The "Tefilat Geshem" ("Prayer for Rain") recited on Shemini 'Atzeret contains six verses. Each verse refers to a different person (except the last, which refers to a nation) and makes various allusions to that person's interactions with water found in the Torah and Midrash, with the prominent repetition of the word "mayim" ("water") throughout and ending each verse.
The subjects of the six verses are:
- The 12 Tribes of Israel
If there's anyone in the Torah+Midrash who's associated with water, Miriam is, as the well on which the Israelites depended for their water in the desert was called "the Water of Miriam" in the Midrash. One of her other claims to fame was "Song of Miriam," the version of the Song of the Sea that she led the women to sing on the banks of the Red Sea. She's also known for the vigil she stood over her baby brother Moshe, when he was hidden in the Nile.
Why isn't there a verse of Tefilat Geshem devoted to Miriam?