This section is from the "Histology of Medicinal Plants" book, by William Mansfield.
Reticulate vessels are of common occurrence in medicinal plants. In fact, they occur more frequently than any other type of vessel. The basic structure of reticulate vessels (Plate 43, Fig. 1) occurring in different plants is similar, but they vary in a recognizable way in different plants (Plate 43, Fig. 2). The walls of reticulate vessels are thickened to a greater extent than are the walls of spirally thickened vessels.
Plate 43. Reticulate Vessels.
1. Hydrastis rhizome (Hydrastis canadensis, L.). 2. Musk root (Ferula sumbul, [Kauffm.] Hook., f.).