Fig. 2.

Pollination and pollen reception in Trithuria submersa. (A) Cross-section of a dehiscent anther showing numerous endothecial bands (arrow), aerenychma ground tissue and the two stomia just beginning to open (one indicated by an arrowhead). Scale bar = 50 µm. (B) Mature reproductive units of T. submersa with fully elongated filaments supporting dehiscing anthers (developmental stage 4). The stigmatic hairs are visible above and between the reflexed bracts (arrowhead). Scale bar = 5 mm. (C) Staminate flower of wind-pollinated Brasenia schreberi with dehiscing anthers supported by long, slender filaments. Compare to B. Scale bar = 5 mm. (D) Receptive stigmatic hair (from a developmental stage 3 reproductive unit) with germinating pollen grains (two in plane of focus). Scale bar = 25 µm. (E) Carpel in which cross-pollination was prohibited, with self-pollen tubes successfully reaching the carpel mouth. Scale bar = 150 µm. Abbreviations: A, anther; F, filament; L, aerenchyma; M, carpel mouth; H, stigmatic hair; P, peduncle; PG, pollen grain; PT, pollen tube.