Monadenium (2003)

PhotoBy Roy D. Kasten (August 2003)

Monadenium belongs in the Euphorbiaceae family. This genus has 50 known species, 46 of which are confined to tropical East Africa. Its eastern distribution line is the Indian Ocean. This genus does not exist in Madagascar. Throughout its area of distribution, endemic species, varieties and forms of Monadenium are numerous, with their habitat often restricted to singular hilltops.

Monadeniums have a milky sap that may be harmful to the touch. The inflorescence has a complicated structure which consists of one reduced female flower and several male flowers. There are protective bracts and nectarines. The fruit is a capsule which explodes on reaching maturity.

The word monadenium is derived from Greek and means “single gland,” based on the initial species of the genus to be described, Monadenium coccineum. This distinguishing characteristic for which the name was applied emanates from the flower structure. Flowers consist of a cuplike bracteate head, truncated at the top and open at one side or below the middle with a “single gland” of varying width on its top margin.

Many monadeniums have a comparatively large rootstock and a minimum of organs necessary for reproduction so that minimum energy is wasted developing stems above ground. Although the genus is remarkably free from disease and insect problems, it is susceptible to rot when exposed to moisture in the winter. The genus across the board is a winter-dormant plant, and as such must be kept absolutely dry during this period.

Culture of the genus varies between species, but the general rules of succulents apply to this genus. Well-drained soil is always required, water only when in leaf and feed with low-nitrogen fertilizer during the growing period. Exposure to sunlight depends on the species and variety.

The plants should be shaded if signs of sunburn occur. Typically the anthocyanins (red pigments) present themselves when given too much sun and the opposite with well-shaded plants. The chlorophylls become prominent when more shade is given. (Source: Tom DeMerritt, “Expinas Y Flores,” October 2000.)

All the monadeniums I have were obtained through co-members of the club. Bring yours in and perhaps we can do some plant or offset swapping.