Butomus umbellatus (Flowering rush)

This Eurasian native is the only plant in its family. It was introduced as an ornamental to North America, and has become a serious invasive in the Great Lakes and in parts of the Pacific Northwest—it is illegal in several states, and the list is growing. (Searching for this species yields more warnings about invasiveness than it does descriptions of the plant.)

Plants: Although rushlike in appearance, this is not a rush. These freshwater aquatic plants are largely submerged.

Leaves: Linear, pointed, grasslike leaves are up to 8½′ ⨉ ⅛–⅜″ (2.7 m ⨉ 5–10 mm), extending from the roots. They are twisted, and lack teeth. Leaves have triangular cross sections.

Flowers: The inflorescence is comprised of a single terminal flower, surrounded by three cymes. Each umbrella-shaped inflorescence contains up to 50 flowers, with long thin pedicels resembling the umbrella’s spokes. Each flower is ¾–⅞″ (2–2.5 cm) in diameter, atop a long pedicel. It has three pink sepals, with darker pink veins, and three somewhat larger petals, as well as 6-9 stamens. They flower from July to August.

Habitats: Still or nearly still fresh water, at depths of up to 9½′ (3 m), in temperate climates.

Kingdom	Plantae	Plants, but not fungi, lichens, or algae (from Stearn's Botanical Latin)
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Magnoliophyta	Flowering plants, also known as angiosperms
Class	Liliopsida	Monocots (plants with a single seed leaf); includes the lily family
Subclass	Alismatidae	Aquatic and marshy plants
Order	Alismatales	Herbaceous flowering plants found in marshy habitats
Family	Butomaceae	For Butomus, the only member genus of this family
Genus	Butomus	From Greek bous, “cow,” or “ox,” and tome, “a cut” (the verb temnein meaning “to cut“)
Species	umbellatus	Umbrella-shaped

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