1910.] 



ON THE DISTRIBUTION OF PLANTS. 



473 



Series of heights: 1.288, 1.293, i-300, 1.398, 1.413, i430, 1.473, 1-545, i-56o, 

 1.572. Arithmetic mean = 1.427. 



Length of spikes, $: .084, .087, .090, .091, .095, .113, .120, .126, .130, .145. 

 Arithmetic mean ^ .108. 



Breadth of spikes, ?: .021, .022, .023, .024, .025. Arithmetic mean = .023. 



Third Series. Typha angustifolia from Stockton L.\ke Shore (Position 

 III.) AT Head of Lake. Sp. gr. 1.005. 



Series of heights: 1.668, 1.678, 1.789, 1.803, i-8i5, 1.862, 1.882, 1.920, 2.026, 

 2.108. Arithmetic mean = 1.885. 



Length of spikes, $: .138, .141, .146, .154, .161, .162, .164, .166, .169, .182. 

 Arithmetic mean = .158. 



Breadth of spikes, $: .018, .020, .021, .022, .023, .024, .025, .026. Arith- 

 metic mean = .022. 



If we take the arithmetic means of the plant heights, lengths of 

 pistillate spike portions and breadths of pistillate spike portions of 

 the thirty plants taken from three separate localities along the shores 

 of Stockton Lake, we will appreciate the influence of the saline con- 

 ditions of the soil upon the relative size of the plants of these 

 three sets. 



Mean Dimensions of 30 Plants. 



This table clearly shows that the cat-tails in fresh water are much 

 taller than those growing under more saline conditions, and this 

 applies not only to the heights of the plants, but to the other dimen- 

 sions as well. 



PROC. AMER. PHIL. SOC, L. 201 FF, PRINTED AUG. 25, I9II. 



