The translation of “a Querschnitt durch die Wurzelspitze von Equisetum hiemale dicht unterhalb der Scheitelzelle nach Naegeli und Leitgeb,” according to Google, is: A cross-section through the apex of Equisetum hiemale just below the apical cell after Naegeli and Leitgeb.
Equisetum hymale is a horsetail, a primitive plant. An apical cell is the one at the tip that keeps growing – the cell that makes the other cells of the stem. Naegeli and Leitgeb were two guys who did a lot of looking through telescopes at tiny bits of plants, figuring out how all the itty bitty parts snapped together.
This illustration is from a German study of plant cell biology: Studien über die zellteilung im pflanzenreiche. Ein beitrag zur entwicklungsmechanik vegetabilischer gewebe by Karl Friedrich Georg Giesenhagen.