Pistia stratiotes (Water lettuce)

4/6/2011 · Howard Peters Rawlings Conservatory & Botanic Gardens, Druid Hill Park, Baltimore, Maryland · ≈ 1½ × 1′ (52 × 34 cm)

4/6/2011 · Howard Peters Rawlings Conservatory & Botanic Gardens, Druid Hill Park, Baltimore, Maryland · ≈ 2 × 1′ (62 × 41 cm)

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	Araceae	Arum family, with plants whose flower is enclosed in a spathe
Genus	Pistia	From the Greek pistos, “water,” alluding to the floating or aquatic habitat of this genus, whose common name is water-lettuce
Species	stratiotes	From the Greek for “soldier,” applied to this aquatic herb because of its sword-shaped leaves