Inversodicraea achoundongii J.J.Schenk, Herschlag & D.W.Thomas, 2015

Tchouto, P. & Burgt, X. van der, 2017, A synoptic revision of Inversodicraea (Podostemaceae), Blumea 62 (2), pp. 125-156 : 142-143

22. Inversodicraea achoundongii J.J.Schenk, Herschlag & D.W.Thomas

Inversodicraea achoundongii J.J.Schenk, Herschlag & D.W.Thomas (in Schenk et al. (2015) 542). — Type: D.W. Thomas 9642 & G. Achoundong (holotype MO n.v.; isotypes GAS n.v., K, NO n.v., YA, Z n.v.), Cameroon, South Region , forest and banks of Ntem River, W of Nyabessan, herb on rocks, stem flattened, creeping, N02°24' E10°22', 1 Dec. 1992.

Etymology. Named for Dr Gaston Achoundong,former head of the IRADNational Herbarium of Cameroon (YA), Secretary-General of AETFAT and noted specialist in Rinorea and co-collector of the type specimen.

Distribution — Cameroon, Memve’ele Falls, Ntem River; c. 395 m altitude.

Habitat & Ecology — Along the Ntem River, where the river breaks into multiple channels and goes over an escarpment in multiple waterfalls at Memv’ele, flowering as the water level recedes in the dry season.

Conservation — Known only from the type locality at the Memve’ele Falls on the Ntem River, site of the Memve’ele Hydropower project. Financed by China Exim Bank, and constructed by Sinohydro for the Ministry of Power and Water Resources Cameroon, this is designed to have a 200 MW ca- pacity from a reservoir of 19 million m 3 resulting from an earthfill dam 20 m high built across the top of the falls, diverting water from the falls through a turbine house (https://www.esi-africa. com/cameroon-and-sinohydro-partner-for-the-memve-elehydropower-station-project/ accessed 15 Feb. 2017). This project is expected to have highly negative effects on the survival of I. achoundongii since the dam will ‘direct the flow of the river away from the multiple waterfalls … This dam will disrupt the hydrology of the site by destroying many waterfalls and flooding or filling the rocky reach of the river above the falls”. ( Schenk et al. 2015 in describing I. achoundongii ). These authors continued “our new species fits the IUCN criteria for Critically Endangered and could soon become extinct because of the dam construction and operation”.

Schenk et al. (2015) also cite an earlier conservation assessment of another Podostemaceae species at the same site: “In the IUCN (2012) Endangered listing for Inversodicraea annithomae [the Cameroon material is now I. tchoutoi ] known only from the type locality in Gabon and from the Chutes de Memve’ele, Jean-Paul Ghogue wrote: The major threat to this species in Cameroon is the dam construction planned in the only site locality of this species, the Ntem Waterfalls at Memve’ele near Nyabizon, 60 km east of Campo”.

Since I. achoundongii is only known from a single location, with an estimated AOO of 1 km 2 and with threats as cited above, using IUCN (2012), we here assess its conservation status as CR B1+2ab(iii), that is Critically Endangered, confirming the assessment of Schenk et al. (2015). The species is not listed on www.iucnredlist.org.

Note — Inversodicraea achoundongii is notable in the genus for its: 1) small stature: plants are usually <1 cm tall and can flower at only 5 mm tall ( Schenk et al. 2015: f. 1); and 2) the primarily deltoid (equilaterally triangular) scale-leaves which are not imbricate, but only thinly scattered on the stems.