Aphanorhegma Patens in Iowa

In the autumn of 1939, our Botany class went on a field trip to the Iowa River Valley in Tama County near Montour. We went especially for the purpose of gathering mosses and liverworts. Upon our return, we began an examination of our specimens, and I discovered a species of the genus Aphanorhegma in my collection. It had been growing on the mud of the river bank by Kronk\u27s bluff. There are only two known species of Aphanorhegma; one of which is patens, and the other serratum. In Iowa, the only reported species to date is the latter, serratum. The most distinguishing characteristic of serraturn is that the exothecial cells of the capsule are collenchymatous. By the word collenchymatous we mean that definite thickenings are present on the cell walls, usually at the corners. As a matter of routine, I mounted a portion of the capsule to make observations of the cells. I found that they were thin-walled and not in the slightest manner collenchymatous. Further observations proved that my species at hand was patens