Triglochin palustre
 
Marsh Arrow-Grass

Flower, Stage 5

Hudson Bay, SK
29-July-2017

There are three outer tepals and three inner tepals.  Each tepal subtends an anther.  The outer tepals open up and expose their anther (and then largely fall off) before the inner tepals do.

The ovary is composed of three fertile carpels and three sterile carpels.  The ovary will develop into a schizocarp that will subsequently separate into three mericarps.