THE ANATOMY OF THE STEM OF THE CALYCANTHACEHi. 
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4. The pith is heterogeneous. 
The periphery of the pith consists of a small-celled tissue containing chloroplasts. 
The central cells are larger, and after the first year lose their contents. 
5. Foldings in cell walls. 
The radial walls of the first-formed cork cells are elongated, and, almost immedi- 
ately after formation, show marked foldings (fif. 15), especially in the region outside 
the peripheral bundles. In Chimonanthus, the phloem of the central stele is crushed 
beneath the peripheral bundles, and the inner tangential walls show foldings. 
Foldings were also observed in the pith of C. fertilis. 
6. The occurrence of oleiferous cells. 
Glandular cells occur in the cortical parenchyma of all species of Calycanthus. 
In Chimonanthus they are found in the bast, the pericyclic parenchyma, and in the 
pith, as well as in the cortical parenchyma. In old stems the walls are slightly 
lignified. 
7. The occurrence of pits on the walls of the cortical cells. 
Pits invariably occur on the walls of the cortical cells both in the parenchyma 
and collenchyma. 
8. The presence of unicellular silicified hairs. 
These hairs occur on the epidermis. They are long and bent near the base in 
both Calycanthus and Chimonanthus. 
9. The occurrence of scalariform tracheides. 
Scalariform tracheides similar to those occurring in Pteridophyta are found in 
C. fertilis, C. jloridus, C. occidentalism and Chimonanthus fragrans var. grandifiora. 
10. The occurrence of spiral or reticulate tracheides with bordered pits in the 
secondary xylem. 
These are found in every species examined, except C. fertilis. In C. occidentalis 
they are very abundant, to the exclusion of all other elements except the libriform 
fibres. The bordered pits may be uniseriate or multiseriate. The lumina of these 
tracheides are often blocked by tyloses. 
1 1 . Multiseriate bordered pits. 
Tracheides with multiseriate bordered pits are frequent in C. fertilis, C. foridus, 
and Ch. fragrans var. grandifiora. Here tyloses are also frequent. 
12. Double spirals in the primary tissues. 
Double spiral thickening is seen on the walls of the vessels of C. jloridus and 
Ch. fragrans ; they also occur on the tracheides of the latter. 
13. The occurrence of lateral sieve-plates. 
Lateral sieve-plates were found in C. fertilis, C. occidentalis, and Ch. fragrans 
var. grandifiora. 
