PRATT: CYCLOLOMA ATRIPLICIFOLIUM. 99 



As seen in cross section (figs. 5, q, and 6, q), the three inner 

 phloem zones are interrupted by numerous radial anastomosing 

 strips of xylem (figs. 5, n, and 6, u). The other phloem zones are 

 traversed by a much lesser number of these (fig. 6). The radial 

 strips of xylem are usually made up of wood fibers, as shown in 

 fig. 10, u, although some contain trachese, as sho%vn in fig. 56, u. 

 The peculiar location of these radial anastomosing strips of xylem 

 is due to the varied activity and anastomosis of the arcs of sec- 

 ondary meristem by which the radial anastomosing strips of 

 xylem were formed. The anastomosis of the arcs of secondary 

 meristem is described above. The phloem zones in region V and 

 below are joined up in cross section by radial anastomosing strips 

 of tissue ha\ing cells which resemble the secondaiy medullary ray 

 cells (figs. 6, g', and 58, g'). 



As seen in cross section, in the anomalous zones there are radial 

 rows of cells having a radial dimension from two to four times as 

 gi-eat as their tangential dimension (fig. 58, g'"). These radial 

 rows of cells are narrow, being only one to four cells broad tangen- 

 tially. None of these radial rows of cells in the sections examined 

 extend entu'ely from the outer to the inner zone of anomalous 

 growth, but generally traverse only a few zones. In the phloem 

 zones these cells are pericycle cells (fig. 58, h'") and secondary 

 medullary ray cells (fig. 58, i'"). In the xylem zones these cells 

 resemble wood parenchyma in size and proportion, and have thick, 

 slightly lignified walls (fig. 57, j'"). 



As far as the writer has been able to ascertain, no use made of 

 the anomalous structure by the plant has been mentioned in the 

 literature available. 



I am of the opinion that the anomalous xylem is an ample 

 strengthening tissue, and serves principally for water storage, not 

 so much for conduction. Probably the xylem of the primary 

 vascular bundles conducts sufficiently for the transpiration of the 

 leaves. The leaf-trace bundles traverse the two innermost an- 

 omalous xylem-phloem zones in region IV (fig. 29, t"). Below 

 region IV the leaf-trace bundles are broken apart by further 

 anomalous growth (fig. 29, u"), and the leaves do not remain on 

 this region of stem. Evidently from region IV on down the stem 

 all the anomalous xylem zones are available for water storage. 



The presence of many phloem strands in the anomalous struc- 

 ture is quite striking, for it seems there is enough phloem in the 

 primary vascular bundles to conduct the photosynthetic prod- 

 ucts of the leaves. But there is much photosynthetic tissue in 



