Indigenous Angiosperm biodiversity of Olabisi ... - Academic Journals

African Journal of Biotechnology Vol. 4 (5), pp. 554-562, June 2005 

Available online at http://www.academicjournals.org/AJB 

ISSN 1684–5315 © 2005 Academic Journals 

Full Length Research Paper 

Indigenous Angiosperm biodiversity of Olabisi 

Onabanjo University permanent site 

Mike O. Soladoye, Mubo A. Sonibare*, Adeniyi O. Nadi, and Dolapo A. Alabi 

Department of Plant Sciences and Applied Zoology, Olabisi Onabanjo University, P.M.B. 2002, 

Ago-Iwoye, Ogun State, Nigeria. 

Accepted January 27, 2005 

The conservation of the genetic variability of the indigenous angiosperm community is a sine qua non. 

A survey of indigenous angiosperm biodiversity of the Olabisi Onabanjo University permanent site was 

undertaken. Plants collected were dried, poisoned and mounted on herbarium sheets, proper 

identification and confirmation in recognized herbaria were carried out. A total number of one hundred 

and thirty-eight (138) plant species belonging to fifty-five (55) families were collected. Of these, one 

hundred and twenty-seven are dicotyledons and eleven are monocotyledons. Leguminosae is the 

largest family with thirteen plants followed by Rubiaceae with eleven and Euphorbiaceae with nine 

plants. Trees were found to have significantly contributed to the ecosystem with a total number of fiftyfour 

species, while forty-three of shrubs were recorded, climbers ten, herbs twenty-eight, grasses and 

sedges three. From this study it is obvious that the University permanent site is not only rich in plant 

biodiversity but also very rich in socio-economic values. Consequently it is highly advisable that a 

representative sample of this vegetation is protected for posterity so that all the indigenous plants of 

the study area may not be lost to the development projects embarked upon by the University. 

Key words: Conservation, indigenous angiosperm, biodiversity, Olabisi Onabanjo University. 

INTRODUCTION 

One of the most important nonrenewable aspects of any 

vegetation, be it small or large is the gene pool. The 

genotypes of the angiosperm community within the area 

mapped out for the University has been fashioned by 

millions of years of natural selection. It is obvious that 

most of these genotypes will be lost due to University 

developmental projects. This gene pool may never be 

recreated. We simply do not know how to recreate a 

species once it has become extinct (Kimmlins, 1987). It 

is only wise for now to at least have an inventory of this 

indigenous (angiosperm) biodiversity and to make 

appropriate recommendation for the preservation of 

representative sample which will be large enough to 

encompass the local variation of genotypes and which 

*Corresponding author. E-mail: sonibaredeola@yahoo.com, 

Tel: 08033659517. 

will ensure the survival of the angiosperm genetic 

diversity of this area. Although the question as to how 

large this representative sample will be in order to 

maintain this diversity of species has tremendous 

practical implications (Lovejoy and Oren, 1981). 

The Olabisi Onabanjo University campus site (Figure 

1) situated in Ago-Iwoye falls within the equatorial belt of 

Nigeria at longitude 3° 55 '' east of the Greenwich 

Meridian and latitude 6° 56 '' , north of the equator. Ago- 

Iwoye is about 7 km from Oru and about 5 km from Ijebu- 

Igbo, which are the two major towns in the Ijebu North 

Local Government area. The town is about 100 km 

Southeast of Abeokuta, the Ogun State capital (Master 

plan, 1985). The site lies to the South-western part of 

Ago-Iwoye approximately 35 km from the centre of the 

town and is bounded on the North by Ijebu-Igbo/ Oru/ 

Ago-Iwoye/ Ijesha-Ijebu/ Ilishan road and on the east by 

Ago-Iwoye/ Imodi-Imosan/ Ijebu-Ode road. The perimeter 

roads are connected to Lagos-Benin expressway and the

Figure1. Sample location Olabisi Onabanjo University, permanent campus. 

Table 1. Identified key species. 

S/N Botanical name Family Local name 

1 Abrus precatorius L. Leguminosae Oju ologbo, omisinmisin 

2 Ageratum conyzoiodes L. Compositae Imi-esu, imi-ewure 

3 Albizia ferruginea (Guill. & Perr.) Benth. Leguminosae Ayinre ogo 

4 Albizia lebbeck (L.) Benth. Leguminosae Igbagbo 

5 Alchornea cordifolia (Schum & Thonn. Muell. Arg. Euphorbiaceae Ipa, esinyin 

6 Alstonia boonei De Wild. Apocynaceae Awun 

7 Alstonia congensis Engl. Apocynaceae Awun 

8 Amaranthus spinosus L. Amaranthaceae Tete elegun, tete dagunro 

9 Anacardium occidentale L. Anacardiaceae Kaju 

10 Anchomanes difformis Engl. Araceae Igo, isu igo, okuku 

11 Aneilema umbrosum (Vahl) Kunth. Commelinaceae - 

12 Anthocleista djalonenis A. Chev. Loganiaceae Shapo, ishapo 

13 Anthocleista vogelii Planch. Loganiaceae Shapo 

14 Aspilia africana (Pers.) C.D. Adams Compositae Yun-yun, yunrinyun 

15 Asystasia gangetica (L.) T. Anders Acanthaceae Lobiri 

16 Azadirachta indica A. Juss. Meliaceae Eke-oyibo, dongo yaro 

17 Bambusa vulgaris L. Gramineae Oparun 

18 Baphia nitida Lodd. Leguminosae Irosun, owiwi, igiosun 

19 Bixa orellana L. Bixaceae Osun buke 

20 Boerhaavia diffusa L. Nyctaginaceae Etipase-eranla 

21 Bombax buonopozense P. Beauv. Bombacaceae Ponpola, eso 

22 Borreria verticillata G.F.N. Mey. Rubiaceae - 

23 Byrsocarpus coccineus Schum & Thonn. Connaraceae - 

24 Calliandra portoricensis (Jacq) Benth. Leguminosae - 

25 Calotropis procera (Ait.) Ait. F. Asclepiadaceae Bomubomu 

Soladoye et al. 555

556 Afr. J. Biotechnol. 

Table 1. contd. 

26 Canna bidentata Bertoloni Cannaceae Ido, idoro 

27 Capsicum frutescens L. Solanaceae Ata-jije, ata-eiye 

28 Carpolobia lutea G. Don. Polygalaceae Oshun 

29 Cassia fistula L. Leguminosae - 

30 Cassia obtusifolia L. Leguminosae - 

31 Chassalia kolly (Schum.)Hepper Rubiaceae Isepe agbe 

32 Chromolaena odorat (L.) King & Robinson Compositae Awolowo, akintola 

33 Cissampelos owariensis P.Beauv. Menispermaceae Jenjoko, jokoo-jee 

34 Cleome ciliata Schum. & Thonn. Capparidaceae Akuya-ajaa, ekuya 

35 Clerodendron umbellatum Poir Verbenaceae - 

36 Cnestis furruginea DC. Connaraceae Omu-aja, akara-aja 

37 Cnestis longiflora SChellenb. Connaraceae Ekayin 

38 Coix lacryma-jobi Linn. Gramineae Aje, aka-ila 

39 Cola acuminata (P.Beauv.) Schott & Endl. Sterculiaceae Obi-abata, obi-gidi 

40 Cola millenii K. Schum Sterculiaceae Obi-edun, obi aya 

41 Cola nitida (Vent.) Schott & Endl. Sterculiaceae Obi gbanja 

42 Combretum racemosum P. Beauv. Combretaceae Ogan-ibule, ogan-pupa 

43 Crotalaria retusa Linn. Leguminosae Koropo 

44 Culcasia scandens P.Beauv. Araceae Aginmona 

45 Cymbopogon citratus (DC) Stapf. Gramineae Oko oba, koriko oba 

46 Deinbollia pinnata Schum & Thonn. Sapindaceae Ogiri-egba 

47 Dichapetalum madagascariense Poir Dichapetalaceae Afere, afoforo, afee 

48 Dioclea reflexa Hook. F. Leguminosae Ise, agbaarin 

49 Dombeya buettneri K. Schum. Sterculiaceae Ewremo, ofo 

50 Duranta repens Linn. Verbenaceae - 

51 Elaeis guineensis Jacq. Palmae Idi-eyin, ope, igi ope 

52 Eleusine indica Gaertn. Gramineae Ese-kanna kanna 

53 Emilia coccinea (Sims) G. Don Compositae Odondon-okun, odundun 

54 Eugenia jambos Linn. Myrtaceae - 

55 Eugenia malaccensis Linn. Myrtaceae - 

56 Euphorbia heterophylla Linn. Euphorbiaceae Egele 

57 Euphorbia hirta Linn. Euphorbiaceae Emi-ile, egele 

58 Ficus benjamina Linn. Moraceae - 

59 Ficus exasprata Vahl. Moraceae Eepin 

60 Ficus mucuso Welw. ex. Ficalho Moraceae Oguro 

61 Ficus sur Forssk. Moraceae Opoto, opeya, abe-odan 

62 Funtumia africana (Benth.)Sapf. Apocynaceae Ako-ire, ire 

63 Gossypium barbadens Linn. Malvaceae Owu, ogodo 

64 Grewia carpinifolia Juss. Tiliaceae Itakun okere 

65 Harungana madagascariensis Lam. Ex. Poir. Hypericaceae Adenden 

66 Hedranthera bateri (Hook. F.) Pichon Apocynaceae Agbo-omode 

67 Hippocratea velutina Afzel. Celastraceae - 

68 Icacina tricantha Oliv. Icacinaceae Gbegbe 

69 Indigofera macrophylla Schum ( Thonn. Leguminosae Enise-ana 

70 Ipomoea mauritiana Jacq. Convolvulaceae Tanpopo, ododo-oko 

71 Ixora coccinea Linn. Rubiaceae - 

72 Jatropha curcas Linn. Euphorbiaceae Botuje, lapalapa 

73 Jatropha gossypifolia Linn. Euphorbiaceae Botuje-pupa 

74 Jussiae abyssinica (A. Rich.) Dandy & Bren. Onagraceae Ogbolo-eme-en 

75 Landolfia dulcis var. barteri (Sapf.) Pichon Apocynaceae Ibo 

76 Lantana camara Linn. Verbenaceae Ewon-adele, ewon agogo 

77 Lecaniodiscus cupanoides Planch. Sapindaceae Aaika, aika 

78 Leptoderris micrantha Dunn. Leguminosae Awo 

79 Luffa cylindrica (L.) Roem. Cucurbitaceae Kankan-ayaba 

80 Macrosphyra longistyla Hook. Rubiaceae Ikuuku-ekun 

81 Malacantha alnifornia (Bak.) Pierre. Sapotaceae -


82 Malvastrum coromandelianum (L.)Garcke. Malvaceae - 

83 Mangifera indica Linn. Anacardiaceae Mangoro 

84 Manihot glaziovii Muell. Arg. Euphorbiaceae Igi-isana 

85 Mariscus alternifolius Vahl. Cyperaceae Alubosa eranko 

86 Microdesmis puberula Hook. F. ex. Planch. Pandaceae Esunsun, aringi 

87 Milicia exelsa (Welw.) C.C. Berg Moraceae Iroko 

88 Mimosa pudica Linn. Leguminosae Patanmo aluro, patanmo 

89 Morinda morindoides (Bak.) Milne-Redh. Rubiaceae Oju-ologbo 

90 Morinda lucida Benth. Rubiaceae Oruwo 

91 Musanga cecropioides R. Br. Moraceae Aga, agbawo 

92 Mussaenda elegans Schum. & Thonn. Rubiaceae Ado, odo omode, ori ile 

93 Myrianthus arboreus P.Beauv. Moraceae Ibishere 

94 Napoleona imperialis P. Beauv. Lecythiaceae Abobidooyoo 

95 Nauclea latifolia Smith Rubiaceae Egbesi 

96 Newbouldia laevis Seem. Bignonaceae Akoko, ogise 

97 Olax subscorpioidea Oliv. Olacaceae Ifon, ifoon 

98 Oxyanthus formosus Hook. F. Rubiaceae - 

99 Passiflora foetida Linn. Passifloraceae - 

100 Paullinia pinnata Linn. Sapindaceae Kakasenla, ogbe-okuje 

101 Peltophorum pterocarpum (DC) Heyne Leguminosae - 

102 Phyllanthus amarus Schum. & Thonn. Euphorbiaceae Eyin-olobe, dobi-sowo 

103 Physalis angulata Linn. Solanaceae Koropo, papo 

104 Platycerum alcicorne (Willem) Oesv. Polypodiaceae Afomo 

105 Pleioceras barteri Baill. Apocynaceae Abeji, ireno-kekere 

106 Polyalthia longiflora Annonaceae - 

107 Psidium guajava Linn. Myrtaceae Guaba, gilofa 

108 Quisqualis indica Linn. Combretaceae Ogan funfun, ogan-igbo 

109 Rauvolfia vomitora Afzel. Apocynaceae Asofeyeje, adapopo 

110 Ricinodendron heudelottii (Baill.) Pierre. Euphorbiaceae Erinmadon, ogbodo 

111 Rothmannia longiflora Salisb. Rubiaceae Kakadika 

112 Rytigynia umbellulata Robyns. Rubiaceae Oju-eja 

113 Sabicea calycina Benth. Rubiaceae Jire, ogan apero 

114 Salacia pallescens Oliv. Celastraceae Elewekan 

115 Scoparia dulcis Linn. Scophulariaceae Naruntantan 

116 Securinega virosa (Roxb.) Baill. Euphorbiaceae Awewe, iranje 

117 Sida acuta Burm. F. Malvaceae Esoketu 

118 Smilax kraussiana Meisn. Smilacaceae Eha, ekanamagbo 

119 Solanum torvum Swatz Solanaceae Igba-yanrin-elegun-un 

120 Sphenocentrum jollyanum Pierre Menispermaceae Akerejupon, ajo 

121 Stachytarpheta cayennensis (DC. Rich.) Schau. Verbenaceae Agogo igun, akitipa 

122 Stachytarpheta indica (L.) Vahl Verbenaceae Ogan akuko, ogangan 

123 Stachytarpheta mutabilis Jacq. Vahl. Verbenaceae Iru alangba 

124 Synsepalum dulciferum (Schum & Thonn.) Daniell Sapotaceae Agbayun 

125 Talinum triangulare (Jacq.) Willd. Portulaceae Gure, gbure 

126 Terminalia randii Bak. F. Combretaceae - 

127 Thaumatococcusdaniellii (Benn.) Benth. Marantaceae Eeran, katemfe 

128 Trema orientalis (L.) Bl. Ulmaceae Afe, ofefe, ofoforo 

129 Triclisia subcordata Oliv. Menispermaceae Alugbirin, alugbonran 

130 Tridax procumbens Linn. Compositae Sabaruma, adegbile 

131 Triplochiton sclerexylon K. Schum. Sterculiaceae Obeche, aifo, arere 

132 Tristemna incompletum R.Br. Melastomaceae - 

133 Triumphetta cordifolia A. Rich. Tiliaceae Itogbin, esua 

134 Triumphetta rhomboidea Jacq. Tiliaceae Akeeri 

135 Urena lobata Linn. Malvaceae Ilasa-oyinbo, ilasa-omode 

136 Vernonia amygdalina Del. Compositae Ewuro, ewuro oko 

137 Voacanga Africana Stapf. Apocynaceae Sherenkpen, ako dodo 

138 Waltheria indica Linn. Sterculiaceae Epa esure, ewe epo 

Soladoye et al. 557


Ijebu-Ode/ Ibadan road. The tropical rain forest to which 

the vegetation of the campus belongs constitutes an 

evergreen plant community rich in trees, shrubs and 

herbs. The climate is characterized by high temperature 

and a bimodal rainfall pattern. The annual rainfall ranges 

from 1250 to 2190 mm beginning from mid-March to mid- 

November, with the peak in July and September. The 

mean annual minimum and maximum temperatures are 

about 20°C and 30°C respectively, while relative humidity 

is approximately 60% in the dry season and 90% in the 

rainy season. 

The present study aims at the conservation of the 

indigenous angiosperm genetic variability of the Olabisi 

Onabanjo University permanent site. 

MATERIALS AND METHODS 

The survey involved several visits to the site for collection of 

samples. Specimens were collected across the undisturbed and 

disturbed vegetation of the campus. Samples were dried, poisoned 

and mounted in accordance with conventional herbarium practice. 

Solvents used in poisoning include methylated spirit, Para 

dichlorobenzene (PCDB), 2% mercuric chloride, cyanide gas and 

naphthalene (Okoli et al., 1992). Identification of the specimens 

was done by experts by comparison with herbarium specimens in 

Elikaf herbarium of the Olabisi Onabanjo University (not listed in 

Holmgren and Keuken, 1998), the Forest Herbarium, Ibadan (FHI) 

and the University of Ibadan herbarium (UIH). Specimens collected 

were deposited at the Elikaf herbarium. 

RESULTS 

One hundred and thirty-eight (138) plant species (Table 

1) belonging to fifty-five families were identified as 

constituting the major part of the vegetation of the site. 

The Leguminosae has the largest number of species 

(thirteen) followed by Rubiaceae (eleven) and 

Euphorbiaceae having nine species (Table 2). The 

preponderance of the occurrence of species of the 

Euphorbiaceae and in particular Rubiaceae could be due 

to the climatic condition, soil type and the seed dispersal 

mechanism of the members of the family. Fifty-four tree 

species (Table 3, Figure 2) were collected on the whole 

showing the dominant role played by trees in the 

vegetation of the site. Most of the plants collected have 

simple leaves this is an indication of primitiveness as 

simple leaves are believed to have evolved earlier than 

the compound leaves (Radford et al., 1974). Also the 

solitary inflorescence was observed in many cases. More 

than 85% of the ecosystem is constituted by the 

dicotyledons (Figure 3). Plants like Chromolaena odorata 

(L.) King and Robinson and Aspilia africana (Pers.) C.D. 

Adams were found in almost all areas of the site. This 

supports the fact that weeds are notorious and inevitable 

in all vegetation types. Musanga cecropioides R. Br. 

provides shade and comfort in quite a number of portions 

in the site. 

Table 2. Species distribution according to families. 

Family Number of 

species 

Acanthaceae 1 

Amaranthaceae 1 

Anacardiaceae 2 

Annonaceae 1 

Apocynaceae 8 

Araceae 2 

Asclepidaceae 1 

Bignoniaceae 1 

Bixaceae 1 

Bombacaceae 1 

Cannaceae 1 

Capparidaceae 1 

Celastraceae 2 

Combretaceae 3 

Commelinaceae 1 

Compositae 6 

Connaraceae 3 

Convolvulaceae 1 

Cucurbitaceae 1 

Cyperceae 1 

Dichapetalaceae 1 

Euphorbiaceae 9 

Gramineae 4 

Hypercaceae 1 

Icacinaceae 1 

Lecythidaceae 1 

Leguminosae 13 

Longaniaceae 2 

Malvaceae 4 

Maranthaceae 1 

Ulmaceae 1 

Melastomaceae 1 

Meliaceae 1 

Menispermaceae 3 

Moraceae 7 

Myrtaceae 3 

Nyctaginaceae 1 

Olacaceae 1 

Onagraceae 1 

Palmaceae 1 

Pandaceae 1 

Passifloraceae 1 

Polygalaceae 1


Polypodicaeae 1 

Portulaceae 1 

Rubiaceae 11 

Sapindaceae 3 

Sapotaceae 2 

Scorphulariaceae 1 

Smilaceae 1 

Solanaceae 3 

Sterculiaceae 6 

Tiliaceae 3 

Verbenaceae 7 

Table 3. Habit of species. 

Botanical name Habit 

Abrus precatorius Twining herb 

Ageratum conyzoiodes Hispid herb 

Albizia ferruginea Tree 

Albizia lebbeck Tree 

Alchornea cordifolia Shrub/smalltree 

Alstonia boonei Tree 

Alstonia congensis Tree 

Amaranthus spinosus Herb 

Anacardium occidentale Tree 

Anchomanes difformis Herb 

Aneilma umbrosum Straggling herb 

Anthocleista djalonenis Tree 

Anthocleista vogelii Tree 

Aspilia africana Herb 

Asystasia gangetica Herb 

Azadirachta indica Shrub/smalltree 

Bambusa vulgaris Shrub 

Baphia nitida Shrub 

Bixa orellana Small tree 

Boerhaavia diffusa Herb 

Bombax buonopozense Tree 

Borreria verticillata Herb 

Byrsocarpus coccineus Climber / shrub 

Calliandra portoricensis Shrub 

Calotropis procera Small tree 

Canna bidentata Herb 

Capsicum frutescens Under shrub 

Carpolobia lutea Shrub 


Cassia fistula Small tree 

Cassia obtusifolia Small tree 

Chassalia kolly Shrub 

Chromolaena odorata Shrub 

Cissampelos owariensis Climber 

Cleome ciliata Herb 

Clerodendronumbellatum Shrub 

Cnestis furruginea Climber 

Cnestis longiflora Climber 

Coix lacryma-jobi Grass 

Cola acuminata Tree 

Cola millenii Tree 

Cola nitida Tree 

Combretum racemosum Shrub 

Crotalaria retusa Herb 

Soladoye et al. 559 

Culcasia scandens Climbing herb 

Cymbopogon citratus Grass 

Deinbollia pinnata Small tree 

Dichapetalum 

madagascariense 

Shrub/tree 

Dioclea reflexa Climber 

Dombeya buettneri Shrub/smalltree 

Duranta repens Shrub 

Elaeis guineensis Tree 

Eleusine indica Grass 

Emilia coccinea Herb 

Eugenia jambos Small tree 

Eugenia malaccensis Tree 

Euphorbia heterophylla Herb 

Euphorbia hirta Herb 

Ficus benjamina Tree 

Ficus exasprata Tree 

Ficus mucuso Tree 

Ficus sur Small tree 

Funtumia africana Tree 

Gossypium barbadens Shrub 

Grewia carpinifolia Shrub 

Harungana 

madagascariensis 

Tree 

Hedranthera bateri Shrub 

Hippocratea velutina Shrub 

Icacina tricantha Shrub 

Indigofera macrophylla Shrub 

Ipomea mauritiana Climber (liane) 

Ixora coccinea Shrub 

Jatropha curcas Shrub



Jatropha gossypifolia Shrub 

Jussiae abyssinica Herb 

Landolfia dulcis var. barteri Climber 

Lantana camara Woody herb 

Lecaniodiscus cupanoides Shrub 

Leptoderris micrantha Shrub 

Luffa cylindrica Climber 

Macrosphyra longistyla Shrub 

Malacantha alnifornia Tree 

Malvestrum 

coromandelianum 

Woody herb 

Mangifera indica Tree 

Manihot glaziovii Shrub 

Mariscus alternifolius Sedge 

Microdesmis puberula Small tree 

Milicia exelsa Tree 

Mimosa pudica Shrub 

Morinda lucida Tree 

Morinda morindoides Shrub 

Musanga cecropioides Tree 

Mussaenda elegans Shrub 

Myrianthus arboreus Tree 

Napoleona imperialis Small tree 

Nauclea latifolia Small tree 

Newbouldia laevis Tree 

Olax subscorpioidea Small tree 

Oxyanthus formusus Tree 

Passiflora foetida Twining herb 

Paullinia pinnata Woody climber 

Peltophorum pterocarpum Tree 

Phllanthus amarus Herb 

Physalis angulata Annual herb 

Platycerum alcicorne Fern allies 

Pleioceras barteri Shrub 

Polyalthia longiflora Tree 

Psidium guajava Small tree 

Quisqualis indica Shrub 

Rauvolfia vomitora Small tree 

Ricinodendron heudelottii Tree 

DISCUSSION 


Rothmannia longiflora Small tree 

Rytigynia umbellulata Shrub 

Sabicea calycina Shrub 

Salacia pallescens Shrub 

Scoparia dulcis Shrub 

Securinega virosa Shrub 

Sida acuta Shrub 

Smilax kraussiana Shrub 

Solanum torvum Shrub 

Sphenocentrum jollyanum Shrub 

Stachytarpheta 

cayennensis 

Shrub 

Stachytarpheta indica Herb 

Stachytarpheta mutabilis herb 

Synsepalum dulciferum Small tree 

Talinum triangulare Herb 

Terminalia randii Tree 

Thaumatococcus daniellii Herb 

Trema orientalis Small tree 

Triclisia subcordata Woody climber 

Tridax procumbens Low herb 

Triplochiton sclerexylon Tree 

Tristemna incompletum Shrub 

Triumphetta cordifolia Shrub 

Triumphetta rhomboidea Shrub 

Urena lobata Woody shrub 

Vernonia amygdalina Small tree 

Voacanga Africana Tree 

Waltheria indica Herb 

The disappearance of many plant species due to human 

activities is depleting the world’s genetic resources and is 

putting man’s heritage of biodiversity under serious 

threat. There is therefore the urgent need to preserve 

genetic diversity including plant resources of known and 

unknown economic importance which will guarantee the 

availability of all potentials for use in the benefit of our 

children and grandchildren (Olowokudejo,

Number of species 

60 

50 

40 

30 

20 

10 

0 

trees Shrubs climbers 

herbs 

sedges 

grasses 

Figure 2. Chart showing the percentage distribution of plants in 

relation to their habit. 

Number of species 

140 

120 

100 

80 

60 

40 

20 

0 

monocots 

Monocots Dicots 

Figure 3. Chart showing the distribution of plant species 

in relation to their major plant groups 

1987). The human race in their quest for economic 

development and improvement of their conditions of life 

must come to terms with the realities of resource 

limitations and the carrying capacity of ecosystem must 

also take account of the needs of future generation. This 

Soladoye et al. 561 

is the central message to modern conservation. 

Biological diversity must be treated seriously as a global 

resource, be indexed, used and above all preserved. 

Three circumstances make it imperative for this to be 

given an unprecedented urgency particularly in West 

Africa. Firstly, exploding human populations are seriously 

degrading the environment at an alarming rate in the sub 

region. Secondly, science is discovering new uses for 

biological diversity in ways that relieve both human 

suffering and environmental destruction. Thirdly, much of 

the diversity is being irreversibly lost through extinction 

caused by the destruction of natural habitats, which 

occurs more in Africa than elsewhere (Wilson, 1988). 

Dasmana et al., (1973) agreed that forest exploitation 

leads to the extinction of animals and plants whose 

genetic resources are of considerable value to future 

generations (Round Table, 1969). Forest depletion has 

destabilized the natural environment and eroded genetic 

resources throughout the southern part of Nigeria in 

order to meet the sustenance of the population and 

financial requirements of government i.e. the social, 

economic, demographic and political needs of the 

people. Exploitation of forests therefore appears to be 

inevitable considering the above. Opinions are however 

split about vegetation depletion which is considered as a 

loss of natural heritage. According to some scientists 

(Harvey and Hallet, 1977) it may not be beneficial to 

conserve resources for future generation at all costs 

because the future demands, aspirations, lifestyles and 

needs of rural people cannot be adequately defined now. 

Must we then wait for the needs to be defined before we 

conserve? Definitely not because all of these genetic 

resources would have disappeared before the needs are 

identified. As such, conservation is basic to human 

welfare and indeed to human survival (Allen, 1980). Lack 

of conservation measures will amount to an increase in 

the number of endangered species and this will 

ultimately result in extinction, which is the gradual but 

sure elimination of taxa (Allaby, 1998). Many of the 

species that are already endangered are faced with the 

risk of eventual extinction if human activities such as land 

development, logging and pollution are not checked. 

Gbile et al. (1981, 1984) revealed that about four 

hundred and eighty plant species of the Nigerian flora 

have been described as endangered or rare, out of which 

many of these are being studied at the Forestry 

Research Institute of Nigeria, Ibadan. Apart from the 

gradual loss of biodiversity, the devastating 

environmental disasters in urban and rural areas of 

Nigeria indicate that these environments are under stress 

and require urgent intervention (Oguntala, 1993). 

Exploitation of forest around the permanent site of the 

University continues unabated. Encroachment on 

University land stopped since 1982 allowing for the 

vegetation to revert to climatic climax status. The forest 

of the University at present serves as a refuge for both 

plants and animals especially birds and games escaping


from local hunters. While developmental activities 

continue on the campus it will be a sound scientific 

judgment to protect a representative sample of 

vegetation for posterity. This is the practice in most 

developed countries of the world. The International 

Institute for Tropical Agriculture (IITA) at Ibadan, Nigeria 

has such an area which now serves as an example of a 

typical tropical Rain forest in south Western Nigeria. 

REFERENCES 

Allen R (1980). How to save the World: Strategy for World 

conservation. Kogan Page Limited. London. 

Allaby M (1998). Oxford dictionary of plant Sciences. Oxford University 

Press, Oxford. 

Dasmana RF, Milton J, Freeman PH (1973). Ecological Principles for 

Economic Development. John Wiley & Sons Limited. p. 252 

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