Sacagawea Springs

Sacagawea Springs is a natural spring near Great Falls, Montana. The water flowing out of the spring forms a large pool where a species green algae, Chara vulgaris, can be found in abundance.

Although species of Chara can be found in many different habitats, they often form large mats in alkaline waters. In the upper photo, essentially all of the submerged aquatic vegetation is comprised of Chara vulgaris. Chara can grow to be a meter or more in length and form mats hundreds of meters long! Some species of Chara become encrusted in calcium carbonate in alkaline waters which gives them a coarse texture and one of their common names: stoneworts. Another common name, muskgrasses, comes from their distinctive musky odor.

All members of the Characeae (including Chara) are composed of a series of multicellular nodes with whorls of branches connected by giant single-celled internodes. They have specialized male and female reproductive structures. Because they become encrusted in calcium carbonate, Characeae are well represented in the fossil record. In particular, the female reproductive structures (called gyrogonites once fossilized) are abundant in some fossil sediments.

Chara vulgaris

Sacagawea Springs gets its name from the native American guide who accompanied the Lewis and Clark Expedition to the West. She used the mineral springs as a medicinal bath. Read more about the springs at Discovering Lewis & Clark