Limiting ray lignification (variant portion). (A) Transverse section of Pyrostegia venusta. Limiting rays lignify only next to the xylem (white arrow), with its phloem portion non-lignified (black arrow). (B) Transverse section of Tynanthus elegans. Limiting rays are lignified next to the xylem and phloem (black arrows), with a row of cells remaining non-lignified in the middle portion (white arrow). (C) Transverse section of Dolichandra unguiculata. Limiting rays do not lignify, even in the xylem (arrows). (D) Ancestral character state reconstruction of limiting ray lignification. VC, variant cambium; X, xylem Scale bars = 200 µm.