426 , Worsdell. — Origin and Meaning of Medullary 
Fig. i. Tragopogon orientatis. Transverse sections of the extreme base of the central cylinder 
of the stem, numbered from below upwards. The medullary strands are lettered alphabetically in 
the order of their appearance. (Diagrammatic.) Fig. 2. Tragopogon. Longitudinal section of 
the lower part of the central cylinder of the stem, showing the typical origin and course of 
the medullary strands in the genus. (Diagrammatic.) It = leaf-trace ; mb — medullary bundle ; 
mps = medullary phloem-strand ; vs = main vascular system (referred to in other diagrams as the 
‘ vascular .ring’). Fig. 3. Tragopogon orientalis. Segment of vascular ring, showing internal- 
phloem strands ( mps). x 10.- Fig. 4. . Tolpis barbata. Vascular ring, showing transitions 
between some of its constituents and the medullary bundles (mb). Rudimentary medullary 
strands (bundles and phloem-strands) shown at ms. x 4. 
