Which plant's all parts are toxic, with seeds containing a cardiac glycoside?

Which plant's all parts are toxic, with seeds containing a cardiac glycoside? Lily of the valley is the answer. Its scientific name is Convallaria majalis, a woodland plant known for fragrant, bell-shaped white flowers and red berries.

The plant contains numerous cardiac glycosides, also called cardenolides. These compounds can disrupt the normal electrical activity of the heart, potentially causing nausea, vomiting, abdominal pain, confusion, irregular heartbeat, and—in serious cases—death. The roots, leaves, flowers, berries, and seeds are all poisonous if eaten.

A common mix-up is foxglove, another plant famous for cardiac glycosides. Foxglove is also highly toxic, but its tall flower spikes and spotted, tubular blossoms are very different from lily of the valley's low woodland sprays. Oleander is another cardiac-glycoside plant, yet it is a woody shrub rather than a delicate spring perennial.

Lily of the valley has a long history in gardens and perfume-making because of its powerful fragrance. Its beauty and sweet scent make the plant especially dangerous around children and pets, who may be attracted to its berries.