PORTULACARIA AFRA IN EAST AFRICA

Abstract

The Portulacaceae fascicle (Phillips, 2002) of the “Flora of Tropical East Africa” (FTEA) has one surprising entry. Portulacaria afra Jacq. is included for Kenya with the note that it “appears to be native”. In all other literature that I have seen, including the latest account of the succulent Portulacaceae (Rowley, 2002), this species is listed as native only to Mozambique, South Africa and Swaziland. Its appearance in Kenya is a remarkable major disjunction in distribution. The inclusion of Portulacaria afra in the FTEA is based on a single herbarium specimen at Kew, collected south of Kongolai, West Suk District (in FTEA area K2) by Mrs. E. Marjorie Tweedie. The specimen (Tweedie 3759) is dated February 1970. However, the FTEA also notes that this species is cultivated as an ornamental plant in Nairobi, and indeed I have it growing in my own garden. There is no specimen of this species in the East African Herbarium, Nairobi. In addition to being a very active plant collector, Mrs. Tweedie (1898–1982) was a botanical artist, producing both line drawings and paintings. Some of her artwork has been published (e.g. line drawings in Agnew & Agnew, 1994) and for her paintings she was awarded the Gold Grenfell Medal by the Royal Horticultural Society (U.K.) in 1933. In 1980 Mrs. Tweedie presented her paintings to the Kew Herbarium library. There are about 1500 paintings, mounted in seven albums with brief handwritten notes for each. With the albums of paintings is a typescript from Mrs. Tweedie (1979) with notes on some of the plants illustrated. On page 27 of album no. 1 there is a painting of Portulacaria afra, with the following caption: