the plants are influenced, but not in corresponding 

 proportions, and it is also noteworthy that the cat-tails in a more 

 saline soil are not only smaller in size, but show a more yellowish- 

 green appearance than the taller, darker green plants controlled by 

 fresh water. 



