Inversodicraea paulsitae (C.Cusset) Cheek

Tchouto, P. & Burgt, X. van der, 2017, A synoptic revision of Inversodicraea (Podostemaceae), Blumea 62 (2), pp. 125-156 : 138

11. Inversodicraea paulsitae (C.Cusset) Cheek

Inversodicraea paulsitae (C.Cusset) Cheek in Cheek & Haba (2016a) 2. — Ledermanniella paulsitae C. Cusset (1983) 378,f. 7. — Type: Le Testu 6510 (holotype P00179346 image; isotype BM), Gabon, ‘Moupoundi, rapide Litsila de la Ngounye’, fl., fr., 20 June 1927.

Etymology. Named for Paul Sita , pioneering Congolian forest botanist based at IEC, the National Herbarium of Congo-Brazzaville.He is the author of the first checklist of Congo Plants. He collected one of the original specimens of this species.

Distribution — Gabon, Congo-Brazzaville.

Habitat & Ecology — Dans les embruns, waterfalls; 350– 780 m altitude.

Conservation — Inversodicraea paulsitae is not listed on www.iucnredlist.org. It is known from only four locations (see above), equating to an area of occupancy of 4 km 2. The Moukoukoulou dam at Mindouli represents a threat to the location on the Bouenza. This dam provides power to Pointe Noire. Constructed in the 1970s, it is possible that the specimen collected at this site (Farron 4581) was made before the dam was constructed and that the species is now extinct at the site, since a survey mission there led by one of us (XVDB) in 2011 failed to find the species.

The location of the Sita 3581 seems to be in the region of the upper reaches of the Nyang at Niari in the Massif du Chaillu. The location of the Beckendorff s.n. location in Gabon, is equally uncertain. The type location, of Le Testu 6510, is on a tributary of the Ngounie. Since all three of these locations are not affected immediately by any known hydroelectric project that we have discovered, the species is probably extant, and possibly secure. However, as micro-hydroelectric projects expand in their geographic range, there is a distinct possibility that more of the locations for I. paulsitae may become threatened. The species is here assessed as Endangered, EN B2 ab(iii).

Additional specimens. CONGO-BRAZZAVILLE, Mouyondzi, chutes de la Bouenza S3°53' E13°42', fr., 2 Aug.1965, Farron 4581 (P00179347 image); ibid., Divenié , Mission Catholique ,sur rochers immergés dans la Bibaka, fr., 28 Jan. 1975, Sita 3581 (IRSC n.v., P00179348 image). – GABON, Riviere Louetoie, Chutes Byoko, 1933, J.J. Eckendorff s.a. ( BM) .

Notes — Similar and perhaps closely related to I. annithomae , the two being unusual in sharing long (5–25 cm), flexible, unbranched floating stems, with regular internodes, each node with a short, densely leaflet-clad flowering stem opposite to a long, dichotomously branched leaf. Inversodicraea paulsitae is easily separated from I. annithomae by the deeply trifid (not entire or with shallow, irregular, marginal teeth) scale-leaves.

The thick main axes are 10–12 cm long, unbranched except at the base. At anthesis they lack leaves, and bear flowers only from short, 2 mm long erect, densely leaflet-clad stems which are held in clusters of 4–12, the clusters are 5–10 mm diam on the upper side of the main axis.