They utilize their specific leaf anatomy where chloroplasts exist not only in the mesophyll cells in the outer part of their leaves but in the bundle sheath cells as well.

Traced upward, it splits to enclose the subclavius, and its two layers are attached to the clavicle, one in front of and the other behind the muscle the latter layer fuses with the deep cervical fascia and with the sheath of the axillary vessels.