MISSOURI BOTANICAL GARDEN BULLETIN 151 
this lady while walking in her father’s garden at Hammarly. 
She mentions its being visible only in the dusk of evening 
and ceasing when the darkness came on. Subjoined to her 
account are some observations by M. Wilckes, a celebrated 
electrician, who considered the phenomenon as being of an 
electrical nature.” 
_ The various collections of flowering plants in the Garden 
include a number of species of which the flowers—and in 
Tare cases the leaves—have been reported to display the 
rather phenomenal capacity of self-illumination. This 
ability is not a constant characteristic of the plants in which 
it has been observed, but appears intermittently. It is 
apparently of an electrical nature, since the illumination is 
reported to be very pronounced when the atmosphere is dry 
and the temperature high, and most striking immediately 
preceding electrical storms when the atmosphere is warm 
and sultry. 
The supposition that so-called phosphorescence in the 
flowering plants is of a physical nature, i. e., electrical, 
rather than the result of metabolic activity or an evidence 
of chemical changes taking place in the tissue, has been sub- 
stantiated by evoking this phenomenon experimentally. Pots 
containing plants were insulated from conducting material 
by piecing them on glass plates or on inverted glass tumblers, 
and the plants were then charged by means of a small elec- 
trostatic instrument. The gradual accumulation of the 
charge finally resulted in a difference of potential t 
enough to warrant a discharge from the flowers and buds 
identical with that observed in nature. In the light of these 
experiments and in view of the fact that in nature this phe- 
nomenon is observed when meteorological conditions are 
most favorable for electrical disturbances, we have reason to 
believe that self-illumination in the flowering plants can be 
accounted for on purely physical grounds. Some of the 
plants in which it has been observed are nasturtium (Tro- 
pacolum majus), firelily (Liliwm bulbiferwm), sunflower 
(Helianthus annuus), velvet-flower (Tagetes patula), poppy 
(Papaver orientale), and others, notably some occurring in 
tropical forests. It seems probable that the luminous mosses 
which have made certain caves in central Europe famous, 
likewise produce their light electrically. 
Some of the lower plants display phosphorescence which 
cannot be accounted for on physical grounds, about twenty- 
five species of bacteria, arid about as many species of fila- 
mentous fungi and “toadstools” having exhibited this 
capacity. In these plants light is not emitted at irregular 
intervals but as a continuous glow. tures of filamentous 
