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Dieffenbachia seguine (Jacq.) Schott 1832
pronounced: def-en-BARK-ee-uh suh-GEEN
(Araceae – the arum family)
synonym: Dieffenbachia maculata (Lodd.) Sweet 1839
pronounced: def-en-BARK-ee-uh mack-you-LAH-tuh
common name: Dumb Cane
Dieffenbachia is named for Dr. Ernst Dieffenbach, 1811–1855, German physician, naturalist and geologist, who was the first trained scientist to live and work in New Zealand. The origin of seguine is unknown; in the synonym, maculata is from the Latin maculatus, spotted.
Dieffenbachia is a genus of tropical plants in the arum family, noted for its patterned leaves. Members of this genus are popular as house plants because of their tolerance to shade. The cells of these plants contain needle-shaped calcium oxalate crystals, known as raphides. If a leaf is chewed, these crystals cause a burning sensation in the mouth and throat; swelling can occur along with a temporary inability to speak, hence the common name of the genus. Chewing and swallowing generally result in only mild symptoms, but can result in death if the swelling of the tongue and the throat blocks the airway. Young children and cats who chew at the leaves are particularly at risk. Slaves were sometimes punished by having Dieffenbachia put in their mouths.
The leaves of dumb cane are variegated with white, cream and yellow, and are very decorative. They can grow outdoors only in tropical climates, and are more usually found as house plants. Outside the tropics they need to be kept indoors for most of the year. The plant needs some light, but will usually be fine in a window with filtered sunlight. There is a relatively aggressive root system, so repotting may be a frequent task. When the plant sets new leaves, they look at first as if they have been rolled up. As with most plants kept indoors, the setting of new leaves is a sign that they are pretty healthy. Yellowing leaves are a sign of poor condition, and usually mean that the plant is in heed of nutrients; but a little yellowing and the occasional leaf drop should not give rise to too much concern.
Dieffenbachia do not often flower when in captivity, but, when they do, the flower is a very interesting one. The inflorescence is green in colour, and consists of a spadix and a spathe. The spadix consists of an upright central axis cover with several minute flowers without petals. There are separate male (staminate) and female (pistillate) flowers clustered about the same spadix. The male flowers are grouped on the upper half of the spadix, and the female flowers on the basal half. The spathe covers the spadix until the day of opening, when it unfurls and exposes the male portion of the spadix. The male flowers do not produce pollen until 2–3 days after the spathe begins to unfurl. This means that the female flowers (which are only receptive of pollen on the first day of opening) cannot be pollinated by pollen from the same flower. This prevents inbreeding. When cross-pollinating by hand, the male portion of the spadix is usually cut off and placed on a dish to facilitate the collection of pollen on a brush. The stigmas of the female flowers have a pale golden yellow colour. The pollinating brush is usually drawn across the surface of the stigmas, to make it sticky, before the pollen is collected. When the seeds form, they have a fleshy outer covering that is cleaned off before planting. They generally germinate within three weeks. I am told that seedlings do not show their adult variegation pattern until approximately 810 leaves have been produced. I have not personally counted them, but someone obviously has!
Photographs taken in Picnic Bay 2009, 2010
Page last updated 14th November 2016