Detail, Bidens pilosa stem - development associated with the vascular cambium.
|This cross-section of a Bidens stem,
shows a detail of the vascular tissues in the stem. The
cambium is active and is producing secondary vascular tissues. The
sieve tubes (ST) and companion cells. These are primary (1P) and
secondary (2P) beneath a thin layer of perivascular primary
phloem fibres (PV). The cortex is separated from the stele, by a starch sheath
The cambial zone contains a few differentiating secondary xylem e(2P) elements.
The image was taken using a microscope with polararized light.