[Vor. 11 
412 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
П. MATERIALS 
The inflorescence of M. virginica is а favorable subject for work 
on the problem of fertility. Since all the flowers are arranged on 
a single axis, it is easy to consider the influence of position on the 
inflorescence upon the chances of development of the fruit and 
upon the characteristies of the matured fruit. Тһе flowers which 
fail to produce fruits leave a conspicuous scar, so that the number 
of flowers produced may be accurately determined. The ripened 
seeds have a fine black color and are easily counted. Unfor- 
tunately it is impossible to determine the number of ovules 
formed. Тһе trimerous nature of the fruit makes possible the 
consideration of certain problems concerning the interrelationship 
of numbers of seeds per locule. 
Collections of material were taken from 2 different localities. 
The first was the more open woods at Meramec Highlands, near 
St. Louis. Тһе second was the edge of the limestone cliffs along 
the Mississippi River, south of Jefferson Barracks, Mo. 
In the absence of quantitative criteria no attempt will be made 
to distinguish in any precise way between the conditions for plant 
growth in these 2 habitats. Тһе general impression conveyed 
by an examination of the two habitats was that growth at Mera- 
mec Highlands was much more luxuriant than that on the crests 
of the cliffs south of Jefferson Barracks. 7 
The countings made comprise the following :— 
1. Number of flowers per inflorescence (f). 
2. Number of capsules matured per inflorescence (c). 
3. The actual position of the capsule on the inflorescence (р). 
This is the position of the flower measured from the proximal end 
of the inflorescence. Thus the position of the first flower is 1, 
while that of the terminal flower is measured by the number of 
flowers produced on the inflorescences. 
4. Relative position of the capsule (r). This measures the 
position of the individual capsule in the series produced by 8n 
inflorescence. Thus the relative position of the lowermost capsule 
will be 1, whatever the position of the flower which produced it, 
while that of the most distal capsule will be the same 8$ - 
number of capsules produced by the inflorescence in question. 
