An open collateral bundle is one in which :
xylem and phloem are seprated by cambium;
xylem and phloem lie side by side
cambium occurs on the out side of bundle
cambium does not occur in the bundle
A.
xylem and phloem are seprated by cambium;
Collateral bundle, that is, phloem on outside and xylem on inner side. It is open when a strip of cambium is present between xylem and phloem. e.g., dicot and Gymnosperms stem.