Deinbollia onanae Cheek, 2021

Cheek, Martin, Onana, Jean Michel & Chapman, Hazel M., 2021, The montane trees of the Cameroon Highlands, West-Central Africa, with Deinbollia onanae sp. nov. (Sapindaceae), a new primate-dispersed, Endangered species, PeerJ 9, pp. 1-25 : 6-12

publication ID	https://doi.org/ 10.7717/peerj.11036
DOI	https://doi.org/10.5281/zenodo.4612622
persistent identifier	https://treatment.plazi.org/id/039ED21A-FFE1-4253-463A-FBEAFB0CFD76
treatment provided by	Donat
scientific name	Deinbollia onanae Cheek
status	sp. nov.

Treatment

Deinbollia onanae Cheek View in CoL sp. nov.

Figs. 1 4 View Figure 1 View Figure 2 View Figure 3 View Figure 4

Similar to but differing from Deinbollia oreophila Cheek in the length of leaves of flowering stems (14)60 70 cm (versus 25 63 cm), number of leaflets per leaf (4)16 23 (versus (4)6 8(10)), width of leaflets (2.1)2.5 4 cm (versus (3)5.5 9(10.2) cm, number of secondary nerves on each side of midrib (15)17 18, (versus (7)9 14(17); stems with lenticels brown, concolorous and inconspicuous, (versus discolorous, bright white and conspicuous), ovary bilocular (versus trilocular)

. Typus: Cameroon, Mt Oku and the Ijim Ridge, Aboh to Tum , 2400 m alt., fl. 22 Nov. 1996, Etuge 3600 (holotype K000337729 ! Fig. 2 View Figure 2 , isotypes MO!, WAG0336084 View Materials !, WAG0336083 View Materials !, YA0057050 !) ;

Deinbollia cf. pinnata Schum. & Thonn., sensu Cheek View in CoL , in Cheek, Onana & Pollard (2000:162).

Deinbollia sp. 2 sensu Cheek in Harvey et al. (2004: 125); Cheek & Etuge in Cheek et al. (2004: 399); Cheek in Cheek, Harvey & Onana (2010: 143, fig 23).

Deinbollia sp. Chapman & Chapman ( Chapman & Chapman, 2001: c41)

Monoecious tree or treelet (4)5 15 m tall, trunk 14.5 40 cm diameter at 1.3 m from the ground, lacking exudate or scent when wounded, sparingly branched, nearly glabrous, apart from the inflorescence. Stems of flowering branches terete (0.8)1 1.5 cm diameter, solid (not hollow), second internode below apical inflorescence 2 2.5 cm long, outer epidermis pale grey-brown, contrasting with the darker brown bases of the adjoining petiolar pulvini, lenticels dense, raised, elliptic, 0.6 1.1 mm long, concolorous, inconspicuous, glabrescent, hairs sparse to dense, dark brown, cylindric 0.1 0.5 mm long.

Leaves alternate, pinnately compound, (14)60 70 cm long; leaflets (4)16 23 per leaf on flowering stems, leaflets 10 14 per leaf on leaves of juvenile trees. Petiole (4)9.5 20.8 cm long, terete, c. four mm diameter at midpoint, drying pale yellow; basal pulvini dark brown; rhachis (4.5)32 44 cm long, (2)8 11-jugate on flowering stems, 5 7-jugate on non-flowering stems of juvenile trees, the upper surface of the distal half flattened with two thin lateral wings and with a central dark hairy rounded central ridge, the rest of the rhachis glabrescent with sparse inconspicuous hairs (de Wilde 4555), or with sparse dark brown appressed hairs (Cable 3386). Leaflets mostly oblong (6.6)14 19.5 × (2.1)2.5 4 cm, (but leaflets of sterile branches to 6.5 cm wide), acumen c. 1 cm long, base broadly acute, slightly asymmetric, (basalmost leaflets lanceolate and about half the length of the other leaflets) lateral nerves and midrib yellow, raised above and below, convex, (15)17 18 on each side of the midrib, nearly brochidodromous, the lateral nerve apices forming a weak irregular submarginal nerve, stronger branches uniting with the secondary nerve above, intersecondary nerves strong, parallel to the secondaries, tertiary and quaternary nerves reticulate raised yellow and conspicuous, on both surfaces, contrasting with the pale grey-green areolae (except in Cable 3386(K) where they are concolorous and so inconspicuous above, possibly an artefact of poor drying); upper surface glabrous, lower surface with inconspicuous, minute, cylindrical, subappressed glossy dark-brown hairs c. 0.25 mm long, distributed very sparsely along the midrib and secondary nerves, absent from mature leaves of non-flowering specimens (e.g., Cheek 8709) but then the same hair type present on axillary buds and young leaves; petiolules yellow, 2 5 mm long, glabrous.

Inflorescence a 80 120-flowered, loose, terminal panicle 25 × 10 cm; auxiliary inflorescences sometimes present in the axils of the distal 1 4 leaves (Cheek 13625); peduncle of terminal inflorescences 0 2 cm long; rhachis internodes (1)2 3 cm long, shortest in the distal portion; first order bracts caducous; indumentum brown hairy; primary branches 10 20 per inflorescence, 2 8 cm long, each bearing (1)2 5 partialinflorescences; partial-peduncles 0 5 mm long, apex with a cluster of 3 5 bracteoles; bracteoles subulate to narrowly lanceolate, 2 3 mm long, apex narrowly acute, partialinflorescences (1)3-flowered in glomerules, pedicels erect, terete, 3 4 × 1.5 mm (female), 4 5 × 1 mm (male), sparsely puberulent, hairs 0.1 0.5 mm long.

Flowers white, scent not recorded, flower buds c. four mm diam., open flowers c. 6 × 7 mm. Calyx with sepals 5(6), orbicular to broadly ovate, concave, green colour, 4 5 × 3.5 4.5 mm apex obtuse. Corolla apex slightly exserted from calyx, petals rhombic or spatulate. Male flowers ( Fig. 1C View Figure 1 ). Petals 5(6), white, rhombic c. 5 × 3 mm, apex obtuse-acute, base cuneate, margins densely ciliate, hairs 0.3 mm long, outer surface glabrous, inner surface glabrous in distal half, proximal half compressed funneliform with ventral appendage adnate at margins, retuse (notched) for 0.5 mm at midline, adaxial surface moderately densely hairy, hairs c. 0.3 mm long. Extra-staminal disc torus-like, glabrous, irregular, outer wall convex, lacking constrictions or teeth with c. 15 poorly defined lobes, 2.5 3 mm wide, c. 0.8 mm high. Stamens c. 15, erect, slightly exserted by 1 2 mm at anthesis, c. 5 6.5 mm long; filament 4 5 mm long, straight, densely puberulent the entire length ( Fig. 1D View Figure 1 ); anthers yellow, ovate-ellipsoid, 1 1.3 mm long. Ovary (vestigial, Fig. 1E View Figure 1 ) bilobed, c. 1 × 1.5 mm densely appressed hairy, hairs c. 0.5 mm; style 0.7 mm long, glabrous.

Female flowers ( Fig. 1G View Figure 1 ), with sepals and petals as the male flowers, but petals c. 6 × 2.6 2.9 mm, usually detaching with a stamen attached, probably due to interlocking hairs (see Fig. 1J View Figure 1 ), proximal two-thirds claw-like, c. 0.7 mm wide, margin sparsely and irregularly ciliate; ventral appendage with apex deeply bilobed, lobes c. 1 mm × 1 mm; disc as in male flower. Stamens c. 10 (see Fig. 1I View Figure 1 ), included at anthesis, filament c. 2.5 mm long, proximal half to quarter glabrous, distal part densely hairy; anther as male flowers but indehiscent; ovary bilobed (see Fig. 1H View Figure 1 ), 3.2 × 5 mm, indumentum as male flower, style c. 5 mm long, apical 1 mm, curved, surface papillate-minutely puberulent, apex subcapitate. Infructescence, of same dimensions as inflorescence, erect. Fruit colour recorded as nearly black when ripe, tasting sweet-sour (Elisha Barde, see uses below), and not coloured yellow when ripe (as in other species of the genus), mericarps 1 or 2, transversely ellipsoid, c.1.8 × 2.1 × 1.2 cm (hydrated), the surface leathery, shallowly and finely muricated, glabrous, mesocarp spongy and juicy, 1-seeded. Seed ellipsoid, c. 1.8 × 1.1 × 0.8 cm, testa thin, parchment like, endosperm absent, cotyledons fleshy.

Phenology: flowering in November-December; fruiting in February and April, immature fruit recorded in December and June.

Local name and uses: none are reported in Cameroon but in Ngel Nyaki, Nigeria, Elisha Emmanuel Barde of the Nigeria Montane Forest Project (pers. comm. to M. Cheek Dec.

2020), states that Nyeberehi (Fulfude) is the general name for all Deinbollia species while Jellahi (Fulfude) is a specific name for Deinbollia onanae in Ngel Nyaki where Fulfude speakers (Fulanis) use the bark of this species as medicine for themselves, to treat stomach aches as well as an anti-helminthic. It is not used for treating cattle. The fruits are reported to taste sour-sweet by Mr Barde. The species is also known as Pabba (Ndolla language).

Etymology: The specific epithet of Deinbollia onanae means ‘of Onana’ commemorating Dr Jean-Michel Onana, currently Senior Lecturer in Botany at the University of Yaoundé I, Cameroon, champion of plant conservation in Cameroon, specialist in Sapindales ( Burseraceae , author of Flore du Cameroun Burseraceae ( Onana, 2017) , co-chair of the IUCN Central African Red List Authority for Plants, former Head of the National Herbarium of Cameroon (2005 2016), co-author of the Red Data Book of the Plants of Cameroon ( Onana & Cheek, 2011) and the Taxonomic Checklist of the Vascular Plants of Cameroon ( Onana, 2011). He led field teams of YA staff working with those of K that resulted in the collection of several of the specimens of this species and personally collected this species in the field (Onana 1600, K, YA).

Distribution & ecology: known only from the Cameroon Highlands of Cameroon (one location in the adjoining Mambilla Plateau, Nigeria) Fig. 3 View Figure 3 . Upper submontane & montane evergreen forest, sometimes in gallery forest; (1200) 2,050 2,200 m alt.

Additional specimens: CAMEROON. South West Region, Mt Kupe, near main summit, immature fr., 26 June 1996, Cable 3386 ( K000197863 !, YA!) ; North West Region.

Bali Ngemba Forest Reserve, fr. April 2002, Onana 1600 ( K!) ; Mt Oku and the Ijim Ridge: above Laikom , st. 21 Nov ..1996, Cheek 8709 ( K000337728 ! YA!) ; Dom, Kinjinjang Rock , st. 25 Sept. 2006, Cheek 13436 ( K000580433 !; YA!) ; ibid. Forest Patch 1, fl. buds, 27 Sept. 2006, Cheek 13625 ( K000580434 !, MO!,US!, YA!) ; ibid., Javelong Forest , st. 29 April 2005, Pollard 1400 ( K000580432 !; YA!) ; Adamaoua Region, c. 120 km E of Ngaoundéré, 15 km NE of Belel, falls in Koudini River, alt. ± 1200 m, fl. 4 Dec. 1964, W.J.J.O. & J.J.F.E. de Wilde, B.E.E. de Wilde-Duyfjes 4555 ( K000593309 !; K000593310 !, WAG1269760 View Materials !, YA) . NIGERIA. Taraba State, Mambilla Plateau, Ngel Nyaki Forest Reserve , near camp, fr. 2 Dec. 2003, H.M. Chapman 481 ( FHI, K!) ; ibid. female fl. 4 Dec. 2002, H.M. Chapman 484 ( FHI, K!) .

Notes: Deinbollia onanae first came to our attention in 2000 when completing the ‘‘Plants of Kilum-Ijim’’ ( Cheek, Onana & Pollard, 2000). Two specimens of Deinbollia matched no other and were named Deinbollia cf. pinnata ( Cheek, Onana & Pollard, 2000) . In subsequent surveys this taxon was more explicitly referred to as a new species: Deinbollia sp. 2 ( Harvey et al., 2004; Cheek et al., 2004; Cheek, Corcoran & Horwath, 2009). However, the earliest known collection was made in 1964 (W.J.J.O. & J.J.F.E. de Wilde, de Wilde-Duyfjes 4555(K)).

This species is remarkable for the very large number of pairs of unusually long and slender leaflets ( Fig. 4 View Figure 4 ), and for the comparatively large size of the individuals which often attain 10 15 m in height ( Fig. 4 View Figure 4 ), among the largest trees known in the genus. However, at Ngel Nyaki trees can begin flowering at only 2.5 m in height (E. Barde pers. comm. to Cheek Jan. 2020)

Conservation: Deinbollia onanae is rare at each of its six known locations so far as is known, although at Ngel Nyaki this is difficult to establish due to potential confusion with Deinbollia oreophila . Despite many thousands of herbarium specimens being collected at Kilum-Ijim, at Mt Kupe and the Bakossi Mts, at Ngel Nyaki and at Bali Ngemba ( Cheek, Onana & Pollard, 2000; Cheek et al., 2004; Harvey et al., 2004) only two specimens of this species at two sites, were made at each of the first three locations and only one at the third location. Surveys at other sites with suitable habitat in the Cameroon Highlands and elsewhere, e.g at Mt Cameroon and at the Lebialem Highlands, failed to find this species ( Cheek et al., 1996; Cable & Cheek, 1998; Harvey, Tchiengue & Cheek, 2010; Cheek, Harvey & Onana, 2011). However, at Dom, where a targetted search for this species was made by the first author, three specimens were made, each representing single, isolated trees Cheek, Harvey & Onana (2010). No more individuals than these were found. At Adamaoua Region, Cameroon it has only been collected once, and only a single tree was then noted (W.J.J.O. & J.J.F.E. de Wilde, B.E.E. de Wilde-Duyfjes 4555(K)). None of these locations is formally protected for nature conservation. Tree cutting for timber and habitat clearance for agriculture has long been known to be a threat at all but the last of these locations (references cited above). The range of the species is large: extent of occurrence was calculated as 50,525 km 2 using GeoCAT. However, severe habitat fragmentation has resulted over many hundreds of years, forest patches being now distant from each other by tens of kilometres, isolated in oceans of cultivation and secondary fire-maintained grassland making the possibility of primate-mediated dispersal from one forest area to another now extremely unlikely. Ecological evidence from Ngel Nyaki is that while Deinbollia regenerates in that forest patch, its primate dispersers do not, or seldom cross to other forest patches ( Dutton & Chapman, 2015, see discussion below). We assess the area of occupancy of Deinbollia onanae as 34 km 2 using the IUCN preferred 4 km 2 cell size. Therefore, we assess this species as Endangered, EN B2ab(iii) using the IUCN (2012) standard. We suggest that this species be included in forest restoration plantings within its natural range to partly reverse its move to extinction. However, the large (c. one cm diam.), thin-walled seeds are probably recalcitrant, so not suitable for conventional seed-banking, and should not be allowed to be dried before sowing since this can be expected to kill them. Experience at Ngel Nyaki ( Matthesius, Chapman & Kelly, 2011) shows that it is possible to raise hundreds of seedlings in nurseries and to establish them in natural forest.