Taxonomic novelties in the genus Campylospermum ( Ochnaceae )

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The new species published here are part of our on-going research efforts on the systematics of Ouratinae in cooperation with the Senckenberg Research Institute at Frankfurt.Rhab dophyllum was revised recently (Sosef 2008), but notably the taxonomy of Campylospermum is still unclear.The first author is preparing her PhD thesis on the taxonomy, phylogeny and biogeography of Ochnaceae, with an emphasis on Campylo spermum.Most of the novelties resulting from her taxonomic work on the continental African representatives are presented here.Molecular phylogenetic work in progress (Bissiengou, unpubl. data) has not yet led to sufficient resolution in the phylogenetic tree and hence does not yet allow resolving the relationships among the four Ouratinae genera.Being unable to anticipate future phylogenetic results, for now we adopt a conservative approach and adhere to generic concepts based on morphology.
Tropical African Ochnaceae have been treated in various Flora's (Bamps & Farron 1967, Hutchinson et al. 1954, Robson 1963, Verdcourt 2005).However, species occurring in the Lower Guinean area (part of the Guineo-Congolian floristic region, or phytochorion ;White 1979) remain without a proper taxonomic treatment to date.Although Farron (1965Farron ( , 1968Farron ( , 1985) ) published important contributions to the taxonomy of African Ouratinae, relevant for this area, our knowledge about this group remains highly incomplete.This information gap is seen in many other plant groups and is especially relevant in the light of the fact that the lowland rain forests of the Lower Guinean region (notably those in Cameroon and Gabon) are regarded as the most species-rich of tropical Africa (Mutke et al. 2001, Linder 2001, Küper et al. 2004, Sosef et al. 2006, Estrella et al. 2012, Linder et al. 2012).For this area, taxonomic revisions are indispensable, since in some cases they directly contribute to datasets that help prioritize conservation efforts (e.g.Burgess et al. 2005).The Flore du Gabon production tries to address the knowledge gap (Sosef & Florence 2007), but its existence as well as the extraordinary species richness of Lower Guinea is further emphasized by the fact that all species in African Oura tinae that have been described during the past 25 years (e.g.Sosef et al. 2007, Bissiengou & Sosef 2008, this publication) are endemic or sub-endemic to Gabon.Along with the fact that the botanical exploration of Gabon is far from complete (Sosef et al. 2006), this means that still many other novelties may be expected to emerge from Gabon's lush vegetation (see for example Walters et al. 2011).

MATERIALS AND METHODS
To perform the taxonomic revision of the genus Campylosper mum, herbarium material from the following herbaria has been consulted (acronyms follow Thiers 2012): A, B, BAS, BM, BR, 1 Naturalis Biodiversity Center (section NHN-Wageningen), Generaal Foulkesweg 37, 6703 BL Wageningen, The Netherlands. 2 Biosystematics Group, Wageningen University, Wageningen, The Netherlands. 3 Herbier National du Gabon, IPHAMETRA -CENAREST, Libreville, Gabon.All specimen data have been entered into the BRAHMS (Botanical Research and Herbarium Management System) database of the National Herbarium of the Netherlands (now part of the Naturalis Biodiversity Center).To perform an assessment of the IUCN category of threat for each taxon, the BRAHMS software was used in combination with ArcView 3.3 and the IUCN Red List add-in script developed by Moat (2007).Assignments follow the IUCN guidelines (IUCN Standards and Petitions Subcommittee 2011), but not the advice to set the cell width /height to 2 km.Instead, a sliding scale grid cell width is applied, which is deemed more appropriate for herbarium record data (Moat 2007).We define a 'location' as a single grid cell.All assignments will be send to IUCN for approval in the near future, which is why we characterize them as 'preliminary' for now.Understorey treelet up to 6 m tall.Stipules caducous, 3-5 mm long.Leaves: petiole 0 -2 mm long; leaf blade elliptic-obovate to oblanceolate, (9 -)14 -24(-31) by (4 -)6 -8(-11) cm, base auriculate to deeply cordate, often clasping the twig, apex acute, coriaceous to thick leathery, margin serrate, upper surface glossy green, lower surface dull paler green; midrib flattened above, prominent below, main lateral veins 10-20 mm apart, 16-19 on either side, curved upward to run parallel to the margin, intermediate lateral veins prominent on both sides, 0-2 in between each pair of main laterals, tertiary venation scalariform, very distinct on both sides.Inflorescences terminal or rarely axillary, its main axis 12-15(-18) cm long, flattened; racemes 1-6, 3-9(-11) cm long; pairwise scales absent; bracts persistent at the base of the raceme and pedicel, triangular, c. 3-5 mm long; cymules 5-9 mm apart, 2-4(-6)-flowered.Flowers: pedicel 5-7 mm, articulated at 2-3 mm from the base; sepals 5, ovate, in flower 7-8 by 2-3 mm, yellowish green, in fruit persistent and accrescent, 9-10 by 3-4 mm, bright red; petals 5, obovate, 7-12 by 3-4 mm, cuneate at base, rounded at apex, bright yellow; stamens 10, caducous, orange-yellow, filaments less than 1 mm long, anthers 3-4 mm long, transversely wrinkled, poricidal; ovary c. 2 mm wide; style c. 4 mm long, curved, yellow.Fruits: receptacle a ± flattened-globose shape, c. 5 mm wide, orange-red; drupelets 1-3 well developed per receptacle, reniform, c. 8 by 5 mm, black at maturity; cotyledons incumbent, dissimilar in size with a small outer cotyledon.
Ecology -In primary or secondary forest; on brown clay soil; at 475-600 m altitude.
Phenology -Flowers and mature fruits collected from October to November, flowers also observed in April, which coincides with the two rainy seasons.
Preliminary IUCN conservation status -VU B1/B2ab(ii, iii, iv).EOO = 6098 km 2 , AOO = 1653 km 2 , locations = 7 (cell width = 15.37 km).All collections have been made recently (the oldest one is from 1983).The only collection from Equatorial Guinea is from within a protected area (Inselberg at Akuom).The other ten collections from Gabon are from a fairly restricted area where logging companies operate which may lead to a decline in the AOO and/or extent of suitable habitat and hence we propose the 'Vulnerable' category.Note -Especially the auriculate to deeply cordate leaf base is highly reminiscent of C. schoenleinianum, a species confined to western tropical Africa (from Guinea to Ghana).
Ecology -In primary and secondary forest, sometimes along rivers or streams; at 70 -400 m altitude.
Phenology -Flowers observed from August to November and in April; fruits collected from October to January.
Preliminary IUCN conservation status -VU B1ab(ii, iii, iv).EOO = 4476 km 2 , AOO = 2348 km 2 , locations = 10 (cell width = 15.32 km).All known records of this taxon are from areas exposed to mining and/or logging activities rendering a projected decline in its AOO and/or quality of the habitat most likely and hence we propose the 'Vulnerable' category.subsp.australis Biss., subsp.nov.-Fig.2; Map 2 Diagnosis -Like the typical subspecies, but the leaf blade bullate between the lateral veins or rarely flat and the scalari form tertiary veins running perpendicular to the main lateral veins.
Ecology -In primary, moist and wet forest, in valleys with small streams; on sandy soil; at 3 -350 m altitude.
Phenology -Flowers observed from October to December; fruits collected from October to January.
IUCN conservation status -VU B1/B2ab(ii, iii, iv).EOO = 6862 km 2 , AOO = 1545 km 2 , locations = 10 (cell width = 12.43 km).This taxon is known only from 15 recent collections, five of which fall within the Loango National Park and the Moukalaba-Doudou National Park.The remaining ten collections originate from logging and oil concessions while even the Loango park is under development threat from Chinese mining companies.Therefore this subspecies is best placed in the category 'Vulnerable'.
Notes -This subspecies can be added to the list of taxa endemic to the greater Loango-Rabi area (Wieringa & Mackinder 2012).It is also an addition to the recently published checklist of Loango National Park (Harris et al. 2012), and provides further evidence for the unique vegetation in this part of Gabon (Wieringa & Sosef 2011).
Apart from the fact that the material shows a scalariform venation different from that of the typical subspecies, and a tendency to have more obviously bullate leaves, there seem to be no other differentiating characters.This, together with the parapatric distribution of the two entities, made us decide to distinguish the taxon at the subspecies level.
Distribution -Continental Equatorial Guinea (Rio Muni), Gabon and south-western Republic of the Congo (Niari).
Ecology -In primary and secondary forest, on creek banks and adjacent to swampy areas; at 210 -1000 m altitude.
Phenology -Flowers collected in January, April, July and August; fruits collected from March to May and in August.
Distribution -Endemic to Gabon, only found in the coastal plain, in the Ogooué-Maritime (Rabi-Kounga) and Estuaire (Mondah forest and Bikele) provinces.
Ecology -Primary and secondary, moist forest, near swampy areas; on sandy soil; at 5 -30 m altitude.
Phenology -Flowers collected from August to November, coinciding with the end of the long dry season and start of the main rainy season; mature fruits from November to December.
IUCN conservation status -VU.B1ab(ii, iii, iv).EOO = 5959 km 2 , AOO = 3388 km 2 , locations = 4 (cell width = 29.10km).This species seems to have a disjunct distribution, but this is uncertain because the area between the two occupied areas is not well explored.In a situation involving a disjunct distribution the sliding scale grid size method leads to an overly large estimation of especially the AOO.Some of the occurrences in the vicinity of the capital Libreville are under threat of habitat destruction due to urbanization and overexploitation.This is likely to lead to a decline in the area of occupancy and/or number of populations or even extent of suitable habitat and hence we propose the category 'Vulnerable'.', 27 Oct. 1991 (fl); J.J.F.E.de Wilde 9725 (WAG), 1 km on the road Rabi-Divangui, S1°54' E9°53 ', 25 Nov. 1989 (fr); Schoenmaker 135 (WAG), Rabi-Kounga, direction Echira, c. S1°59' E9°51 ', 11 Nov. 1991 (fl).
Note -The name Ouratea dusenii Engl.& Gilg, published in 1903, has been used most often in literature as the correct name for this species.Recently, Bissiengou & Sosef (2008) transferred that name to the genus Campylospermum.However, it now turns out that the name Monelasmum glomeratum Tiegh.(with type specimen Thollon 140) refers to the same taxon and is thus also available.Since it was published in 1902, hence one year before O. dusenii, Monelasmum glomeratum Tiegh.has priority which necessitates the new combination C. glomeratum (Tiegh.)Biss.
Map 4 Distribution of Campylospermum occidentalis Biss.Background indicates altitude.