Adonis
Hypnotic in its beauty, but deadly if consumed. As you may have guessed, this plant is named after the hero of Greek mythology.
Azaleas
Most harmful if ingested by a dog, azaleas have a soft texture and petals that seem to flow with the wind. Azalea festivals are held in cities all over North America.
Belladonna
Also called "deadly nightshade," one of the most toxic plants in the western hemisphere, belladonna is often used as a recreational drug. The hallucinations produced by belladonna are typically unpleasant, however, and there are occasional unpleasant overdoses. It is also used for alternative and mainstream medicinal purposes.
Bloodflower
Its bright, cheerful colors are quite inviting and appropriate as ornamental plants. Although not healthy for human consumption, bloodflower is a food source for butterflies.
Crown Vetch
Toxic to horses, but beneficial for cultivating the earth, crown vetch has been named the state beautification plant of Pennsylvania.
False Indigo
Elegantly shaped, false indigo is not as bad as its name implies. It has a plethora of medicinal usages, but if consumed in excess, false indigo could induce vomiting or diarrhea.
Henbane
Also called "stinking nightshade," henbane can be fatal to animals in small doses. The "hen" part may not necessarily have to do with chickens...
Larkspur
Western varieties of larkspur are poisonous to cattle, but its delicate petals would have you believe its a faerie in disguise.
Lily of the Valley
Also known as "Our Lady's tears," lily of the valley looks more like a handle of little bells--serene and inviting. If untended, however, they can spread like wild fire.
Nightshade
More generally, nightshade is alsoknown as the potato family; some of these, like eggplant, are edible and others are indeed deadly.