Euphorbia amplexicaulis (Leafy spurge)

Plants: Small shrub, to 5′ (1.5 m) tall. Red stems are swollen at leaf nodes, and contain a milky sap when broken.

Leaves: Opposite, simple, roundish to heart-shaped, ⅛–⅜″ long ⨉ ⅛–⅜″ wide (3–11 ⨉ 4–11 mm). The cordate leaves clasp the stems.

Flowers: Cyathia, cup shaped structures unique to members of the euphorbia family, appear at stem tips. Each cyathium has four black glands with white to greenish appendages that look a bit like petals. There are 8-14 staminate flowers per cyathium, each with one stamen. There is also a single pistillate (female) flower. Both flowers lack a calyx or corolla.

Fruits: Broadly ovoid capsule, 1/16″ long ⨉ 1/16″ across (1.8 ⨉ 2.3 mm), with a single seed.

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	Rosidae	Roses, legumes, proteas, dogwoods, hydrangeas, mistletoes, euphorbias, grapes, many more
Order	Malpighiales	A broad group encompassing 16,000 species
Family	Euphorbiaceae	Euphorbia or spurge family
Genus	Euphorbia	An extremely diverse-looking genus of mostly tropical and subtropical succulent plants. For Euphorbus, corpulent Greek physician of Juba II, King of Mauretania. Literally, “euphorbia” means “well-fed”
Species	amplexicaulis	With the leaf base clasping the stem

About plant names...