58 Proceedings of Societies. (January, 
limestone at Independence, Iowa. One of the shells found in this shale 
belonged to a genus that began its existence, so far as known, in the 
Marcellus shales, and this fact together with the position of the shale, 
justified its reference to the Marcellus epoch. The discovery of this 
shale with its carbonized plants explains the numerous reports that have 
gained circulation at various times, concerning the discovery of coal in 
regions occupied by Devonian rocks. 
Professor Bessey read a note on The Colors of Iowa Wild Flowers, 
presenting tables prepared with a view of determining what influence the 
total amount of light and heat exerts on the predominant colors of the 
native Flora. 
ACADEMY or NATURAL Sciences, Philadelphia. — August 8th. Mr. 
Thomas Meehan referred to observations he had made this season on 
the nocturnal and diurnal expansion of flowers, and said that, contrary 
to the popular impression, it was not probable that light or its absence 
alone determined the opening of the blossoms. There were some plants, 
as for instance Wnothera biennis (the evening primrose), Anagallis 
arvensis (the pimpernel), and others, which remained open or other- 
- wise, longer when the weather was humid or clear, and were looked on 
in consequence as a kind of floral barometers ; but from other facts it 
was clear that it was not the weather merely, but some other incident 
_ accompanying the weather, which governed the case. 
Though @nothera biennis and other CEnotheras opened at evening, 
and if the atmosphere was moist would continue open the greater part of 
the next day, many species opened only in the daytime, and this they 
did regularly, quite regardless of meteorological conditions. @nothera 
serrata of Colorado was one of these. It was regular in opening about 
noon, and the blossoms were all closed long before sundown. 
In other allied families we saw similar divergences. In the cactus 
family Opuntia and Mammillaria opened only about midday, while most 
of the Cereus opened at night. The night blooming cactus was a famil- 
iar example. But the chief interest was in the fact that many had their 
special hours of day or night for the expansion. The Portulaca oleracea 
(common purslane) opened about eight a. m., and by nine o'clock ha 
performed all its functions, while a closely allied plant, the Talinum 
teretifolium, from the serpentine rocks of Chester County, opened at one . 
P. M. and was closed by three o'clock. The conditions of the weather 
did not seem to influence them. 
There was the same attention to daily periods in the growth of the 
parts of plants as well as in the expansion of the petals. In composite 
plants the floral growth was wholly in the morning, and was usually 
over by nine or ten o’clock a. m. The elongation and expansion of the 
corolla was usually completed in an hour after sunrise, but the stamens 
grew for an hour more, and the pistils continued for still another. There © 
was little if any growth in the floral parts after nine o'clock in a very 
