A NEW SPECIES OF CAMPYLOSPERMUM ( OCHNACEAE ) FROM COASTAL GABON

In 2005, during fieldwork in the Loango National Park in coastal Gabon, the second and third author, along with R. Niangadouma of the National Herbarium of Gabon (LBV), made two collections of a peculiar Campylospermum. When, in 2006, it was shown to the first author in Wageningen he could not match it with any species present in the recently published Checklist of Gabonese vascular plants (Sosef et al., 2006) nor with any other described in the works of Farron (1965, 1985) and Bamps & Farron (1967) and concluded it must represent a new species. A search through the Gabonese material of the family at WAG and MO revealed two other collections of the same species, both from coastal regions further south.


INTRODUCTION
In 2005, during fieldwork in the Loango National Park in coastal Gabon, the second and third author, along with R. Niangadouma of the National Herbarium of Gabon (LBV), made two collections of a peculiar Campylospermum.When, in 2006, it was shown to the first author in Wageningen he could not match it with any species present in the recently published Checklist of Gabonese vascular plants (Sosef et al., 2006) nor with any other described in the works of Farron (1965Farron ( , 1985) ) and Bamps & Farron (1967) and concluded it must represent a new species.A search through the Gabonese material of the family at WAG and MO revealed two other collections of the same species, both from coastal regions further south.
Recently, various botanical expeditions to the Loango National Park have shown that, in addition to being a remarkable site for vertebrate wildlife, it is also of significant botanical interest illustrated by the recent discovery of several species new to science, such as Berlinia razzifera MacKinder & Wieringa ined., Cassipourea maritima Breteler ined., Anthonotha spec.nov.and now a new species of Campylospermum.It is highly likely that several other new species with restricted distributions remain to be discovered.All this confirms the rightful attribution of the status of National Park to this area by the authorities in Gabon.The zone is acknowledged by IUCN as a critical site for conservation.Moreover, Loango is a Ramsar site and has recently been proposed as a World Heritage Site (http://www.operation-loango.com/loango_national_park_gabon.html).
This new species of Campylospermum is easily recognized by its comparatively small, narrowly elliptical leaves with no or very few secondary veins and dense parallel tertiary venation as well as its short inflorescences.Upon first glance, the tertiary venation is reminiscent of leaves found in the genus Rhabdophyllum, for which the first author is finalizing a revision, but the perpendicular cross-veins connecting them reveal that it does not fit there.The species seems most closely related to Ouratea dusenii Engl.& Gilg (for which no valid combination within the genus Campylospermum exists yet).It differs in having fewer secondary veins, an apiculate leaf tip, a distinct marginal vein and an even shorter inflorescence with less flowers per cymule.The narrow leaves and lack of secondary veins are also reminiscent of C. lecomtei (Tiegh.)Farron from the Democratic Republic of Congo, but the material is clearly distinct from this species due to its less narrow leaves, shorter and broader (non-linear) stipules and much shorter inflorescence.
A closer look at the seeds revealed accumbent, strongly unequal cotyledons, with the reduced cotyledon external, rendering our species a member of the section Monelasmum (Tiegh.)Farron rather than section Bisetaria (Tiegh.)Farron in which C. lecomtei is the only species (Farron, 1968).Shrub-like treelet of up to 2 m high.Young twigs markedly, longitudinally furrowed.Leaves: stipules caducous, narrowly triangular; petiole 0-2 mm long; leaf blade leathery, narrowly elliptical, 3-9.5 by 0.7-2.1 cm, attenuate at base, apex apiculate, margin entire in the lower half to lower third, distal part with distant small teeth, upper surface glossy dark green, lower surface slightly paler, venation prominent on both surfaces (in sicco), the midrib markedly so; secondary veins absent or only 1-2(-5), branching off in the lower part of the leaf and strongly curved upwards to form a prominent marginal vein which runs just inside the margin of the blade; tertiary veins closely spaced and parallel, joined by perpendicular cross-veins.Inflorescence terminal, without or with few paired bracts at the base, composed of 1-3 short racemes of up to 1.5 cm long; cymules with 1 (or 2) flower(s), each cymule with a persistent, small, triangular to narrowly triangular bract of up to 1 mm long at its base.Flowers with a 7-12 mm long pedicel, articulating at 1-3 mm from the base; sepals narrowly elliptic-ovate, c. 5 by 2 mm, rounded at apex, yellowish green, in fruit expanding to c. 6 mm and bright red; petals broadly spathulate, 6-8 by 3.5-5 mm (larger measurements taken from photos), bright yellow; stamens 10, c. 4 mm long; style c. 4 mm long.Fruit: receptacle ± globose, bright red; drupelets only 1 or 2 well-developed per receptacle, ± globose, 5-6 mm diam., black.Seed: cotyledons accumbent, strongly unequal with the reduced cotyledon external.

Fig. 2 .
Fig. 2. Twig of Campylospermum paucinervatum Sosef showing leaves with few secondary veins and red sepals and receptacle of infructescence.Photo by D.J. Harris.