Also found in: Medical.
bicollateral bundle[‚bī·kə′lad·ə·rəl ′bənd·əl]
(in plants), a conducting bundle in which two shafts of phloem adjoin the wood from the outer and inner sides. The bicollateral bundle consists of one complete collateral bundle and a closely adjoining incomplete bundle. A bicollateral bundle is characteristic of the stems of members of the Cucurbitaceae and Solanaceae families.