Inversodicraea fluitans H.Hess

Tchouto, P. & Burgt, X. van der, 2017, A synoptic revision of Inversodicraea (Podostemaceae), Blumea 62 (2), pp. 125-156 : 139

13. Inversodicraea fluitans H.Hess

Inversodicraea fluitans H. Hess (1953) 364. — Ledermanniella fluitans (H.Hess) C. Cusset (1974) 273;(1983) 382. — Type: Hess 50/83 (isolecto- types BM 2 sheets, BR n.v., G n.v.; lectotype ZT), Angola, Malanje, ‘…den Fällen von Bragança (Rio Lucala), im Norden von Angola, am 28.7.1950 gesammelt. Die Pflanze werd nur am obern Band der Fälle im ressenden Wasser flutend beobachtet. Sie hat sich dort an Graniten festgesetzt. Höhe zirka 1200 m. Auf Falsen am oberen Ronde der Fälle’, alt. 1200 m, fl., fr., July 1950.

Etymology. Presumably referring to the stems which flow in the current of water.

Distribution — Angola.

Habitat & Ecology — Waterfalls in open, mainly woodland habitat sometimes with Hydrostachys polymorpha (type locality); 50–1200 m altitude.

Conservation — Inversodicraea fluitans is not listed on www. iucnredlist.org. It is known from one location on the Lucala River (tributary of the Kwanza), the Chutes de Bragança (now the Kalandula Falls), and at two locations on the Kwanza (Cuanza) River, at Cassoque-Cabrita, and at Cambambe-Dondo. Using the IUCN-preferred 1 km 2 cells for riverine species results in an area of occupancy of 3 km 2. Existing threats on the Kwanza are immense. At 2014 the 520-MW Capanda, 700-MW Cambambe 2, 2067-MW Lauca, and the 260-MW Cambambe were already in place or under construction. Studies for Caculo- Cabaca, Zenzo 1, Zenzo 2, Tumulo do Cacador and Luime new hydroelectric power projects were conducted in 2014 according to Estevao. The Lauca project is under construction by the Brazilian company Odebrecht. The five new projects are to be constructed by Coba (https://constructionreviewonline. com/2014/10/angola-carry-five-hydroelectric-projects/ downloaded 16 Feb. 2017). Therefore at least two, and possibly all three known sites for this species are probably threatened. We here assess the species using IUCN (2012) as Endangered, EN B2 ab(iii).

Additional specimens. ANGOLA, Malanje, Duque de Bragança , Luando Muba, Lucata , 1000 m, 29Aug.1922, Gossweiler 8855 ( BM) ; ibid., Rianondo , 1 Sept. 1922, Gossweiler 8856 ( BM) ; ibid., Loando Muba , 1000 m, 29 Aug. 1922, Gossweiler 8857 ( BM) ; ibid., Quedes de Duque de Bragança [Quedas de Kalandula], E16°01' S9°04', 23 Mar.1973, 1140 m, Bamps, Martins, M. Silva 4259 (P00179286 image) ; Cuanza Norte / Bengo, Cambambe-Dondo, Cata- rata Cuanza , 55 m,fl., Gossweiler 9247 ( BM) ; bridge on R. Cuanza [Kwanza], Cassoque-Cabrita ,fr., 25 June 1937, Exell & Mendonca 3086 (BM, COI n.v.) .

Notes — Although Cusset (1983) stated that the holotypes of Hess’s 1953 names are at ZT, specimen locations are not given in the protologue, so lectotypification is needed. The ZT duplicate is therefore formally selected as lectotype since Hess is believed to have been based there.

Similar to the more frequently recorded I. warmingiana (see there for diagnostic characters), I. fluitans is only known from three locations, all in Angola, at one of which I. warmingiana has also been recorded (bridge on R. Cuanza, Cassoque-Cabrita, Exell & Mendonca 3085, 3086, COI n.v.).

While the type has 80 cm long, flowing stems and almost digitate lobes at the apex of the oblong scale-leaves, the remaining specimens are shrubby, with pectinate lobes. The long laciniate, narrow, acute lobes are similar in some respects to those of I. cristata . However, in the 5–7-toothed scale-leaves this species is closest to sympatric I. warmingiana , which is distinguished primarily by the 6-winged apex of the fruit.