Document Type : Original Article
Department of Botany and Microbiology, Faculty of Science, Cairo University, Giza, Egypt.
Systematic relationships in the Malvaceae s.s. and allied families were studied on the basis of numerical analysis. 103 macro- and micro morphological attributes including vegetative parts, pollen grains and seeds of 64 taxa belonging to 32 genera of Malvaceae s.s. and allied families (Sterculiaceae, Tiliaceae, Bombacaceae) were scored and the UPGMA clustering analysis was applied to investigate the phenetic relationships and to clarify the circumscription. Four main clusters are recognized viz. Sterculiaceae s.s. cluster, Tiliaceae- Exemplars of Strerculiaceae cluster, Malvaceae s.s. cluster and Bombacaceae s.s. – Exemplars of Sterculiaceae and Malvaceae cluster. The results delimited Sterculiaceae s.s. and Tiliaceae s.s. to containing the genera previously included in tribes Sterculieae and Tilieae respectively; also confirmed and verified the segregation of Byttnerioideae of Sterculiaceae s.l. and Grewioideae of Tiliaceae s.l. to be treated as distinct families Byttneriaceae and Spermanniaceae respectively. Our analysis recommended the treatment of subfamilies Dombeyoideae, Bombacoideae and Malvoideae of Malvaceae s.l. as distinct families: Dombeyaceae, Bombacaceae s.s. and Malvaceae s.s. and the final placement of Gossypium and Hibiscus in either Malvaceae or Bombacaceae is uncertain, as well as the circumscription of Pterospermum is obscure thus further study is necessary for these genera.