Acanthocereus (Engelm. ex A. Berger) Britton & Rose

Pollen.

trizonocolpate, radially symmetrical, isopolar with circular contour in polar view. Shape: varies from subprolate to oblate-spheroidal (P/E=0.97-1.29). Apertures: 3, colpate, large; polar area of medium size (PAI=0.31-0.40). Measurements: pollen grains of large size (49.02)56.81(68.53) × (49.89)63.62(79.4) μm in equatorial view; exine thickness (2.41)3.29(4.19) μm . Ornamentation: smooth surface with tectum perforate, ornated with spinules of (1.05)1.43(1.76) μm length × (1.08)1.37(1.83) μm diameter in base; perforations (0.17)0.25(0.33) μm in diameter (Figure 3A).

Species examined.

Acanthocereus tetragonus (L.) Hummelinck (Colombia, Valle del Cauca. C. Ruiz et al. 576 CUVC); Acanthocereus chiapensis Bravo ( México, Chiapas. C. Gómez-Hinostrosa et al. 2325 MEXU).