The arum family
Araceae is the family behind two flowers that are not flowers and one plant that is not a lily. Calla lilies and anthuriums both belong to it, and in both cases the colored part everybody calls the flower is a modified leaf. It is also the family that supplies half the houseplants in the country.
around 140 genera
roughly 3,700 species
Mostly tropical, with a scatter of temperate members
Everything in this guide that belongs to Araceae
The structure here is unlike anything else. The real flowers are tiny and packed onto a fleshy spike called the spadix, which is the finger in the middle of an anthurium and the yellow rod inside a calla. Wrapped around it is the spathe, a single modified leaf that has taken on the color and the job of a petal.
So the glossy red heart of an anthurium is a leaf, and the white trumpet of a calla is a leaf rolled into a cone. Neither has petals at all. Once you know that, the family becomes obvious everywhere: peace lily, flamingo flower, arum lily and the enormous titan arum are all the same two-part arrangement at different scales.
Because a spathe is structural leaf tissue rather than delicate petal tissue, it lasts extraordinarily well. Anthurium runs three to six weeks in water, which is longer than almost anything else a florist sells, and the calla is not far behind.
Calla lily is a misnomer twice over. It is not a lily, it belongs to no part of the lily family, and it is not even the genus Calla. The flowers sold under that name are Zantedeschia, from southern Africa, and the true Calla is a small bog plant from the northern hemisphere.
The name has been in trade use for so long that arguing with it is pointless, but the distinction matters for one practical reason. True lilies are lethally toxic to cats, and customers who know that will sometimes refuse anything with lily in the name. A calla is not a lily and does not carry that specific danger, which is worth being able to say clearly.
That is not the same as saying it is safe. This family has a toxicity of its own, and it applies to every member.
Araceae tissue carries calcium oxalate in the form of raphides, microscopic needle-shaped crystals bundled in the cells. When the tissue is chewed or crushed the bundles fire, driving thousands of tiny needles into whatever is in contact with them.
The effect on a mouth is immediate burning and swelling, which is why dumb cane earned its name and why every member of this family should be kept away from children and pets. On hands it is milder, an itch or a rash with prolonged handling, but people who process calla stems in quantity do notice it.
The practical habits are simple. Rinse the cut ends, avoid rubbing your eyes while working, and wash up afterward. Calla stems also bleed a good deal of watery sap and are prone to curling and splitting at the base, so recut cleanly and use shallow water rather than deep.
Peace lily, monstera, philodendron, pothos, dieffenbachia and ZZ plant are all in this family. If a house has plants in it, some of them are almost certainly Araceae, which is a useful thing to know when a customer asks what will survive a dim hallway.
Taro is here too, and it feeds a very large number of people across the Pacific, Africa and Asia. It has to be cooked thoroughly, and the reason is precisely those calcium oxalate crystals: heat and long preparation break them down.
The family also contains the most theatrical flowers on earth. The titan arum produces the largest unbranched flower structure of any plant and smells of rotting meat to attract carrion flies, and several members generate real heat, warming the spadix well above the surrounding air to carry that scent further. Nothing in a florist's cooler does that, but it is the same spathe and spadix doing it.