Inversodicraea harrisii (C.Cusset) Cheek

Tchouto, P. & Burgt, X. van der, 2017, A synoptic revision of Inversodicraea (Podostemaceae), Blumea 62 (2), pp. 125-156 : 136

7. Inversodicraea harrisii (C.Cusset) Cheek

Inversodicraea harrisii (C.Cusset) Cheek in Cheek & Haba (2016a) 2. — Ledermanniella harrisii C. Cusset (1983) 374, f. 5. — Type: Harris 41 (P00179305 image holotype), Sierra Leone, rapids at Dodo ferry crossing to Magbwema, river Sewa, N7°50 " W11°44 ", fl., fr., 8 Dec. 1981.

Etymology. Named for Prof.P.J.C.Harris,Agricultural Scientist,University of Coventry, United Kingdom, the collector of the type specimen and most of the original material.

Distribution — Guinea-Conakry ( Republic of Guinea) and Sierra Leone.

Habitat & Ecology — Rapids in rivers of evergreen forest areas; 60–280 m altitude.

Conservation — Inversodicraea harrisii is not listed on www. iucnredlist.org. Five locations are known (above), equating to an area of occupancy of 5 km 2. Its location in Guinea on the Bafing River is threatened by the planned Koukoutamba dam for which construction bids were sought in 2016 (https://www. africa-energy.com/article/guinea-omvs-develop-koukoutambahydro-scheme accessed 17 Feb. 2017). This threatens the species through both permanent flooding and arresting of the flow of water in the reservoir part of the project, and the disruption of the natural cycle of water levels below the dam. The second location, on the Sewa River, is thought to be threatened by high levels of diamond extraction upriver, which places silt into the water, reducing both seedling establishment and photosynthesis for Podostemaceae downstream. Finally, the location at the site of the Bumbuna-Yiben hydroelectric dam is thought to be in the process of being lost. Accordingly the species is here assessed as Endangered, EN B2 ab(iii).

Additional specimens. GUINEA-CONAKRY, Haut Bafing , près Socotoro , fr., Apr.1905, Chevalier s.n. (holotype P00179299 image).– SIERRA LEONE, rapids of the river Sewa at Dodo to Magbwema , N7°50 " W11°44 ", fl., fr., 8 Dec. 1981, Harris 41 (P00179305 image holotype); ibid., Harris 37 (P00179301 image); ibid., Harris 38 (P00179302 image); rapids near Mofwe , River Sewa , N7°40 " W11°58 ", 8 Dec. 1981, Harris 34 (P00179300 image); River bridge near Baiima , River Tabe N8°06 " W11°51 ", 8 Dec.1981, Harris 46 (P00179303 image); Road bridge 2 miles SW of Lengkoro, River Mawaloko , N9°27 " W11°42.4 ", 10 Dec. 1981, Harris 71 (P00179304 image); Koinadugu District , SE of Fadugu,along Seli (Rokel) river east of Fadugu,upstream of the village of Yiben, to be flooded by proposed dam N9°18'52.2" W11°39'27.5", 260 m alt., old fr., 31 May 2014, van der Burgt 1840 (BR n.v., K, MO n.v., P n.v., SL n.v., WAG n.v.) .

Notes — Unique in West African species of the genus in the single dorsal tooth of the leaflet, more or less equal in size to the lateral teeth-lobes. Those few other species with dorsal projections have much smaller and more irregular protuberances, and none occur in West Africa.

The figure in the protologue ( Cusset 1983) shows all of the scale-leaves with the distinctive dorsal spine. However, recent specimens from the Bumbuna area of Sierra Leone such as van der Burgt 1840 (initially identified as L. ledermannii ) have only one in five, or one in ten scale-leaves with the spine. It is not clear whether this is because of variation in the frequency of expression through the population, or whether another explanation, such as hybridisation and introgression with I. ledermannii , which also occurs at this location, might be the cause. Alternatively the figure in Cusset (1983) may be errone- ous, but this cannot be checked against the original material, all at P, without a physical visit, since resolution of the online digital images is too low for this purpose.