Opuntia microdasys ‘Alba’ (White polka dot cactus)

4/6/2011 · Howard Peters Rawlings Conservatory & Botanic Gardens, Druid Hill Park, Baltimore, Maryland · ≈ 17 × 12″ (44 × 29 cm)

4/6/2011 · Howard Peters Rawlings Conservatory & Botanic Gardens, Druid Hill Park, Baltimore, Maryland · ≈ 7 × 4½″ (17 × 11 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	Magnoliopsida	Dicotyledons—plants with two initial seed leaves
Subclass	Caryophyllidae	Cacti, many other succulents, carnivorous plants, and leadworts
Order	Caryophyllales	Includes cacti, carnations, amaranths, ice plants, and many carnivorous plants
Family	Cactaceae	Succulent (water-storing) plants, often spiny
Genus	Opuntia	Prickly pears
Species	microdasys	From the Greek mikros, “small,” and dasys, “hairy, shaggy”