An Annotated Checklist of the Vascular Flora of Guinea-Bissau (West Africa)
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BLUMEA 53: 1– 222 Published on 29 May 2008 http://dx.doi.org/10.3767/000651908X608179 AN ANNOTATED CHECKLIST OF THE VASCULAR FLORA OF GUINEA-BISSAU (WEST AFRICA) L. CATARINO, E.S. MARTINS, M.F. PINTO BASTO & M.A. DINIZ IICT – Instituto de Investigação Científica Tropical, Trav. Conde da Ribeira 9, 1300-142 Lisboa, Portugal; e-mail: [email protected] CONTENTS Summary . 1 Résumé . 1 Resumo . 2 Introduction – The country’s main features . 2 Vegetation . 5 Botanic collections in Guinea-Bissau . 9 Material and Methods . 13 Checklist of the vascular flora of Guinea-Bissau . 19 Pteridophyta . 19 Magnoliophyta (Angiospermae) . 21 Magnoliopsida (Dicotyledones) . 21 Liliopsida (Monocotyledones) . 119 References . 151 Taxonomic Index . 191 SUMMARY A Checklist of Guinea-Bissau’s vascular flora is presented, based on the inventory of herbarium material and on recent collections. In addition to the name, we cite for each taxon the basionym and synonyms, the life form and habitat, as well as the chorology, Raunkiaer’s biological type, phenology and vernacular names if known. 1507 specific and infra-specific taxa were recorded, of which 1459 are autochthonous, belonging to 696 genera. This shows a higher diversity than the 1000 species estimated so far. In the autoch- thonous flora there are 22 species of Pteridophyta from 14 families; 1041 taxa of Dicotyledons from 107 families, and 396 taxa of Monocotyledons belonging to 33 families. Three taxa are probably endemic to the country. Key words: flora, phytogeography, ecology, chorology, vernacular names, Guinea-Bissau. RÉSUMÉ Ayant pour base l’inventaire des matériaux d’herbier et les récoltes récentes, une Checklist est présenté sur la flore vasculaire de la Guinée-Bissau. Au-delà du nom, basionyme et synonymes pour la région, il est rapporté, pour chaque taxon recensé dans le pays, l’habitus, les habitats, la chorologie, le type biologique de Raunkiaer, la phénologie et les noms vernaculaires si connus. © 2008 Nationaal Herbarium Nederland, Leiden University branch 2 BLUMEA — Vol. 53, No. 1, 2008 1507 taxons spécifiques et infraspécifiques de plantes vasculaires, desquelles 1459 autochtones, appartenant à 696 genres on été recensées, nombre largement supérieur par rapport au millier d’espèces estimées jusqu’à présent. Dans la flore autochtone on compte 22 espèces de Pteridophytes, appartenant à 14 familles, 1041 taxons de Dicotylédones, de 107 familles et 396 taxons de Monocotylédones, appartenant à 33 familles. Trois taxons sont probablement endémiques au pays. Mots clés: flore, phytogéographie, écologie, chorologie, noms vernaculaires, Guinée-Bissau. RESUMO Com base na inventariação dos materiais de herbário e nas colheitas recentes, é apresentada uma Checklist da flora vascular da Guiné-Bissau. Além do nome, basiónimo e sinónimos para a área, são referidos para cada taxon recenseado no país o hábito, habitats onde foi encontrado, corologia, tipo biológico de Raunkiaer, fenologia e nomes vernáculos conhecidos. Recensearam-se 1507 taxa específicos e infraespecíficos de plantas vasculares, dos quais 1459 autóctones, pertencentes a 696 géneros, número largamente superior ao milhar de espécies até agora estimado. Contabilizaram-se na flora autóctone 22 espécies de Pteridófitos, pertencentes a 14 famílias, 1041 taxa de Dicotiledóneas, de 107 famílias e 396 grupos taxonómicos de Monocotiledóneas, pertencentes a 33 famílias. São referidos três taxa provavelmente endémicos no país. Palavras chave: flora, fitogeografia, ecologia, corologia, nomes vernáculos, Guiné-Bissau. INTRODUCTION THE COUNTRY’S MAIN FEATURES Guinea-Bissau is located in the Northern Intertropical Zone of West Africa, between 10°59' – 12°20' north and 13°40' – 16°43' west, having a surface area of 36,125 km2. It is bordered by the Republic of Senegal to the north, the Republic of Guinea to the east and south and by the Atlantic Ocean to the west (see Fig. 1). The country includes a continental mainland and a group of 40 islands, the Bijagós Archipelago, not far from the continent. There are also some other islands separated from the continent only by narrow sea straits, such as Bolama, Pecixe and Melo. Geomorphology The geomorphology of the Guinean territory shows a smooth relief, with most of the land below 50 m altitude. The coastal zones are mainly lowlands. With the high tide range occurring here, reaching up to 6 m, extensive areas in the coastal zones remain exposed to the daily tidal effect. Most of the inner centre and north-eastern parts of the country are occupied by scarcely raised plains, where the altitude does not surpass 100 m. The inner south-eastern region is the hilliest region of the country but the Boé Hills, the most raised part of their territory, only reach 298 m altitude (Mota 1954). The islands of the Bijagós Archipelago show a morphology similar to the mainland, with a sinuous shoreline and low altitudes. The hydrographic network is complex and extensive. In addition to the climate, it is conditioned by the levelling of the territory and by the marine transgression (Ribeiro 1950; Teixeira 1962). Low altitudes in a large portion of the territory allow flooding of extensive areas in the river banks and coastal plains, which can remain flooded during the rainy season and even several weeks after its end. The same occurs often in lowland inner plains with slow superficial drainage and impermeable soils. L. Catarino et al.: Checklist of the vascular flora of Guinea-Bissau 3 Fig. 1. Map of Guinea-Bissau showing the limits of the four regions considered. (B – Bijagós Ar- chipelago; E – East; N – North; S – South) Because water flow has a strong dependence on rainfall, the fresh watercourses show a seasonal flow regime, classified as tropical pluvious (Costa 1946). As a consequence most of the streams and some rivers dry up by the end of the dry season. There are a few permanent fresh watercourses in the country with the Corubal, Farim and Geba being the most important rivers. Most of the locally called rivers are in fact estuaries and inlets, which penetrate deeply in the continental territory due to the plain relief. In addition to the rivers, there are some small lakes in the country, namely in the southern and eastern regions. Temporary pools with variable sizes, locally called vendus, are common in the south-east (Alves 2000). Climate Without geomorphologic features sufficiently marked to influence it, the climate in Guinea-Bissau depends mainly on its geographic position between the tropics. The climate, and particularly the rain regime, is conditioned by the seasonal migration of the Intertropical Convergence Zone (ITCZ). In the dry season, from November to May, the ITCZ is positioned to the south of the territory, which is under the influence of continental, dry air masses coming from the north-east or north (McGregor & Nieuwolt 1998). When the ITCZ, in its yearly movement from south to north reaches the territory, the rainy season begins. The rains start usually in late May or early June, advance from south-west to north-east and last during the length of time in which the ITCZ is over or has moved to the north of the country. The rainy season usually ends in late October, when the ITCZ returns south. Annual rainfall is the climatic factor that shows the largest differences in the country, 4 BLUMEA — Vol. 53, No. 1, 2008 decreasing from 2400–2600 mm in the south-west to 1200–1400 mm in the north-east (Machado 1972). The differences in temperature between regions are small: the annual means vary from 25.9 to 27.1 °C and the mean annual temperature in the country is around 26.5 °C. There are two annual maxima and minima in the air temperature: by the end of the dry season, in April or May, there is a primary maximum and in October or November a secondary one. The mean minimum temperatures have a primary minimum in the December or January and a secondary one in August, in the rainy season. The annual thermal ranges are also low: the differences between the annual minimum and maximum averages vary from 7.0 to 14.7 °C which is greater in the eastern inner region (Costa & Resende 1994). The relative humidity shows large seasonal variations related to the rain regime and the prevailing winds. Their annual means vary from 69 to 79%. Hayward & Oguntoyinbo (1987), in a classification of the climatic regions in West Africa locate the country in zone 7 West, characterized by rains from June to November, with a peak in August, annual rainfall from 1500 to 2000 mm and the higher annual temperatures occurring in April–May. According to Fosberg et al. (1961) only the coastal part of the country is included in the humid tropics. Soils As most tropical soils, the greater part of Guinea-Bissau soils are poor both in organic matter and ion exchange bases. The most representative soil groups in the country are Ferralsols, Plinthosols, Gleysols, Fluvisols and Arenosols. There are other substrates that cannot be considered as soils, such as lateritic cuirasses and mud deposits (Teixeira 1962; FAO-ISRIC-ISSS 1998). Ferralsols – deep soils with a sandy or sandy-clayish texture, are very common all over the country. The soils of this group are quite poor in nutrients and organic matter and, according to the topographic position can have red, orange, yellow or grey colours. The natural vegetation in these soils is mainly woodland and savannah woodland, as well as forest in the south-west of the country. Most of the country’s agriculture is done on this kind of soils. Plinthosols – mineral soils that show, at small deepness, layers of lateritic materials more or less consolidated. These soils occur in a greater extent in the inner part of the country, and particularly in the south-east and are occupied mostly by woodland and savannah woodland.