ABSTRACT
Morphological studies on Nigerian Terminalia Linn. with emphasis on anatomical details of the leaf and stem of the present-day T. ivorensis A. Chev. were undertaken with a view to updating species delimitations and elucidating characters which are common on the Terminalia ivorensis A. Chev. “complex”. Exomorphological studies of fresh and dried herbaria samples, habits, distribution of all these woody, indigenous and exotic trees of importance in National Resource Programme and also anatomical vessel evidence from T. ivorensis, indicated that the species are mesophytes, perennials and dicotyledons. The characters in common are aggregation of leaves at stem tips, racemose inflorescence with male and hermaphroditic flowers on same stalk. Other present life characters such as Pagoda or ill-formed pagoda, sympodial branches which are common go to confirm their belonging to the same genus. Studies on Natural habitat, vegetative (bole length, bark, leaf size, shape, base, tip) and reproductive features carried out comparatively showed variations of taxonomic value/usage. Earlier texts had reported numbers 4, 6, 9 species in the acnus. However this study recognises 14 distinct species. Newly to be enlisted into Nigerian Terminalia species are T. albida, Sc. Elliot T. arjuna Roxb. (Wight and Arn). T. bellerica Roxb. T.mantaly, H.Perrier. and T. pennyana Anozie sp. nov. Monographic works described all the species, attempted classificatory studies using more extensive information than were used before. Economic, ethnobotanical /medicinal values were highlighted under circumscriptions of the species for incorporation into future “Flora of Nigeria”. Identification of species was by comparison with descriptions in available African Floras and matching with available Types specimen. Certain herbarium specimens mistakenly defined in UNN and FHI collections were re-identified. A key using more details in characters than Keay’s (1989). Key was constructed to separate all the species including those delimited newly compiled. Fruit character which featured prominently in the present Key agreed in sequence with Keay’s(1989). A combined distribution map showed that T. superba was allopatric, and often associated with species of T. ivorensis in lowland rain forest belt. Terminalia. arjuna is restricted to mangrove coastal type vegetation. Other species are T. laxiflora T. avicennoides, T. schimperiana and T. pennyana associates or overlapping in distribution in derived Savanna. The long-boled trees of T. ivorensis found growing luxuriantly along major streets (Boulevard Babangida Way) and in Secretariats of Federal Capital City Abuja, Nigeria were ornamentals probably cultivated. T. catappa with large medicinal leaves, variety of edible fruits in size, shape, colours and T. mantaly are now home shade trees commonly found, practically in every town in Nigeria, animal or water distributed. Terminalia catappa and T. mantaly are cultivated exotic species now common especially as shade and decorative trees across Nigeria. Other Terminalia trees located in the country and of various sizes have numerous uses mentioned in circumscription section and these include fodder for cattle, local dye production, ink, tannin for leather industry, fuel firewood and charcoal production and honey culture. Texture of stem bark, stem slash colour, leaf basal end, leaf tips of T. ivorensis showed so much variation that according to Stace (1980) such species could be referred to as T. ivorensis “group” or “complex”. Evidence of fused multiseriate rays with decrease in multiseriate number and increasing abundance of biseriate and gradual increase in uniseriate rays as in VAO3 agreed with what Esau (1977) explained as a plant under-going evolution. Wood of long bole timber, T. ivorensis has long vessel members (plesiomorphous) unlike the more rugged bole trees of T. pennyana with very short vessel elements which are regarded apomorphous. Tendency to short boled maturing (fruiting) T ivorensis trees have been observed in this same environment. Four winged fruit common in Combretum genus was occassionally found in T. ivorensis suggesting some relationship and that T. ivorensis group or complex is undergoing evolutionary change. Phytochemical screening revealed that T. pennyana in addition to presence of tannin and essential oil common in genus contained alkaloids, flavonoids, saponin, resin, acidic compound, carbohydrates, reducing sugars, steroids and terpenoids all of which have potentials as raw materials for industry. Information and data accrued in this project will form the basis for future investigation. The presence of pollen of exotic T. catappa in honey of bee hives with physical observation of biodiversity destruction of the very trees VAO1, VA07 studied, in fact stressed by Stuessy (2011) has reawakened the awareness for conservation of these multipurpose indigenous and exotic tree crops facing extermination. In current Agricultural Taungya system of practice in Ghana T. ivorensis is being intercropped with Carica papaya and this was observed in Delta State.
