The genus Dieffenbachia was named after Herr Joseph Dieffenbach, head gardener and later administrator, at the Royal Palace Gardens Schönbrunn, Vienna during the 1830s. It is said that Dieffenbach brought Dieffenbachia seguine to Austria from Brazil around 1830. If true, Dieffenbachia was one of the plants returned to Europe by the Austro-Brazilian expeditions (1817-35) that began the expansion of our understanding of the plants of Brazil and South America.
There are 25 to 50 Dieffenbachia species originating from tropical America. Dieffenbachia seguine is grown for its distinctively marked, paddle-shaped leaves which can be up to 40 cm long. The leaves have a broad, creamy white midrib, with varying degrees of marking to other veins, and some spotting set on a glossy-green backdrop. Numerous named cultivars have been selected for their leaf markings which may make identification of Dieffenbachia seguine difficult. The stems are strong and thick and can reach 2-3 m in height in the wild, although in cultivation they are usually much shorter since if they do get too tall they tend to fall over. The tiny flowers are clustered on a spadix about 15 cm long, with the uppermost male flowers separated from the female flowers by a row of sterile flowers. The flowers are surrounded by a large, pale-spotted, light green spathe. The fleshy fruits are orange-red in colour.
In Oxford Botanic Garden, Dieffenbachia seguine grows in the Palm House, where the light levels mimic the low light of the forest floor, the species' natural habitat. Dieffenbachias prefer high humidity and a minimum temperature of 12° C, although preferred temperatures are nearer 18° C. Propagation is by tip cuttings, stem cuttings, division and air layering during the growing season. Dieffenbachias tend to be relatively pest and disease free, although, as in any tropical glasshouse situation, mealy bugs and red spider mites can be a problem.
The sap of dieffenbachias contains calcium oxalate, and is poisonous. Consequently, great care must be taken when handling dieffenbachia plants, especially over getting sap into the mouth and eyes. One response the sap provokes is swelling of the throat, resulting in speechlessness; hence the common name 'dumb cane'. In Amazonia, indigenous people use the sap to poison their arrows and it used to be used as a punishment for slaves, causing a very painful, swollen mouth and excessive saliva. In spite of the dieffenbachias toxicity, they are widely sold as pot plants.
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