As evidence that Indian Ocean connections, and their role in crop dispersal, have been gaining increased attention, I would like to draw attention, somewhat belatedly, to two journal special issues of last year that may be of interest. At the very end of 2009 a special issue of the French periodical Etudes Ocean Indien (Vol. 42-43) devoted to plants and people was published. Articles are in either in English and French. Of particular interest personally, were papers by Lefevre on the indigenous classification of plants in part of Madagascar, the 'folk models' by which rice is understood in Madagascar explored by Hume, the use of wild plant foods and famine food on Zanzibar (by Martin Walsh), and a study of that interesting stimulant kat, chewed in Ethiopia and Yemen (by Carrier & Gezon); there is also a SEALINKS paper I wrote with Nicky Boivin on the crops, cattle, commensal small mammals and weeds [pdf] that have moved back and forth between India and East Africa in the past.
Slightly older, was a special issue of journal Ethnobotanical Research and Applications, devoted to bananas. While many paper focus on bananas in Asia, several touch on the movement of bananas between Asia and Africa, especially papers by Blench, and Hlidebrandt & Neumann; important paper of a more archaeobotanical/methodological slant are papers on phytoliths and banana seeds by Vrydaghs et al. and De Lange. The papers are all in the middle of the 2009 volume, starting from page 169. A full list of banana papers was posted previously on the archaeobotanist blog.