Procambial Initiation for the Vascular System in the Rhizome ofOphiopogon(Asparagales)

Abstract

Figures from independent studies of 1941 suggested a similarity in the initiation of the vascular system of the arborescent palms and the unrelated and herbaceous lily turf, Ophiopogon. In order to compare more rigorously the vascular pattern of Ophiopogon with the intensively studied vascular system of the palms, cross sections of the rhizome of Ophiopogon were serially analyzed. All procambial strands were mapped in the 1.5‐mm‐long tip of a rhizome of Ophiopogon containing the insertions of 18 leaves. Charting procambia effected a description of the origins of the three major traces and the two intermediate traces associated with each leaf. All traces arise by merger of originally isolated procambia. A primary thickening meristem (PTM) with a horizontal roof and sloping sides furnishes the more distal components of the traces. The most proximal segment of a major trace differentiates in isolation in the residual meristem near the first horizontal procambia generated by the roof of the PTM. The procambia...