Most of today’s entry was written by Claire with respect to the first photograph. I’ve added the second photograph and a little bit of commentary at the end. Claire writes:
Ton Rulkens (tonrulkens@Flickr) provided us with this beautiful photograph via the BPotD Flickr Pool of the flower of Manihot esculenta ‘Maria’ taken in Chimoio, Mozambique. Thank you Ton for helping us continue with the plant diversity and food series!
Manihot esculenta, or, commonly, cassava, manioc or yuca is a member of the Euphorbiaceae or spurge family. It is originally known from Brazil and Paraguay, but has spread to nearly all tropical regions around the world. There are no known wild types of this plant–it has been classified as a cultigen (like rice), i.e., it is only known from cultivation. The largest producers of Manihot esculenta are Nigeria, Brazil, and Thailand. As it needs at least eight months of sun, and does not tolerate frost well, the plant can only be cultivated in the tropics (and does particularly well in savanna climates).
The large, starchy root is often used as the edible part of the plant (although the leaves can also be eaten if prepared properly) and is the staple source of food for much of the equatorial world. Approaches to processing of the root by different cultures ranges from boiling or baking, to drying or fermenting. Because of its high and pure starch content, cassava has many uses. It is typically known in the temperate world as the ingredient of boba or pearls in tea slushes and tapioca (tapioca pudding anyone?). In countries where it is the staple carbohydrate source, people make alcohol, paste, flour, pudding and syrups out of the root. In addition to a human food, the cultigen is also beginning to be harvested as a biofuel for ethanol production as well as for animal feed. The Animal Feed Resources Information System states that the leaves and stems are used to harvest protein meal for animal feed. Almost six tons of crude protein can be obtained per hectare!
Due to Manihot esculenta‘s high content of cyanogenic glucosides, cassava is toxic when eaten raw or processed improperly. Cyanides released from the cyanogenic glucosides can cause a disease called konzo, which is permanent and paralytic. Of the two varieties, sweet and bitter, the bitter plants have the highest concentrations and the disease is common in women in children in rural parts of Africa where the bitter variety is very common. The root must be processed and prepared properly in order to remove the majority of these toxins.
Daniel adds: the second photograph features some cassava chips I picked up on the weekend (I knew Claire was writing about cassava this week). These have since been shared with most of the UBC Botanical Garden staff, and it seemed to me that everyone thought they were tasty, if not delicious.