Crassula aquatica

Lore & Background

Crassula aquatica is a small plant forming thin mats or small patches on mud and sand, and growing more erect when exposed to open air for longer periods. The flesh of the plant is greenish-yellow to bright red or purplish. The tiny fleshy pointed leaves are only a few millimeters long. A flower grows on a short stalk from the intersection of each oppositely-arranged pair of leaves; the flower is only about two millimeters long and wide. The fruit is a minute follicle containing several seeds.

This plant is widespread across North America and Eurasia. It is an annual plant of salt marshes, vernal pools, wetlands, and other fresh to brackish water bodies. It is at least partially aquatic, living in areas which are submersed much of the time. It also lives along muddy banks and in tidally-active areas of estuaries.

It is listed as a vulnerable species in Newfoundland and Labrador. Cavan Allen rediscovered Crassula aquatica in Maryland in 2012 after it had been last seen in that state in 1950.

Reader's Guide

Crassula aquatica is notable for its ability to thrive in both submerged and emergent conditions, forming thin mats on mud and sand while growing more erect when exposed to air. Its small size—with leaves only a few millimeters long and flowers about two millimeters across—makes it a subtle but resilient component of its habitats. The plant's flesh ranges from greenish-yellow to bright red or purplish, adding color to the wetlands and estuaries it occupies. Its distribution across North America and Eurasia indicates a broad ecological tolerance, though it is listed as vulnerable in Newfoundland and Labrador. The rediscovery of Crassula aquatica in Maryland in 2012 by Cavan Allen, after it had not been seen there since 1950, highlights its rarity and the importance of continued survey efforts. As an annual species, it completes its life cycle within a single growing season, producing minute follicles containing several seeds. Its presence in tidally-active areas and brackish waters underscores its adaptation to fluctuating salinity and water levels.

Did You Know?

• Crassula aquatica is known by the common names water pygmyweed, common pygmyweed, and just pigmyweed.
• Its flowers are only about two millimeters long and wide.
• Cavan Allen rediscovered this plant in Maryland in 2012 after it had been last seen there in 1950.