plate; 43 
1. —General view of the small displaced vascular strands (concentric medullary 
bundles) shown at X in Plate 20. The coarse-celled outer tissue is pith. X75. 
2. —Structure in cross section of the larger of the two strands in figure i, xylem 
(spirals, tracheae, etc.) on the periphery, cambium ring midway, phloem in the 
center. At X are two sieve plates. X160. 
3. —Sieve plates of figure 2 further enlarged. Block 1288. Slide 4. X650. The 
perforations of these plates show quite well in the photograph, but are mostly lost in 
the overetched halftone. 
