[Botany • 2025] Keetia magassoubiana (Rubiaceae: Vanguerieae) • A threatened evergreen forest Climber and an updated key to Keetia in West Africa

Keetia magassoubiana Cheek, 

 

in Cheek, Yasuda, Jongkind et Bowden-Pickstock, 2025.

DOI: doi.org/10.1007/s12225-024-10234-z

Summary

Keetia magassoubiana Cheek, an evergreen rainforest climber, is described and illustrated from the Republic of Guinea, Sierra Leone, Liberia and Ivory Coast. Previously indicated as being close to, but different from, K. tenuiflora (Hiern) Bridson, it differs in the glossy, black, glabrous, epidermis of the distal stem internodes; the first internode rarely with very sparse, red adpressed hairs (vs epidermis pale white-brown, with dense, pale yellow, spreading hairs); abaxial leaf surfaces with domed domatia with a central aperture (vs domatia absent or obscure); secondary stem leaf bases acute (vs obtuse to truncate); bracts forming a laciniate sheath on the distal peduncle (vs two opposite triangular bracts) and the pyrene surface honeycombed with pits (vs entire). The species was earlier included within Canthium multiflorum (Schum. & Thonn.) Hiern, now K. multiflora (Schum. & Thonn.) Bridson, in the Flora of West Tropical Africa, second edition. An updated key is presented to the 16 species of the genus from West Africa. Keetia magassoubiana is provisionally assessed using the IUCN standard as Endangered [EN B1ab(iii)] due to only five of the recorded 14 locations having extant forest habitat, and because of ongoing threats of habitat clearance, mainly for agriculture but also for mining.

Key Words: Conservation, extinction, liana

Keetia magassoubiana Cheek sp. nov.

Recognition. Keetia magassoubiana Cheek sp. nov. is close to but differs from K. tenuiflora in the glossy, black, glabrous epidermis of the distal stem internodes, rarely with very sparse red hairs (vs epidermis pale white-brown, densely pale yellow hairy in K. tenuiflora), abaxial leaf surface with domatia domed, with a central aperture (vs domatia absent or obscure), the secondary stem leaf bases acute (vs obtuse to truncate), the bracts forming a laciniate sheath on the distal peduncle (vs two opposite triangular bracts) and the pyrene surface honeycombed with pits (vs smooth).

Etymology. Named for Dr Sekou Magassouba, Director-General of the National Herbarium of Guinea (HNG) in the University of Gamal Abdel Nasser – Conakry, Republic of Guinea. Under his careful, tireless and diligent administration, HNG has increased greatly in its capacity to devise and manage projects, attract grants, to train students, including now at doctorate level for the first time and to develop publication of research and publicise the conservation of the threatened plant species and habitats of his country.

Martin Cheek, Shigeo Yasuda, Carel C. H. Jongkind and Joel Bowden-Pickstock. 2025. Keetia magassoubiana sp. nov. (Rubiaceae - Vanguerieae), a threatened evergreen forest climber and an updated key to Keetia in West Africa. Kew Bulletin. DOI: doi.org/10.1007/s12225-024-10234-z

[Botany • 2024] Voacanga madureirae (Apocynaceae: Tabernaemontaneae) • A New Species from Atlantic Central Africa

Voacanga madureirae  Paiva, O.Lachenaud & Covelo,

in Lachenaud, Paiva, Covelo, Cheek et Onana. 2024. 

DOI: 10.1007/s12225-024-10179-3 

 twitter.com/KewBulletin

photos by Quentin Luke and Maria Do Céu Madureira.

Summary

A new species of Apocynaceae from Atlantic Central Africa, Voacanga madureirae Paiva, O.Lachenaud & Covelo, is mapped, described and illustrated. It occurs on the Gulf of Guinea islands of Príncipe (São Tomé and Príncipe) and Bioko (Equatorial Guinea) and in the highlands of western Cameroon. The new species differs from other African Voacanga by its calyx distinctly exceeding the corolla (vs shorter or at most equalling it). It is further separated from V. chalotiana Pierre ex Stapf by the presence of a row of colleters in the upper half of the calyx (not near the base) and from other Central African species by its syncarpous fruits and almost straight (not strongly twisted) corolla tube. It is assessed as Near Threatened according to IUCN criteria.

Key Words: Bioko, Cameroon, Equatorial Guinea, Gulf of Guinea islands, São Tomé and Príncipe, Tabernaemontaneae.

Voacanga madureirae. A flowers, Q. Luke 13274; B fruit, M. C. Madureira & Equipa Proj. Pagué III 87; C fruit cut in two halves, showing the inside, M. C. Madureira & M. Sebastião 3 MCM.

photos: A Quentin Luke, B – C Maria Do Céu Madureira.

Voacanga madureirae Paiva, O.Lachenaud & Covelo sp. nov. 

RECOGNITION. Voacanga madureirae is easily recognised by its syncarpous fruits, its almost straight (not strongly twisted) corolla tube, and its calyx distinctly exceeding the corolla and bearing inside a dense row of colleters in the upper half of the tube. The first two characters are also found in V. chalotiana Pierre ex Stapf, which, however, has a smaller calyx, bearing a row of colleters near the base and much exceeded by the corolla. All other Central African species of Voacanga have apocarpous fruits, strongly twisted corolla tubes and a corolla usually exceeding the calyx, or equalling it in V. diplochlamys K.Schum., which, however, has puberulous stems and inflorescence while these parts are glabrous in V. madureirae.

 

Olivier Lachenaud, Jorge Paiva, Filipe Covelo, Martin Cheek and Jean Michel Onana. 2024. Voacanga madureirae (Apocynaceae), A New Species from Atlantic Central Africa. Kew Bulletin. DOI: 10.1007/s12225-024-10179-3

  twitter.com/KewBulletin/status/1771440378882777419

[Botany • 2020] Gymnosiphon mayottensis (Burmanniaceae) • A New Species from Mayotte, Comoro Islands

Gymnosiphon mayottensis Cheek,

in Cheek et Traclet, 2020. 

 sciencepress.MNHN.fr/en/periodiques/adansonia/42/8

 Photos: Guillaume Viscardi, Étienne Vennetier.

A new species of Gymnosiphon Blume (Burmanniaceae), G. mayottensis Cheek, sp. nov. is formally described from Mount Bénara and Mount Mtsapéré on the island of Mayotte in the Comores. This is the first named species of the genus published from the Comoro Islands. The new species resembles G. longistylus (Benth.) Hutch. in the six long, filamentous, stigma appendages, two arising from each of the three styles, also in the absence of an underground tuber or thickened rhizome; it differs in that the bracts are appressed to the rhachises, and about equal in length to them (not patent, and < 1/4 as long), the outer tepals turn rapidly from white to translucent at anthesis (not remaining white), the inner perianth lobes are absent (not present and conspicuous), the stigmas are broader than long, held horizontally and are united along their lateral margins (not longer than broad, pendulous, free from each other along their lateral margins). The new species is known from two forest sites, both with threats, and less than 50 individuals are known. Accordingly, it is assessed as Critically Endangered (B1ab(i-iv), B2ab(i-iv), D) using the IUCN 2012 standard. The new species is illustrated by colour photos and line drawings, and mapped.

KEYWORDS: Achlorophyllous, mycotrophs, Africa, Madagascar, saprophytes, threatened, new species

 Gymnosiphon mayottensis Cheek, sp. nov.:
 A, habit; A', detail showing base of stem and roots; B, branch of inflorescence with flower buds and detail of bract; C, dissection of large flower bud from B; D, open flower; E, perianth and stigmas (from photo); F, stamen and pair of lateral outer perianth lobes from bud dissected in C; G, stigmatic filament looped

 Gymnosiphon mayottensis Cheek, sp. nov.:
A, habit, whole plant with underground parts exposed; B, inflorescence viewed from above, note navicular bracts; C, flower at anthesis viewed from above, note filamentous style arms; D, flower viewed from side, note the translucent tepals.

 Photos: A, Guillaume Viscardi; B-D, Étienne Vennetier.

 

Martin CHEEK and Sébastien TRACLET. 2020. Gymnosiphon mayottensis Cheek, sp. nov. (Burmanniaceae) A New Species from Mayotte, Comoro Islands. ADANSONIA. 42(8); 179-188. 

  sciencepress.MNHN.fr/en/periodiques/adansonia/42/8

Researchgate.net/publication/341709853_Gymnosiphon_mayottensis_a_new_species_from_Mayotte_Comoro_Islands

 twitter.com/Publi_MNHN/status/1272545402865233921

[Botany • 2022] Vepris teva (Rutaceae) • Chemistry, Taxonomy and Ecology of the potentially Chimpanzee-dispersed Vepris endangered in Coastal Thicket in the Congo Republic

Vepris teva Cheek,  

in Langat, Kami & Cheek​, 2022. 

 DOI: 10.7717/peerj.13926

Abstract 

Continuing a survey of the chemistry of species of the largely continental African genus Vepris, we investigate a species previously referred to as Vepris sp. 1 of Congo. From the leaves of Vepris sp. 1 we report six compounds. The compounds were three furoquinoline alkaloids, kokusaginine (1), maculine (2), and flindersiamine (3), two acridone alkaloids, arborinine (4) and 1-hydroxy-3-methoxy-10-methylacridone (5), and the triterpenoid, ß-amyrin (6). Compounds 1–4 are commonly isolated from other Vepris species, compound 5 has been reported before once, from Malagasy Vepris pilosa, while this is the first report of ß-amyrin from Vepris. This combination of compounds has never before been reported from any species of Vepris. We test the hypothesis that Vepris sp. 1 is new to science and formally describe it as Vepris teva, unique in the genus in that the trifoliolate leaves are subsessile, with the median petiolule far exceeding the petiole in length. Similar fleshy-leathery four-locular syncarpous fruits are otherwise only known in the genus in Vepris glaberrima (formerly the monotypic genus Oriciopsis Engl.), a potential sister species, but requiring further investigation to confirm this phylogenetic position. We briefly characterise the unusual and poorly documented Atlantic coast equatorial ecosystem, where Vepris teva is restricted to evergreen thicket on white sand, unusual in a genus usually confined to evergreen forest. This endemic-rich ecosystem with a unique amphibian as well as plants, extends along the coastline from the mouth of the Congo River to southern Rio Muni, a distance of about 1,000 km, traversing five countries. We map and illustrate Vepris teva and assess its extinction risk as Endangered (EN B1ab(iii)+B2ab(iii)) using the IUCN, 2012 standard. Only three locations are known, and threats include port and oil refinery construction and associated activities, with only one protected location, the Jane Goodall Institute’s Tchimpounga Reserve. Initial evidence indicates that the seeds of Vepris teva are dispersed by chimpanzees, previously unreported in the genus.

Vepris teva Cheek sp. nov.
Shrub with mature (yellow) and immature (green) fruits. Note the sessile leaves.

From Mpandzou et al., 1198 (IEC, K). 

Photo by M. Cheek.

Vepris teva Cheek sp. nov.
 (A) Habit, fruiting stem; (B) detail of leaflet blade showing oil gland dots and nervation, lower surface of blade in foreground; (C) detail of male inflorescence; (D) male flower, side view; (E) as (D), two petals removed to show stamens; (F) pistil of male flower, four-lobed, viewed from above; (G) male flower, two petals and three stamens removed to show pistil; (H) mature fruit, side view (seed on right); (I) fruit, plan view; (J) fruit, transverse section, showing four locules, three aborted and one with seed.

(A and H–J) from Mpandzou et al., 1198, (B and G) from Kami, T. et al 1356; (C–F) from Kami, T. et al., 1227. 

Drawn by Juliet Williamson, CC-BY-NC-ND.

Vepris teva Cheek sp. nov.

Diagnosis: differs from all known trifoliolate species of Vepris in the median petiolule far exceeding the petiole in length (usually by a factor of 2–4 times) on reproductive stems, especially near the stem apex (vs petiole exceeding petiolule in length in all other species). Most similar to Vepris glaberrima (Engl.) J.B.Hall ex D.J. Harris in the soft, leathery-fleshy, four-loculed, and slightly lobed, subverrucate syncarpous fruit, differing in the inflorescences exceeding the petiole in length (vs shorter than the petioles), the secondary nerves (10–)11–16(–18) on each side of the midrib (vs 20–30), the leaflet apices shortly rounded-acuminate (vs long, acutely acuminate) and other characters shown in Table 1 above.

Etymology. Named for Teva Kami, lead collector of the type specimen, who played a key role in the discovery of this species and further research upon it concerning interactions with chimpanzees (see below).

 

Moses K. Langat, Teva Kami and Martin Cheek​. 2022. Chemistry, Taxonomy and Ecology of the potentially Chimpanzee-dispersed Vepris teva sp.nov. (Rutaceae) endangered in Coastal Thicket in the Congo Republic.  PeerJ. 10:e13926. DOI: 10.7717/peerj.13926

 

[Botany • 2022] Uvariopsis dicaprio (Annonaceae) • A New Tree Species with Notes on Its Pollination Biology, and the Critically Endangered narrowly endemic Plant Species of the Ebo Forest, Cameroon

Uvariopsis dicaprio Cheek & Gosline,
 

in Gosline, Cheek​​, Onana, ... et Dagallier, 2022.

DOI: 10.7717/peerj.12614

Abstract 

Background: 

The Ebo Forest area is a highly threatened centre of diversity in the Littoral Region of Cameroon, globally important for conservation with many threatened species including 68 threatened species of plant, yet not formally protected. The tropical African evergreen forest tree genus Uvariopsis Engl. & Diels (Annonaceae) is characterised by unisexual, usually cauliflorous flowers with a uniseriate corolla of four petals, and two sepals. Cameroon is the centre of diversity of the genus with 14 of the 19 known species.

Methods: 

The herbarium collection MacKinnon 51 from Ebo is hypothesized to represent a new species to science of Uvariopsis. This hypothesis is tested by the study of herbarium specimens from a number of herbaria known to hold important collections from Cameroon and surrounding countries.

Results: 

We test the hypothesis that MacKinnon 51 represents a new species to science, using the most recent dichotomous identification key, and comparing it morphologically with reference material of all known species of the genus. We make a detailed comparative morphological study focussing on three other Cameroonian species, Uvariopsis solheidii, U. korupensis and the sympatric U. submontana. In the context of a review of the pollination biology of Uvariopsis, we speculate that in a genus otherwise with species with dull, flesh-coloured (pink, red to brown) flowers pollinated (where known) by diptera, orthoptera and blattodea (flies, crickets and cockroaches), the glossy, pale yellow-green flowers of Uvariopsis dicaprio, with additional traits unique in the genus, may be pollinated by nocturnal moths. Based on MacKinnon 51, we formally name Uvariopsis dicaprio Cheek & Gosline (Annonaceae) as new to science, and we describe, and illustrate, and map it. Restricted so far to a single site in evergreen forest in the Ebo Forest, Littoral Region, Cameroon, Uvariopsis dicaprio is provisionally assessed as Critically Endangered using the IUCN, 2012 standard because the forest habitat of this species remains unprotected, and there exist imminent threats of logging and conversion to plantations.

Discussion: 

We show that the highest density of species of the genus (12), and of narrow endemics (5), is found in the Cross-Sanaga Interval of SE Nigeria and Western Cameroon. A revised key to the 14 Cameroonian species of Uvariopsis is presented. We review the other seven narrowly endemic and threatened species unique to the Ebo forest of Cameroon and discuss the phytogeographic affinities of the area.

Conclusions: 

Uvariopsis dicaprio adds to the growing list of species threatened with extinction at Ebo Forest due to current anthropogenic pressures.

Uvariopsis dicaprio Cheek & Gosline. 
(A) habit, cauliflorous inflorescences on trunk; (B) leafy branch, one season’s growth; (C) inflorescence, showing pedicel articulations, bracts and bracteoles; (D) flower, with one petal removed to show the staminal dome; (E) detail of sparse hairs on abaxial petal surface; (F) stamen, different views; (G) junction of base of leaf with stem, showing dome-like axillary bud.

 All drawn from MacKinnon 51 (K) by Meg Griffiths. 

Uvariopsis dicaprio Cheek & Gosline.
Cauliflorous inflorescences on trunk.

Photo Lorna MacKinnon.

Uvariopsis dicaprio Cheek & Gosline sp. nov.

Syn. Uvariopsis ebo nom. nud. (Gosline et al., 2021: 5).

Diagnosis. Similar to Uvariopsis solheidii (De Wild.) Robyns & Ghesq., differing in the stem, petioles and abaxial midrib glabrous (versus tomentose); number of secondary nerves on each side of the midrib 5–8 (versus 8–13); petals yellow-green, (14–) 16 × (5.5–) 9 mm (versus wine brown, 7–10 × 2.5–5 mm).

HABITAT. Uvariopsis dicaprio is so far only known from lower submontane forest (850 m elev.). below the elevation for the upper montane forest indicator species Podocarpus latifolius (Thunb.) R.Br. ex Mirb. The geology is ancient, highly weathered basement complex, with some ferralitic areas in foothill areas which are inland, c. 100 km from the coast. Altitude varies from c. 200 m to 1,200 m elevation. The wet season (successive months with cumulative rainfall >100 mm) falls between March and November and is colder than the dry season. Average annual rainfall at Bekob measured 2010–2016 is 2,336 mm (E. Abwe, 2018 Ebo Forest Research Programme, Cameroon, personal communication, Abwe & Morgan, 2008; Cheek et al., 2018a).

ETYMOLOGY. This threatened and spectacular tree is named for the American actor and conservationist Leonardo DiCaprio, who, through several months in 2020, lobbied extensively on social media (e.g. instagram.com/p/B_0LSAhFRue; twitter.com/LeoDiCaprio/status/1257729388314943490 both accessed 12 April 2021) to draw attention to threats for the numerous rare Ebo species from the logging concession that had been announced at Ebo earlier that year. The concession was cancelled in August 2020, surely partly due to his efforts.

Conclusions: 

Such discoveries as this new species underline the urgency for making further such discoveries while it is still possible since in all but one of the cases given above, the species have very narrow geographic ranges and/or very few individuals, and face threats to their natural habitat, putting these species at high risk of extinction.

About 2,000 new species of vascular plant have been discovered each year for the last decade or more. Until species are known to science, they cannot be assessed for their conservation status and the possibility of protecting them is reduced (Cheek et al., 2020). Documented extinctions of plant species are increasing, e.g. Oxygyne triandra Schltr. and Afrothismia pachyantha Schltr. of South West Region, Cameroon are now known to be globally extinct (Cheek & Williams, 1999; Cheek et al., 2018c; Cheek, Etuge & Williams, 2019). In some cases, species appear to be extinct even before they are known to science, such as Vepris bali Cheek, also from the Cross-Sanaga interval in Cameroon (Cheek, Gosline & Onana, 2018) and elsewhere, Nepenthes maximoides Cheek (King & Cheek, 2020). Most of the 815 Cameroonian species in the Red Data Book for the plants of Cameroon are threatened with extinction due to habitat clearance or degradation, especially of forest for small-holder and plantation agriculture following logging (Onana & Cheek, 2011). Efforts are now being made to delimit the highest priority areas in Cameroon for plant conservation as Tropical Important Plant Areas (TIPAs) using the revised IPA criteria set out in Darbyshire et al. (2017). This is intended to help avoid the global extinction of additional endemic species such as Uvariopsis dicaprio which will be included in the proposed Ebo Forest IPA.

With only one locality known, Uvariopsis dicaprio represents another narrowly endemic Cameroonian species threatened with extinction due to deforestation for oil palm plantations, small-scale agriculture, mining and logging, widespread threats posing extinction risks to plant species in Cameroon (Onana & Cheek, 2011; Cheek et al., 2018a).

George Gosline, Martin Cheek​​, Jean Michel Onana, Eric Ngansop Tchatchouang, Xander M. van der Burgt, Lorna MacKinnon and Léo-Paul M. J. Dagallier. 2022. Uvariopsis dicaprio (Annonaceae) A New Tree Species with Notes on Its Pollination Biology, and the Critically Endangered narrowly endemic Plant Species of the Ebo Forest, Cameroon. PeerJ. 9:e12614. DOI: 10.7717/peerj.12614

[Botany • 2020] Notes on Tricalysia elmar sp. nov. (Rubiaceae, Coffeeae), and Cloud Forest of the Cameroon Highlands

Tricalysia elmar Cheek

in Cheek, Causon, et al., 2020. 

DOI: 10.5091/plecevo.2020.1661 

 twitter.com/PlEcEvo 

 

Abstract

Background and aims – This paper reports a further discovery in the context of a long-term botanical survey in the Cross River-Sanaga interval of west-central Africa, focussing on species discovery and conservation.

Methods – Normal practices of herbarium taxonomy have been applied to study the material collected. The relevant collections are stored in the Herbarium of the Royal Botanic Gardens, Kew, London and at the Institute of Research in Agronomic Development – National Herbarium of Cameroon.

Key results – Species new to science recently discovered from the cloud (submontane) forests of the Cameroon Highlands in Cameroon are reviewed. Most of these species are rare, highly localised, and threatened by habitat destruction. These discoveries increase the justification for improved conservation management of surviving habitat. Tricalysia elmar Cheek (Coffeeae-Rubiaceae) is described as an additional cloud forest species new to science. Its taxonomic position is discussed, and it is compared with similar species of the genus. Restricted so far to four locations, Mt Kupe, Bali Ngemba, Lebialem and Nta Ali, its conservation status is assessed as Endangered (EN B1+2ab(iii)) according to the 2012 criteria of IUCN.

Keywords: accrescent floral disc, conservation, Cross-Sanaga Interval, submontane forest, Tropical Important Plant Areas

Tricalysia elmar Cheek.
 A. Habit. B. Domatia on leaf abaxial surface. C. Stipules. D. Inflorescence with calyculi, foliar and stipular lobes, flower bud, open flower and flower after corolla drop. E. Corolla lobe tip showing scattered hairs. F. Calyx and 3rd order (distal) calyculus. G. Longitudinal section of flower showing disc, ovary, and base of style. H. Stamens, outer face with anther lobe bases (left) and inner face (right). I. Fruits in situ. J. Fruit apex showing calyx surrounding accrescent disc.

Scale bars: A = 5 cm; B, H, F, G = 2 mm; C, J = 5 mm; D, I = 1 cm; E = 500 μm. A–H from Cheek7619 (K); I–J from Etuge1735 (K), all drawn by Andrew Brown.

Tricalysia elmar Cheek, sp. nov.

Diagnosis – Similar to Tricalysia ferorum Robbr. of Sect. Probletostemon (K.Schum.) Robbr. in the large, conspicuous, dome-like accrescent disc in the fruit, differing in the entire, united distal calyculus (distal bracts not free) and the glabrous style and anthers (not hairy); differing from all species of Sect. Tricalysia in the dome-like accrescent disc in the fruit.

Etymology – Named (indeclinable word in apposition; art. 23.1 and 23.2 of the code, Turland et al. 2018) for Prof. Elmar Robbrecht (1946–) of the Meise Botanic Garden and Herbarium, Belgium, the noted global specialist in Rubiaceae who monographed and laid the systematic foundations for all future research on the genus Tricalysia.

 

Martin Cheek, Isla Causon, Barthelemy Tchiengue and Eden House. 2020. Notes on Tricalysia elmar sp. nov. (Rubiaceae, Coffeeae), and Cloud Forest of the Cameroon Highlands. Plant Ecology and Evolution. 153(1); 167-176. DOI: 10.5091/plecevo.2020.1661

  twitter.com/PlEcEvo/status/1280049747512963073

  twitter.com/BGM_coll_res/status/1243127852293382144

[Botany • 2020] Hibiscus hareyae (sect. Lilibiscus; Malvaceae) • Threatened in Coastal Thicket at Lindi, Tanzania

Hibiscus hareyae L.A.J.Thomson & Cheek

  

in Thomson & Cheek, 2020. 

 DOI: 10.1007/s12225-020-09911-6

Summary

The spectacular new species with horticultural potential described in this paper, Hibiscus hareyae L.A.J.Thomson & Cheek, was identified during an assessment of online digitised botanical specimens of H. schizopetalus (Dyer) Hook.f. as part of a review of species in Hibiscus sect. Lilibiscus Hochr. A short updated description and delimitation of the horticulturally important sect. Lilibiscus is presented. Flowering and fruiting specimens of Hibiscus hareyae are readily distinguished from H. schizopetalus by their short (0.4 – 2 (– 4.5) cm long, non-articulated peduncle-pedicels vs (6 –) 8 – 11 (– 14) cm long, articulated peduncle-pedicels, and larger, broader epicalyx bracts (1.5 – 4 × 1 – 1.2 mm vs 0.6 – 1.5 × 0.1 – 0.3 (– 0.5) mm), the epicalyx forming a shallow cup 0.5 – 1 × 2 – 3 mm vs bracts appearing free. The absence of an articulation of the peduncle-pedicel of H. hareyae is unique within sect. Lilibiscus. The species is also well-marked from H. schizopetalus by other morphological differences in corolla and foliage, and in ecology and geography. Hibiscus hareyae has a restricted natural distribution as an element in deciduous coastal thicket, usually on coral rag formations, sometimes in or near mangrove, in Lindi Province, southern Tanzania. It ranges from the Indian Ocean coast to as much as 20 km inland, from about 8.5oS to 10oS (c. 140 × 20 km) and is assessed as Vulnerable (VU B2ab(iii)). Hibiscus hareyae has high ornamental potential but is unknown in cultivation.

Key Words: Africa, conservation, coral rag, Hibiscus schizopetalus, horticulture

Hibiscus hareyae L.A.J.Thomson & Cheek.
A leaves and inflorescence from above showing epicalyces; B flower from below showing white inner petal markings. From Suleiman et al. 5526 (K).

photos: A. Iain Darbyshire, B. Toral Shah. 

Hibiscus hareyae L.A.J.Thomson & Cheek.
A habit, leafy shoot; B full-sized leaf, abaxial surface; C flowering shoot; D petal; E anther; F anther, inner face; G anther, dorsal face showing filament insertion; H pedicel, epicalyx and calyx; J pedicel detail-indumentum; K calyx margin – indumentum; L epicalyx lobe — indumentum.

From Milne-Redhead & Taylor 7481.

Drawn by Andrew Brown.  

Hibiscus hareyae L.A.J.Thomson & Cheek sp. nov. 

Type: Tanzania, Lindi Province, “Collected July 1877. Lindi, E. Africa, Lat. 9 40’ South this extends its habitats a little further South than before”, Kirk s.n. (holotype K00240493!) (Fig. 1).

RECOGNITION. Within Hibiscus, H. hareyae and H. schizopetalus are the only two species with laciniate petals. Hibiscus hareyae is readily distinguished from H. schizopetalus by its much shorter and non-articulated peduncle-pedicels (0.4 – 2 cm long vs 8 – 14 cm long and articulated); longer and broader epicalyx bracts, (1.5 – 4 × 1 – 1.2 mm vs 0.6 – 1.5 × 0.1 – 0.3 (0.5) mm, the epicalyx forming a shallow cup 0.5 – 1 × 2 – 3 mm, vs bracts appearing free (for additional diagnostic characters see Table 1).

ETYMOLOGY. The specific epithet honours Dr Hareya Fassil (12 Jan. 1968 – present) in recognition of her work on conservation of plant genetic resources and the roles of traditional plant-based medicines in Africa.

VERNACULAR NAMES. Mgongonyoka (Swahili) and Kinyoka (Yau) (both Litchfield 5457); 

Lindi hibiscus (English).

 

Lex A. J. Thomson and Martin Cheek. 2020.  Discovered Online: Hibiscus hareyae sp. nov. of sect. Lilibiscus (Malvaceae), Threatened in Coastal Thicket at Lindi, Tanzania. Kew Bulletin. 75: 51. DOI: 10.1007/s12225-020-09911-6

[Botany • 2020] Nepenthes maximoides (Nepenthaceae) • A New, Critically Endangered (possibly Extinct) Species in Sect. Alatae from Luzon, Philippines showing Striking Pitcher Convergence with N. maxima (Sect. Regiae) of Indonesia

Nepenthes maximoides Cheek,

in King & Cheek​, 2020. 

DOI: 10.7717/peerj.9899

Abstract 

Nepenthes maximoides sp. nov. (Sect. Alatae) is described and assessed as Critically Endangered (Possibly Extinct) from Luzon, Philippines and appears unrecorded in 110 years. The spectacular, large, narrowly funnel-shaped upper pitchers, lids with recurved basal and filiform apical appendages, unlike any other species in the Philippines, closely resemble those of N. maxima (Sect. Regiae) of Sulawesi–New Guinea, likely due to convergent evolution. Following recent phylogenomic analysis, sect. Alatae is divided into two, Sect. Alatae sensu stricto of Luzon to Sibuyan (including N. maximoides), and Sect. Micramphorae, expanded and recircumscribed to encompass those species of the southern Visayas, and Mindanao. A key is provided to the six species now recognised in the newly narrowly recircumscribed Sect. Alatae. The number of Nepenthes species recorded from Luzon has increased from two in 2001, to eight in 2020, all but one of which are endemic to that island, and four of which appear to be point endemics.

Figure 1: Nepenthes maximoides Cheek.
Photo of the type specimen Curran s.n. (Univ. Pennsylvania sheet 70707), PH. Note that material is mounted pitchers facing downward.

Photo by Martin Cheek.

Figure 2: Nepenthes maximoides Cheek. 
(A) Habit, showing climbing stem with two upper pitchers; (B) exterior of upper pitcher showing junction of peristome, lid and spur.; (C) lower surface of the lid of the upper pitcher showing basal and apical appendages; dotted line indicates outer limit of nectar glands which are absent from the lid margin; (D) detail outermost lid nectar glands on underside lid; (E) detail lid nectar glands near/on basal appendage (same scale as D); (F) detail basal appendage with gland distribution; (G) detail apical appendage; (H) minute branched and stellate hairs of lid margin; (I) peristome near lid, viewed from exterior; (J) inner edge of peristome near lid; (K) peristome of upper pitcher, transverse section, outer surface of pitcher to the right; (L) midrib of leaf blade, adaxial surface, showing simple hairs; (M) sessile depressed-globose glands on abaxial leaf-blade surface; (N) margin of young leaf-blade showing hairs (all: Curran s.n. Univ. Pennsylvania sheet 70707). Drawn by Andrew Brown.

Nepenthes maximoides Cheek, sp. nov. 

Differing from Nepenthes graciliflora Elmer in the upper pitchers narrowly infundibulate, widest in the distal half at the peristome (not ovoid-cylindric, widest in the proximal half), the peristome broad, flattened, and lobed on the outer edge (not narrowly cylindrical and entire on the outer edge), the lid with an asymmetrically hooked basal appendage and a filiform apical appendage (not symmetrical non-hooked, and absent, respectively). 

Type: Curran s.n., Herb. Univ. Pennsylvania sheet number 70707, Academy of Natural Sciences Philadelphia sheet number 01113309 (holotype PH; isotype PNH destroyed, not seen), Philippines, Luzon, ‘Tayabas Province’ (deduced to be Mt Banahaw, Quezon Prov.) st. December 1911.

Etymology. Meaning that the species looks like Nepenthes maxima Nees (since it looks so similar to this species that it was confused with it).

Conclusions: 

The dramatic rise in the numbers of Philippine species of Nepenthes in the 21st century (see “Introduction”) is mirrored in other plant groups such as Rafflesia R.Br. (Rafflesiaceae). Before 2002 only two species of Rafflesia were thought to be known from the Philippines (subsequently two additional, long-overlooked species came to light), and, as in Nepenthes, the genus was thought to be most diverse in Borneo and Sumatra. Intensive fieldwork in remaining patches of forest in the Philippines, however, has raised species numbers steadily from two species in 2002 to 13 species in 2019, and Philippines now is the most species-diverse country for Rafflesia globally (Barcelona, Pelser & Cajano, 2007; Barcelona et al., 2009; Pelser et al., 2013, 2019).

The number of flowering plant species known to science is disputed (Nic Lughadha, Bachman & Govaerts, 2017), but a reasonable estimate is 369,000 (Nic Lughadha et al., 2016), while the number of species described as new to science has been at about 2,000 per annum for at least 10 years (Cheek et al., 2020). The conservation status of 21–26% of plant species has been established using evidence-based assessments, and 30–44% of these rate the species assessed as threatened, while only c. 5% of plant species have been assessed using the IUCN (2012) standard (Bachman, Nic Lughadha & Rivers, 2018). Newly discovered species such as Nepenthes maximoides, are likely to be threatened, since widespread species tend to have been already discovered and it is the more localised, rarer species that remain to be found although there are exceptions such as Gouania longipedunculata Cahen, Stenn & Utteridge (2020) which is widespread. This makes it urgent to discover and protect such localised species before they become extinct due to habitat clearance as was the case with Nepenthes extincta Cheek & Jebb (2013a). However, it may be too late for Nepenthes maximoides, which may be extinct already, although efforts to rediscover it should be made in case not.

Charles King and Martin Cheek​. 2020. Nepenthes maximoides (Nepenthaceae) A New, Critically Endangered (possibly Extinct) Species in Sect. Alatae from Luzon, Philippines showing Striking Pitcher Convergence with N. maxima (Sect. Regiae) of Indonesia. PeerJ. 8:e9899. DOI: 10.7717/peerj.9899

[Botany • 2018] Vepris bali (Rutaceae) • A New Critically Endangered (possibly Extinct) Cloud Forest Tree Species from Bali Ngemba, Cameroon

Vepris bali Cheek

in Cheek, Gosline & Onana, 2018

  DOI:  10.3372/wi.48.48207 

Abstract 

Vepris bali is the first known species of Vepris in WC Africa with opposite, trifoliolate leaves and is further unusual for its long petiolules. Known only from Bali Ngemba Forest Reserve, a remnant of submontane forest under great pressure of degradation in the Bamenda Highlands of Cameroon, it may already be extinct due to tree cutting and agricultural incursions. Here, V. bali is compared with other endemic cloud forest Vepris of the Cameroon Highlands and is described, illustrated, mapped and assessed as Critically Endangered (Possibly Extinct) using IUCN 2012 criteria.

Fig. 1. Vepris bali. A: habit, flowering stem with male inflorescence; B: stem detail showing indumentum and lenticels; C: abaxial leaf surface showing oil glands; D: portion of partial-inflorescence showing bracts; E: male flower, side view; F: male flower, 2 sepals and petals removed and staminal filaments truncated; G: cross-section of rudimentary pistil.

 Drawn from the holotype, Ujor FHI 30422 (K), by Hazel Wilks.

Vepris bali Cheek, sp. nov. 

– Toddaliopsis ebolowensis sensu Letouzey (1963: 108), non Engl. (1917: 305).

– Vepris cf. heterophylla sensu Mziray (1992: 73), non (Engl.) Letouzey (1966: 246).

– “Vepris sp. B” Cheek in Harvey & al. (2004: 55 [fig. 7], 124); Onana & Cheek (2011: 309).

Diagnosis — Differing from Vepris ebolowensis (Engl.) Onana in being a submontane tree, with a trunk c. 28 cm in diam, at 1.5 m from ground, leaves opposite, and median petiolules 9–14 mm long (whereas V. ebolowensis is a shrub of lowland forest, with leaves alternate, and median petiolules c. 0 mm long).

Holotype: Cameroon, Northwest Region, “Bamenda District, Bali-Ngemba Forest Reserve, in high forest on ... at the height of  1700 m. alt. with Uapaca sp., Garcinia sp., and Aningeria”, male fl., Mar 1951, Ujor FHI 30422 (K; isotype: FHI n.v.).

....

Etymology — The specific epithet is a noun in apposition, from the town and people of Bali in the Bamenda Highlands of the Northwest Region of Cameroon, near which, in the Bali Ngemba Forest Reserve, the only known locality for this tree is found.

Martin Cheek, George Gosline and Jean-Michel Onana. 2018. Vepris bali (Rutaceae), A New Critically Endangered (possibly Extinct) Cloud Forest Tree Species from Bali Ngemba, Cameroon. Willdenowia. 48(2); 285-292. DOI:  10.3372/wi.48.48207

New Tree Species Discovered — and Declared Extinct   therevelator.org/tree-discovered-extinct/

[Botany • 2018] Talbotiella cheekii (Leguminosae: Detarioideae) • A New Tree Species from Guinea

Talbotiella cheekii Burgt

in van der Burgt, Molmou, Diallo, et al., 2018.

  DOI: 10.1007/s12225-018-9755-4 

Summary

Talbotiella cheekii Burgt, a new tree species from Guinea, is described and illustrated. It is a tree to 24 m high, with a stem diameter to 83 cm, and occurs in forest dominated by tree species of the Leguminosae subfamily Detarioideae, on rocky stream banks and rocky hill slopes, at an altitude of 100 – 600 m. It is estimated that 1600 – 2400 mature trees have been seen, in about twelve forest patches; more trees may be present in places not yet visited. One of the localities of the new species is situated at only 46 km northeast of the centre of the capital Conakry and 6 km northeast of the town centre of Coyah, part of the Conakry urban agglomeration. Its distribution is 1400 km further west from the previous westernmost distribution of the genus. The current extent of occurrence is 166 km2. Talbotiella cheekii is here assessed as Endangered (EN) following IUCN Red List categories.

Key Words: Conservation, Endangered species, West Africa 

 Talbotiella cheekii Burgt.
 A branch with inflorescences; B leaf upper surface; C infructescence with three fruits; D leaflet lower surface showing two glands; E stipule; F auriculate stipule; G flower.

 A, E, G from Burgt 2087; B, D, F from Burgt 2065; C from Molmou 988. drawn by Xander van der Burgt.

 Talbotiella cheekii Burgt.
A two flowers; B twig with inflorescences; C infructescence with two fruits; D leaves.

 A – B from Burgt 2087; C from Molmou 988; D from Burgt 2065. 

PHOTOS: A, B, D Xander van der Burgt; C Martin Cheek.

Talbotiella cheekii Burgt sp. nov.

Recognition: Talbotiella cheekii is morphologically similar to T. batesii Baker f. The pedicels of T. cheekii are pink to red, 9 – 24 mm long; the bracteoles are 8 – 15 × 0.7 – 1.5 mm (the pedicels of T. batesii are white, 4 – 10.5 mm long; the bracteoles are 6 – 8.5 × 1.1 – 2.5 mm). The ovary of T. cheekii is reddish green to dark red, and glabrous with only the edges densely hairy (the ovary of T. batesii is pale pink, and densely hairy). The pod of T. cheekii is glabrous, the sutures sparsely hairy (the pod of T. batesii has the surfaces and suture moderately puberulous). The leaflet apex of T. cheekii is rounded to slightly emarginate (the leaflet apex of T. batesii is acute).

DISTRIBUTION: Guinea (Map 1). Talbotiella cheekii occurs on the sandstone plateau in the northern part of Coyah Préfecture. Its distribution just extends into Dubreka and Kindia Préfectures.

Etymology: Talbotiella cheekii is named after Dr Martin Cheek, Head of the Africa & Madagascar Team in the Identification and Naming Department of the Royal Botanic Gardens, Kew. The new species was discovered thanks to his long-standing commitment to the study of African plants. He has been studying the flora of Guinea on field expeditions since 2005, supported the restoration of the National Herbarium of Guinea, and described a new genus and four new species from the country (Cheek & Burgt 2010; Cheek & Haba 2016a, 2016b; Cheek & Williams 2016; Cheek et al. 2016). He is also involved in the designation of new protected areas in Guinea as part of Kew’s Tropical Important Plant Areas (TIPAs) Project (Darbyshire et al. 2017) and is supervising a Darwin Initiative-funded project on rare plant species conservation in the country.

Vernacular Name: Linsonyi (from Burgt 2084); Meni (from Molmou 988); Wonkifong wouri khorohoi (from Burgt 2097), translated as the “Tree with hard wood from Wonkifong”. This last name was proposed by the people of Malassi village when the trees were shown to them. All three names are in the Susu language.

Notes: 

Talbotiella cheekii is characterised by the long pedicels, pink to red in colour, the long and narrow bracteoles, the glabrous pod (only the margin sometimes has a few hairs) and the rounded to slightly emarginate leaflet apex. Apart from this, the leaves and leaflets of T. cheekii and T. batesii are more or less similar; both species have 9 – 14 pairs of leaflets per leaf. Of all previously described Talbotiella species, T. cheekii is morphologically most similar to T. batesii. This is remarkable, because T. batesii is the easternmost species of Talbotiella, occurring in southeast Cameroon, northeast Gabon and north Congo (Brazzaville), at 2900 to 3100 km distance from T. cheekii, the westernmost species. A molecular analysis might show, however, that T. cheekii is more closely related to a different species, for example to T. gentii from Ghana, geographically the nearest of the eight existing Talbotiella species.

Two more plant species from the Leguminosae family have been newly discovered in Guinea in recent years: Eriosema triformum Burgt (Burgt et al. 2012), a pyrophytic herb with unifoliolate leaves, from submontane grassland, endemic to the Pic de Fon area in the Simandou Range, and Gilbertiodendron tonkolili Burgt & Estrella (Estrella et al. 2012), a tree from well-drained sandy and/or rocky soils on river banks and forest patches, first discovered in Sierra Leone, and later found to occur also in Guinea (e.g. the specimens Cheek 16172, 16583 and 16614; all in HNG and K).

Xander M. van der Burgt, Denise Molmou, Almamy Diallo, Gbamon Konomou, Pepe M. Haba and Sékou Magassouba. 2018. Talbotiella cheekii (Leguminosae: Detarioideae), A New Tree Species from Guinea. Kew Bulletin.  73:26. DOI: 10.1007/s12225-018-9755-4

[Botany • 2018] Kindia gangan • A New Cliff-dwelling Genus (Pavetteae, Rubiaceae) with Chemically Profiled Colleter Exudate from Mt Gangan, Republic of Guinea

Kindia gangan Cheek

in Cheek, Magassouba, Howes, Doré, Doumbouya, et al​., 2018.

 DOI: 10.7717/peerj.4666 

Photos: Martin Cheek.

 Abstract

A new genus Kindia (Pavetteae, Rubiaceae) is described with a single species, Kindia gangan, based on collections made in 2016 during botanical exploration of Mt Gangan, Kindia, Republic of Guinea in West Africa. The Mt Gangan area is known for its many endemic species including the only native non-neotropical Bromeliaceae Pitcairnia feliciana. Kindia is the fourth endemic vascular plant genus to be described from Guinea. Based on chloroplast sequence data, the genus is part of Clade II of tribe Pavetteae. In this clade, it is sister to Leptactina sensu lato (including Coleactina and Dictyandra). K. gangan is distinguished from Leptactina s.l. by the combination of the following characters: its epilithic habit; several-flowered axillary inflorescences; distinct calyx tube as long as the lobes; a infundibular-campanulate corolla tube with narrow proximal section widening abruptly to the broad distal section; presence of a dense hair band near base of the corolla tube; anthers and style deeply included, reaching about mid-height of the corolla tube; anthers lacking connective appendages and with sub-basal insertion; pollen type 1; pollen presenter (style head) winged and glabrous (smooth and usually hairy in Leptactina); orange colleters producing a vivid red exudate, which encircle the hypanthium, and occur inside the calyx and stipules. Kindia is a subshrub that appears restricted to bare, vertical rock faces of sandstone. Fruit dispersal and pollination by bats is postulated. Here, it is assessed as Endangered EN D1 using the 2012 IUCN standard. High resolution LC-MS/MS analysis revealed over 40 triterpenoid compounds in the colleter exudate, including those assigned to the cycloartane class. Triterpenoids are of interest for their diverse chemical structures, varied biological activities, and potential therapeutic value.

Taxonomic Treatment

Kindia Cheek, gen nov.

Type: Kindia gangan Cheek

Diagnosis: differs from Leptactina s.l. in a corolla tube with a slender proximal part and an abruptly much wider, longer distal part (not more or less cylindrical, or gradually widening); a glabrous, winged pollen-presenter (not hairy, non-winged); an epilithic habit (not terrestrial, growing in soil); a conspicuous opaque red colleter exudate (not translucent and colourless or slightly yellow); and type 1 pollen (not type 2) (De Block & Robbrecht, 1998).

Figure 1: Photographs showing the cliff-dwelling habitat and the habit of Kindia gangan at Mt Gangan, Kindia, Guinea. (A) plants scattered on high sandstone cliff (Cheek 18345); (B) plant habit on cliff face (Cheek 18541A); (C) frontal view of flower (Cheek 18541A); (D) side view of inflorescence showing cupular bract (Cheek 18541A); (E) opened fruit showing ripe seeds (Cheek 18345). Photos taken by Martin Cheek.

Figure 1: Photographs showing the cliff-dwelling habitat and the habit of Kindia gangan at Mt Gangan, Kindia, Guinea.
(A) plants scattered on high sandstone cliff (Cheek 18345); (B) plant habit on cliff face (Cheek 18541A).

Photos taken by Martin Cheek.

Figure 1: Photographs showing the cliff-dwelling habitat and the habit of Kindia gangan at Mt Gangan, Kindia, Guinea.
 (C) frontal view of flower (Cheek 18541A); (D) side view of inflorescence showing cupular bract (Cheek 18541A); (E) opened fruit showing ripe seeds (Cheek 18345). Photos taken by Martin Cheek.

Local names and uses: None are known. The local communities in the area when interviewed in November 2017, stated that they had no uses nor names for the plant (D Molmou & T Doré, pers. obs., 2017).

Etymology: The genus is named for the town and prefecture of Kindia, Guinea’s fourth city, and the species is named for Mt Gangan to its north, which holds the only known location for the species. Both names are derived as nouns in apposition.

Distribution République de Guinée, Kindia Prefecture, northeastern boundary of Mt Gangan area, west of Kindia-Telimélé Rd (Fig. 5).

Ecology: 

The area of the Mt Gangan complex in which we found plants of Kindia consists of two parallel ranges of small sandstone table mountains separated by a narrow N–S valley that appears to be a geological fault. Bedding of the sandstone is horizontal. Uneven erosion on some slopes has resulted in the formation of frequent rock ledges, overhangs and caves. In contrast, other flanks of the mountains are sheer cliffs extending 100 m or more high and wide. It is on the cliff areas at 230–540 m a.s.l that K. gangan occurs as the only plant species present, usually as scattered individuals in colonies of (1–3–)7–15 plants, on the bare expanses of rock that are shaded for part of the day due to the orientation of the cliffs or to overhangs or due to a partial screen of trees in front of the rockfaces. Pitcairnia feliciana (Bromeliaceae), in contrast is found in fully exposed sites where there is, due to the rock bedding, a horizontal sill in which to root. These two species can grow within metres of each other if their cliff microhabitats occur in proximity. The rock formations create a variety of other microhabitats, including vertical fissures, caves, shaded, seasonally wet ledges, and are inhabited by sparse small trees, shrubs, subshrubs, perennial and annual herbs, many of which are narrow endemic rock specialists. We speculate that the seed of this species might be bat-dispersed because of the greenish yellow-white colour of the berries (less attractive to birds than fruits which are e.g., red or black) and the position of the plants high on cliff faces, where nothing but winged creatures could reach them, apart from those few plants at the base of the cliffs. However, fruit dispersal is not always effected since we found numerous old dried intact fruits holding live seeds on the plants at the type locality in February 2016. It is possible that the robust, large white flowers are pollinated by a small species of bat since in June and September we saw signs of damage to the inner surface of the corolla inconsistent with visits by small insects. The damage takes the form of brown spots on the inner surface of the corolla tube. Freshly opened flowers do not have these spots, nor do all flowers, only those few which show slight damage. The very broad, short corolla is not consistent with pollination by sphingid moths (which prefer long, slender-tubed flowers), but this cannot be ruled out.

Conclusions: 

Kindia, an endangered subshrub, restricted to bare, vertical rock faces of sandstone is described and placed in Clade II of tribe Pavetteae as sister to Leptactina s.l. based on chloroplast sequence data. The only known species, K. gangan, is distinguished from the species of Leptactina s.l. by a combination of characters: an epilithic habit; several-flowered axillary inflorescences; distinct calyx tube as long as the lobes; a infundibular-campanulate corolla tube with narrow proximal section widening abruptly to the distal section; presence of a dense hair band near base of the corolla tube; anthers and style deeply included, reaching about mid-height of the corolla tube; anthers lacking connective appendages and with sub-basal insertion; pollen type 1; pollen presenter winged and glabrous; orange colleters, which encircle the calyx-hypanthium, occur at base and inside the calyx and stipules and produce vivid red exudate. High resolution LC-MS/MS analysis revealed over 40 triterpenoid compounds in the colleter exudate, including those assigned to the cycloartane class. Triterpenoids are of interest for their diverse chemical structures, varied biological activities, and potential therapeutic value.

Martin Cheek, Sékou Magassouba, Melanie-Jayne R. Howes, Tokpa Doré, Saïdou Doumbouya, Denise Molmou, Aurélie Grall, Charlotte Couch and Isabel Larridon​. 2018. Kindia (Pavetteae, Rubiaceae), A New Cliff-dwelling Genus with Chemically Profiled Colleter Exudate from Mt Gangan, Republic of Guinea.  PeerJ. 6:e4666. DOI: 10.7717/peerj.4666