BIOMETRIC DATA IN CRINUM LONGIFOLIUM. 85 
For constants (in the half gram units as indicated in the 
tables) I find: 
Mean Weight of Seed :— 
OOD as ieee ose 5.565 + .121 
PROG T iar se 4.369 + .045 
ries ees 1.176 + .129 
Standard Deviation :— 
PSUR ye eer oe 3.282 + .086 
1B0G Ft Bee eh ee 2.971 + .032 
LE. Sev ee oll + .092 
Coefficient of Variation :— 
LOUD GAs Gedy 58.972 + 2.007 
L0G 35 a? 67.697 + 1.000 
Uiliepey ce eee 8.725 + 2.242 
Apparently, the two series differ significantly in mean 
weight of seed, those for 1905 being about half a gram 
heavier than those of 1906. This is not at all a surpris- 
ing result, for the weight of a Crinum seed must depend, 
in large measure, upon availability of plastic material and 
water. The variability, as shown by the coefficient of varia- 
tion, is very great. Perhaps the variability differs for the 
two years, but because of the skewness of distribution, the 
probable errors calculated by the ordinary formule may 
not give decisive tests. 
The relative variabilities for seed weight, like those for 
number of seeds per pod, are high, but data for compari- 
son from other species are rare. Johannsen® gives coeffi- 
cients of variation of from 10.5 to 17.5 for “pure lines” of 
beans, and I have found generally comparable values for 
large series of Phaseolus vulgaris. I know of no other data. 
4. The Relationship between the Size of the Inflorescence 
and its Capacity for maturing Fruits. 
This problem has already been considered for immature 
6 Rep. Third Int. Conf. Genetics 109. 1907. 
