PLATE VI. 



Fig. 9. — Longitudinal section through a young root of a Stigmaria. Medullary 

 cavity, a. Vascular cylinder, b, b. Vessels of the cylinder deflected to form a 

 rootlet bundle, /, passing out through a primary medullary ray, b' . Secondary 

 medullary rays, b"' . Cortex parenchyma, d. Cortex meristem, d' . Base of rootlet, 

 g. Rootlet cushion, h. X 10. Cabinet, No. 776. (Pages 14, 18, 19, 20, 22, 31, 

 34, 35.) 



Fig. 45. —Longitudinal section of the proximal end of another rootlet. Paren- 

 chymatous zone of the root-bark, d. Prosenchymatous zone of the root-bark, d'. 

 Rootlet bundle, /, enclosed within its rootlet bundle-sheath, /", and passing out- 

 wards through the rootlet cushion, h, h'. Apex of the rootlet cushion, li . Outer 

 cortical zone of the rootlet, g. X 18. (Pages 19, 26, 27.) 



