FIGURE 4 Comparison of Cynanchum pingtaoi and C.
longhushanense : a–d
C. pingtaoi e–h C. longhushanense a, e flowers, front
view; b, f flowers, elevation view; c, g flowers, showing whether the
corona exceeds the corolla tube; d, h corolla separation, showing the
color of corolla lobe, corona lobe. All photos by Si-Jin Zeng.