118 BOTANICAL GAZETTE [ FEBRUARY 
nuclei, and starch grains existed in cork zones four to five layen 
removed outside the phellogen. 
22. The structure and developmant of internal phloem in Gi 
semium sempervirens: Miss CAROLINE THompson, University o 
Pennsylvania.—The author showed that the internal phloem 
originated as four longitudinal tracts in the primary meristem, 
and steadily increased until by the eighth or tenth year it had 
entirely pressed together and destroyed the pith. During th 
first year nourishment of the pith ceased, owing to the differ 
tiation of two layers of cells, which were referred to as the 
‘phloem sheath.” 
A remarkable distribution of the internal phloem was sho 
to exist in the petiole, at the base of which a bicollateral bundle 
arrangement existed, but this quickly changed to the ordinat) 
collateral relation by the passage of the upper (internal) phloca 
through the xylem of the petiole. Each bundle in passing 0% 
into the petiole subdivided into three parts, two of whit 
remained in the stem and soon came together again, while the 
third passed out and behaved as above described. 
From the second year onward, the internal phloem patches 
of the stem show areas of crushed and obliterated tissue, whet 
the previously formed phloem had been pushed inwards by f 
younger elements. In older stems eight large phloem pat 
formed by division of the original four, entirely filled up the 
area. 
