Dieffenbachia seguine 'Amoena'
This is a genus of about 30 species of evergreen perennials from the tropical forests in North and South America and the West Indies. Most are cultivars derived from D. seguine (I'm calling the one pictured here 'Amoena', but that's a guess) which is also referred to as D. maculata.
They are grown for their beautiful foliage.
The plant can grow to three feet in a pot, some species even taller.
This plant is also known as "Mother-in-Law's Tongue" or "Mother-in-Law's Plant" for reason's which I will explain. There are so many plants with this common name, one almost feels bad for Mother's-in-Law's. They're getting a bad rap. (OK, maybe not.)
All parts may cause severe discomfort if ingested, and contact with the sap may irritate the skin and eyes. Named "Mother-in-Law" or Dumb Cane for the same reason - it will cause your tongue or insides of mouth to swell preventing further discussion. When picking dead leaves off I have gotten a rash which lasts for a few hours, so I always wash my hands thoroughly immediately after handling the plant. Also, unlike most plants that do not look that appetizing (to little kids), this one looks delicious.
You don't need to worry about merely brushing up against the leaves. It is not poisonous to the touch like poison ivy (see shower story, below).
Dieffenbachia is mentioned a number of times in Amy Stewart's book, "Wicked Plants."
Soil, Water, and Light
Soil should be potting soil with coarse sand or perlite. It should be placed in good light, not bright light, not direct sunlight. It needs plenty of moisture so I set mine in a tray of gravel which is always filled with water. Water sparingly (seem inconsistent, but you don't want the roots or stem to rot or encourage mold) so let the top of the soil dry between waterings and in winter reduce the amount you water even more (say, once every two weeks).
I summer all houseplants outdoors once the temperatures get above 45 degrees at night. This plant, outdoors, should be placed in light shade, never getting direct sunlight. In the summer, I also keep a tray of gravel filled with water under it.
I've had the best luck indoors placing this plant in a very bright (outdoor window) large shower where the water does not hit the plant (and fill the pot) but it always has moisture. Before I started doing this, the plant would always go dormant in the winter, the leaves turning brown and falling off (almost completely). It always came back in the spring, though, no matter how bad it looked. Some leaves should be expected to turn brown and fall off, under even the best conditions.
If you don't keep it in the shower, then mist it every once in a while.
From April to June you can do tip cuttings. Cut four to five inches, making the cut just beneath a node. Remove the lower leaves and dip in a rooting preparation and stick the cutting in a moist mixture of potting soil and sand or perlite. Place a transparent plastic bad over it to keep the moisture in and place in bright light.
I've read that you can air layer larger leaves.
I also understand that cuttings will root rapidly in water.
Mold (mentioned above), red spider mites, mealy bugs.