Primitive A ngio sperms . 163 
just before the insertion of the lateral traces on it. When this insertion 
takes place, which is not until the three traces are close to the stele of the 
hypocotyl, the symmetry of the midrib-trace is not affected. 
Figs. i-6. Delphinium requienii : i, seedling, showing nearly sessile cotyledons; 2, double 
bundle from petiole of cotyledon; 3, cotyledon (enlarged), showing venation; 4-6, diagrams of 
transition from stem to root. Here, as in later diagrams, protoxylem is black, metaxylem dotted, 
and phloem merely outlined. 
Figs. 7, 8. Nigella damascena : 7, upper part of seedling; 8, transverse section of petiole of 
cotyledon. 
Fig. 9. Althea rosea : upper part of seedling. 
