DaffodilKropsoq, Wikimedia Commons

Some favorite flowers and prized plants can be four-legged friends' worst enemies. The American Society for the Prevention of Cruelty to Animals lists hundreds of pet-poisoning plants, including these 10.

Daffodil Danger

Squirrels tend to leave daffodil bulbs alone. That's good news for gardeners, but bad news for cats and dogs. The bulbs are the most toxic part of the plant and can poison dogs and cats.

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TulipsTulip fields with the Rijnsburg windmill. (Claude Monet, Wikimedia Commons)

Tulip bulbs are toxic too, and not just to pets. Humans should think twice before tasting a tulip. In fact many plant's roots and bulbs hide toxic defenses. Even the seemingly benign potato can develop dangerous levels of the poison solanine, if the spuds grow too close to the surface and turn green.

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PeriwinkleSelena N. B. H, Wikimedia Commons

Periwinkle may have a sissy name, but this ground cover can kill a cat or dog if they ingest it. The poison punch of periwinkle comes from vinca alkaloids. Those same chemicals once served as anti-cancer drugs until they were replaced by synthetics.

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RhododendronsFg2, Wikimedia Commons

Showy rhododendrons can be the end of the road for pets. Eating a few leaves can cause serious problems, even death. The plant contains a nasty nerve poison, grayanotoxin. That poison can contaminate honey if bees feast on rhododendrons. In Nepal, this tainted honey fetches a high price because of its supposed medicinal properties, reported National Geographic.

AloeFrank Vincentz, Wikimedia Commons

The slimy sap of an aloe plant can sooth burned skin, and the chemicals, known as saponins, make aloe a naturally foamy shampoo. But those same chemicals are deadly to fish -- and cause vomiting, diarrhea, and tremors in cats and dogs.

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The Pond and Erman Biology Center at the University of Chicago.Bob Krist/Corbis

The signature vegetation of higher education, English ivy, also contains saponins -- particularly one known as hederagenin, which some people take as a stimulant. The effects on pets, however, are anything but stimulating. Ivy can make cats and dogs very sick and the leaves pack more toxic punch than the berries.

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ChamomilePikiwikisrael, Wikimedia Commons

Chamomile tea may sooth human nerves, but the plant can cause allergic reactions in cats and dogs as well as skin irritation, vomiting and diarrhea.

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ApplesU.S. Department of Agriculture, Wikimedia Commons

An apple a day may be good for people, but the leaves, stems and seeds of apple trees release cyanide when chewed. Humans too can be exposed to cyanide if they chew up apple seeds. However, it would take approximately 100 grams of crushed apple seeds to poison an average size adult human, according to the Naked Scientists.

ColeusRoger Price, Wikimedia Commons

Oils in the many-colored foliage of coleus plants can cause vomiting and bloody diarrhea in dogs and cats.

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DaisiesJessica Merz, Wikimedia Commons

Daisies and other chrysanthemum species contain natural pesticides that can poison pets. However, those natural pest poisons -- including sesquiterpene, lactones, and pyrethrins -- make daisies an excellent guard plant to deter pests form attacking other, less-defended flowers and crops. Helpful bees, though, are undeterred.