Tariq Stévart

Missouri Botanical Garden · Africa and Madagascar

Introduction. In recent decades, Madagascar has become one of the most important plant hotspots in the world. The country's remaining forests and vegetation are disappearing at an alarming rate, while dozens of new species are discovered each year. Amongst the plant families that have long been studied, Orchidaceae appear as one of the most charism...

The Checklist of the Vascular Plants of the Republic of Guinea (CVPRG) is a specimen-based, expert-validated knowledge product, which provides a concise synthesis and overview of current knowledge on 3901 vascular plant species documented from Guinea (Conakry), West Africa, including their accepted names and synonyms, as well as their distribution...

Microcoelia and the monospecific Taeniorrhiza and Chauliodon are notable among Afrotropical angraecoid orchids for being leafless. However, the affinity among these genera was not addressed in previous molecular phylogenetic studies, thus precluding the understanding of how many times has leaflessness evolved in angraecoids. The discovery of an add...

Introduction. In recent decades, Madagascar has become one of the most important plant hotspots in the world. The country's remaining forests and vegetation are disappearing at an alarming rate, while dozens of new species are discovered each year. Among the plant families that have long been studied, Orchidaceae appear as one of the most charismat...

Background and aims – Podostemaceae is a family of strictly aquatic plants found in rapids and waterfalls. Despite a recent treatment in the Flore du Gabon, the family remained poorly known, with no major studies including Gabonese collections, and almost no targeted inventories since 1966. We present the first large-scale inventory of this family...

A synopsis of Tridactyle Schltr. (Orchidaceae) in São Tomé and Príncipe is presented. We recognize nine species in São Tomé and Príncipe, including four new species. We describe here T. amadorii D’haijère, T. cocophila D’haijère, T. levelevis D’haijère & Stévart, and T. oboensis D’haijère & Stévart. Tridactyle armeniaca (Lindl.) Schltr., recorded b...

The oceanic islands of the Gulf of Guinea display a large diversity of environmental conditions and biological communities, whose interactions have contributed to the development of a great variety of ecosystems, from mangroves to montane grasslands. Human activities have extensively and profoundly altered many of these natural ecosystems over the...

The oceanic islands of the Gulf of Guinea (Príncipe, São Tomé, and Annobón) are an exceptional centre of endemism for flora and fauna. Remarkable progress has been made in biological research during the last few decades: from species being described and reported for the first time, to general patterns of species-habitat associations found across te...

Despite a long history of botanical collecting in the three oceanic islands of the Gulf of Guinea, no recent studies have documented floristic patterns. This chapter summarizes information on the vascular plants of the islands, including inventories conducted on Príncipe and São Tomé since 2017, as well as two recent expeditions to Annobón. An upda...

In this data paper, we present a specimen-based occurrence dataset compiled in the framework of the Conservation of Endemic Central African Trees (ECAT) project with the aim of producing global conservation assessments for the IUCN Red List. The project targets all tree species endemic or sub-endemic to the Central African region comprising the Dem...

Cyrtorchis, a Tropical African angraecoid orchid genus, is renowned for its showy white stellated long-spurred flowers, which challenge species delimitation and resulting taxonomy. Also, the genus appears sphingophilous, and constitutes a suitable model for studies on reproductive biology of Angraecoids, a first step to their conservation.

We propose a floristic description of the montane savannas of the Nimba, an interpretation in terms of ecosystem typology, and a discussion on the spatial distribution and geomorphology, based on a discussion of the literature and vegetation plots surveyed during a field visit. The dynamics of the different types of savannas is then discussed and a...

Aim Oceanic islands have played an important role in our understanding of the diversification of organisms, and phylogenetic estimates have been used in this context to investigate the origin of island diversity and its relationship to the continent. Using a typical orchid genus rich in island endemics and with widespread continental relatives, we...

Endemism is one of the most important concepts in biogeography and is often used to guide biodiversity conservation, yet our understanding of the determinants of endemism in many biodiverse tropical regions is limited. This is true for western Central Africa, a region with one of the highest levels of plant diversity in tropical Africa, where endem...

Background and objectives—Podocarpus latifolius (synonym of P. milanjianus) is a key tree representative of Afromontane forests where it is highly threatened by climate and land-use changes. While large populations occur in East Africa, only a few isolated and usually small populations remain in western Central Africa (Cameroon to Angola). Studying...

Allexis obanensis has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Allexis obanensis is listed as Endangered under criteria B2ab(i,ii,iii,iv,v).

Allophylus imenoensis has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Allophylus imenoensis is listed as Endangered under criteria B2ab(iii).

Aphanocalyx pectinatus has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Aphanocalyx pectinatus is listed as Endangered under criteria B2ab(iii).

Allophylus mayimbensis has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Allophylus mayimbensis is listed as Endangered under criteria B2ab(iii).

Allophylus ngounyensis has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Allophylus ngounyensis is listed as Endangered under criteria B2ab(iii).

Allophylus poungouensis has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Allophylus poungouensis is listed as Vulnerable under criteria B2ab(i,ii,iii,iv,v).

Chaetocarpus gabonensis has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Chaetocarpus gabonensis is listed as Vulnerable under criteria B1ab(iii)+2ab(iii).

Aulacocalyx pallens has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Aulacocalyx pallens is listed as Vulnerable under criteria B2ab(i,ii,iii,iv,v).

Aulacocalyx pallens subsp. letestui has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Aulacocalyx pallens subsp. letestui is listed as Vulnerable under criteria B2ab(iii).

Crateranthus letestui has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Crateranthus letestui is listed as Vulnerable under criteria B2ab(iii).

Crateranthus congolensis has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Crateranthus congolensis is listed as Endangered under criteria B2ab(iii).

Dactyladenia gilletii has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Dactyladenia gilletii is listed as Vulnerable under criteria B2ab(ii,iii,iv,v).

Memecylon biokoense has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Memecylon biokoense is listed as Endangered under criteria B1ab(iii)+2ab(iii).

Magnistipula cupheiflora subsp. cupheiflora has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Magnistipula cupheiflora subsp. cupheiflora is listed as Vulnerable under criteria B2ab(iii).

Pavetta owariensis var. opaca has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Pavetta owariensis var. opaca is listed as Vulnerable under criteria B2ab(i,ii,iii,iv,v).

Polyscias letestui has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Polyscias letestui is listed as Endangered under criteria B2ab(iii).

Raphia gabonica has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Raphia gabonica is listed as Endangered under criteria B2ab(iii).

Syzygium gilletii has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Syzygium gilletii is listed as Vulnerable under criteria A3c.

Rinorea ebolowensis has most recently been assessed for The IUCN Red List of Threatened Species in 2020. Rinorea ebolowensis is listed as Vulnerable under criteria B2ab(i,ii,iii,iv,v).

Citation: Stévart, T., Pauwels, O.S.G. & Vande weghe, J.P. 2021. Chapter 11. Conservation. Pp. 316-323 in: Vande weghe, J.P. & Stévart, T. (eds). The Ogooué Delta. Missouri Botanical Garden Press, Saint Louis: 328 pp.

Citation: Stévart, T., Pauwels, O.S.G. & Vande weghe, J.P. 2021. Introduction. Pp. 10-17 in: Vande weghe, J.P. & Stévart, T. (eds). The Ogooué Delta. Missouri Botanical Garden Press, Saint Louis: 328 pp.

Background and aims-A recent taxonomic and molecular study of the genus Cyrtorchis revealed three new species. Here, we describe one of these new species, endemic to the Cameroon Volcanic Line (CVL), and compare it to its closest relatives. Its conservation status is provided along with detailed information on its ecology and reproductive biology....

Over the last several years, the IUCN Red List approach for assessing the risk of extinction faced by species has been adapted into a Red List of Ecosystems methodology. This endeavor faces several important challenges, including how to define the types of ecosystems to which the Red List criteria are applied, and how to manage information on the g...

Here we describe and illustrate two new species of angraecoid orchids from East Africa, Tridactyle delepierrei and Ypsilopus iversenii, respectively from Albertine Rift (Rwanda and Uganda) and west Usambaras (Tanzania). The first species is closely allied to the three species of Tridactyle sect. Eggelingiae and to Tridactyle nalaensis. The second s...

The genus Cyrtorchis is renowned for its conspicuous white, long‐spurred flowers, but also for its challenging problems of species delimitation due to the great morphological resemblance of their flowers. Based on a preliminary visual inspection of 1752 specimens, 27 morphogroups were defined including 6 unpublished taxa. Then, we used a representa...

The High Conservation Value (HCV) concept, developed by the Forest Stewardship Council to promote sustainable forest management, is widely employed for certification of forestry and agriculture concessions, and has been adopted by many logging and palm oil companies. HCV criterion 1, which deals with “endemic, and rare, threatened or endangered spe...

Eugenia ogoouensis is a small tree up to 5 cm in diameter, known from mature or secondary terra firme forest, riverside forest, flooded forest, and swamp forest, between 10 and 110 m in elevation. The species is endemic to Gabon and is known from 22 collections, the oldest three of which were made in 1912 by Fleury in the vicinity of Nkogo in the O...

Cassipourea dinklagei is a small shrub up to 2.5 m high, known from terra firme forest, exploited or mature, or from wet valley bottoms, rarely swampy. One collection was made in the coastal forest. Its known altitudinal amplitude is 20 to 65 m. The species is probably endemic to Cameroon. Six collections from Gabon have been identified as belongin...

Warneckea macrantha is a large tree up to 30 m tall, known from periodically inundated forests near rivers, between 10 and 130 m in elevation. The species is endemic to Central Africa, occurring in Gabon and the Republic of the Congo. It is known from 12 collections, of which 11 were made in Gabon and one in the Republic of the Congo. It has first...

Magnistipula devriesii is a shrub or a small tree, up to 6 m tall, known from mature and secondary terra firme forest between 100 and 150 m in elevation. The species is endemic to Gabon and is known from two collections made by Breteler in 1994 in the region of Ndjolé (Moyen-Ogooué), about 10 km and 20-30 km north-northwest of the city, thus repres...

Rothmannia jollyana is a treelet up to 5 m high, known from the undergrowth of terra firme forest, between 300 and 600 m in elevation. The species is endemic to Central Africa, occurring in Gabon, the Republic of the Congo, and Angola (Cabinda). It is known from seven collections made between 1876 and 1987, of which one was collected by Soyaux in 1...

Memecylon salicifolium is a small tree, known from terra firme forest and edge of the savannah, between 400 and 600 m in elevation. The species is endemic to Gabon and is known from five collections from three localities: Bélinga (Ogooué-Ivindo) in the north-eastern part of the country (Hallé 566; 2919; 3824, collected in 1964 and 1966), Ndjolé (Mo...

Polyscias aequatoguineensis is a shrub or a small tree up to 6 m tall, known from inselbergs, at the edges of exposed rocks, between 600 and 800 m in elevation. The species is endemic to Atlantic Central Africa, occurring in Gabon and Equatorial Guinea. It is known from eight collections, of which five (three occurrences) were made between 1998 and...

Lychnodiscus brevibracteatus is a tree up to 20 m high and up to 50 cm in diameter, known from terra firme forest, and sometimes in swamp forest, between 100 and 300 m in elevation. The species is endemic to Central Africa occurring in Gabon and Cameroon. It is known from six collections, of which four were made in Gabon between 1925 and 2007 and t...

Memecylon mouririoides is a tree up to 20 m high and 45 cm in diameter, known from mature terra firme forest, between 200 and 300 m in elevation. The species is endemic to Gabon and is known from two collections, of which one was made by Le Testu in 1924 between Guidouma and Saint-Croix (Ngounié province), and one by Reistma in 1985 in the Moukalab...

Pauridiantha pleiantha is a tree up to 12 m high, known from terra firme forest, between 100 and 400 m in elevation. The species is endemic to Gabon and is known from six collections from the Moukalaba-Doudou National Park area (Ogooué-Maritime and Nyanga province). These six collections represent six occurrences and one subpopulation. Considering...

Pauridiantha smetsiana is a tree up to 7 m high, known from terra firme forest, between 20 and 100 m in elevation. The species is endemic to Gabon and is known from 20 collections and 1 human observation, of which 19 were made between 1990 and 2014 in the region of Rabi in the Ogooué-Maritime province. Two other collections were made in 1991 in the...

Rhaptopetalum rabiense was preliminarily assessed according to the IUCN Red List Categories and Criteria as part of the publication of the species by Kenfack and Nguema in 2019 as Critically Endangered. However, this evaluation was not published on the IUCN website. We hereby propose an update of this assessment. Rhaptopetalum rabiense is a tree u...

Rinorea apertior is a shrub or a small tree up to 7 m high, known from secondary terra firme forest, between 30 and 110 m in elevation. The species is endemic to Gabon and is known from 11 collections, of which seven were made between 1989 and 1995 in the region of Rabi in the Ogooué-Maritime province. Two others were made in 2011 by Maas in the re...

Cleistanthus bambidianus is a non timber tree up to 20 m high known from mature forests up to 500 m elevation. The species is endemic to Gabon and known from 12 collections made in the Ogooué Ivindo province (south of Ayem; Forêt des Abeilles; and twice in CFAD Rougier Ivindo) and in the Ogooué-Lolo province (five times NE of Lastourville; at Koula...

Englerodendron triplisomere is a small rainforest tree up to 9 m tall and 7 cm dbh, known from lowland and submontane terra firme forests, and found between 50 and 1,000 m elevation. It is morphologically separated from other Englerodendron spp. by leaves 2-jugate, rarely 1-jugate or unifoliolate, but then 2-jugate leaves also present; sepals with...

The species has been assessed as VU D2 by the World Conservation Monitoring Centre in 1998. These assessors only included the type collection known from a forested area around Tchibanga in Gabon, and mentioned that the species may be more widespread given that the country's forests are relatively unexplored. However, they considered that many fores...

Englerodendron hallei is a small tree up to 7 m height, known from mature terra firme forests and riverside forests, between 5 and 500 m elevation. The species is endemic to Gabon and known from 17 herbarium collections and four human observations, that were mainly collected/observed in the Estuaire province (16 collections and the four human obser...

Craibia macrantha is a tree up to 20 m high found in lowland forest, between 350─460 m elevation. The species occurs in Gabon and in the Republic of the Congo. It is known from four collections representing four occurrences, of which three were made in Gabon by Le Testu (7992) in 1930 near the city Koulamoutou, by Breteler (14795) in 1999 east of t...

This paper argues that the conceptualization of the interplay of 'natural' and 'anthropogenic' influences in shaping tropical forest landscapes is hindered by a debate between two opposing concepts and their supporters: 'disturbance' versus 'domestication'. The former is the standard concept in ecology, wherein anthropogenic influences are seen as...

Angraecoid orchids present a remarkable diversity of chromosome numbers, which makes them a highly suitable system for exploring the impact of karyotypic changes on cladogenesis, diversification and morphological differentiation. We compiled an annotated cytotaxonomic checklist for 126 species of Angraecinae, which was utilised to reconstruct chrom...