1912] HARRIS—STAPHYLEA 205 
to the statistician, different series of material to yield somewhat 
discordant results. 
For a first study it seemed undesirable, considering the irregu- ~ 
larity of the pod, to take measurements in fine units, and readings 
were made of the length of the fruit to the nearest o.5 cm. The 
number of ovules formed and the number of seeds developing can 
be fairly easily counted. 
II. Material 
Shrubs of Staphylea growing in the “North American Tract” of 
the Missouri Botanical Garden furnished the material for this 
investigation. These are in part the individuals upon which a 
study of selective elimination?, was based in the spring of 1908, and 
the numbers of the plants are comparable. 
In 1906 the fruiting of Staphylea seemed to be quite normal, and 
a series of about roo fruits each were obtained from 20 shrubs. In 
1907 there was a severe frost which inhibited entirely the fruiting 
of some of the trees; altogether only 1218 fruits were obtained, as 
compared with 2059 in 1906. In 1906 the fruits were taken from 
shrubs 11-20, but in 1907 it was necessary to take shrubs 11-41 to 
get 16 individual series of material of suitable size. Only three- 
loculed fruits were used. 
In the reduction of the data the biometric methods, now familiar 
in a general way to most working biologists, were used.’ For the 
benefit of biologists who are inclined to be wary of mathematical 
symbols, I may explain that no difficulties of that kind will be met 
if a few simple ideas are kept in mind. For convenience and terse- 
ness of expression, the characters investigated are designated by 
letters: o=number of ovules per locule*; s=number of seeds per 
locule‘; f=number of ovules failing to develop to mature seeds per 
locule‘; p=position of fruit on the inflorescence; n=number of 
fruits per inflorescence; 7,>7o is to be read “‘the correlation (r 
being the symbol for correlation) between the length of the pod 
s, J. Artur, On the selective elimination occurring during the develop- 
ment of the fruit of Staphylea. Biometrika 7: 452-504. 1910. 
3 Unless especially noted, SHEPPARD’S correction was not used for the second 
moment. 
4 Or occasionally total number per fruit, when this is indicated by the context. 
