Studies on the taxonomy, distribution and economic importance of the Genus Clutia L.(Clutieae, Euphorbiaceae) in Tanzania.

The genus Clutia L. (Euphorbiaceae) in Tanzania has been studied with special reference to the infrageneric taxonomic status, distribution pattern and medicinal potential of the genus. Nine species have bean treated taxonomically, 11 on the distributional pattern and 7 taxa on aspects of medicinal uses. Taxonomic studies based on taxometrics and pollen grain morphology has revealed that the three varieties of C. abyssinica Jaub and Spach, critical group, that is C. abyssinica var, abyssinica Jaub and Spach., C. abyssinica var, pedicellaris (Pax) Pax and C. abyssinica var, usambarica Pax and Hoffmann warrant consideration to be raised to specific ranks thus: C. abyssinica Jaub and Spach., C. pedicellaris (Pax) Hutch and C. usambarica Pax ex Hoffmann stat. nov. respectively. C. mollis Pax, much considered by Alpha-taxonomists to be a synonym of C. abyssinica var. usambarica qualify to be raised to a specific rank on taxometric grounds. The view is also accorded by palynological data. Five species namely C. robusta Pax and C. whytei Hutch., C. paxii Knauf, C. stuhlmannii Pax and C. angustifolia Knauf appear to form morphological stable groups. C. polyadenia Pax and C. rotundifolia Pax were studied to their distribution aspects only due to unavailability of Material. The geographical distribution of the genus Clutia in Tanzania has been mapped out. The general pattern has revealed that C. mollis var. usambarica C. polyadenia, C. rotundifolia, C. whytei, C. paxii, C. robusta, C. angustifolia and C.stuhlmannii are endemics and, only var. abyssinica and var. pedicellaries are widely distributed. Temperature and rainfall regimes including edaphic factors appear to dictate the observed distribution pattern. The genus appears to be in flower through-out the year and is apparently independent of seasonality. Ethnobotanical information on the genus hints on some medicinal potential for the taxa especially the C. abyssinica group. Diseases reputed to be cured by the various taxa include cancer, systemic disorders, chest problems, headaches, female disorders, purging and snake bites. Some taxa are also used as stimulants.