Six months later, in late September, it is demonstrating the characteristic black color of Phyllostachys nigra . The leaf blade magnified approx 10x, and is illuminated from below to show the leaf veining in greater detail. The parallel veins are connected with cross veins running at right angles. This characteristic pattern of veining is called tessellation. This photo, taken with a macro lens through a scope with 40x magnification with illumination from both top and bottom, shows the connecting veins running at right angles.
Tessellation is considered an indication of cold hardiness in bamboo.