Inversodicraea boumiensis (C.Cusset) Cheek (Cheek and Haba 2016: 55)

Bidault, Ehoarn, Boupoya, Archange, Ikabanga, Davy U., Nguimbit, Igor, Texier, Nicolas, Rutishauser, Rolf, Mesterhazy, Attila & Stevart, Tariq, 2023, Novitates Gabonenses 93: a fresh look at Podostemaceae in Gabon following recent inventories, with a new combination for Ledermanniella nicolasii, Plant Ecology and Evolution 156 (1), pp. 59-84 : 59

Inversodicraea boumiensis (C.Cusset) Cheek (Cheek and Haba 2016: 55)

Figs 3C , 4A

Ledermanniella boumiensis C.Cusset ( Cusset 1983: 370, plate 3)

Type.

GABON • Boumi waterfalls at Mbigou [" Chutes de la Boumi à Mbigou"]; 5 Jul. 1927; [1°54 ’16” S, 11°54 ’31” E]; 665 m; fl., fr.; Le Testu 6536; holotype: P [P00179270]; isotypes: BM [BM000910485], BR [BR0000006267230], P [P00179271] .

Distribution.

Endemic to the Louétsi river, south-eastern Gabon. Before 2017, this species was only known from a single collection made at Boumi falls, near Mbigou. In 2018, it was discovered at two additional sites on the same river, at Issala and Dibwangui.

Habitat and ecology.

Rapids and falls in rivers from ca 30 to 50 m wide, 380-665 m in elevation. It appears to be very rare at the sites where it has been encountered. Flowers and fruits were collected in July and August. At Dibwangui, it grows intermingled with I. aff. annithomae , in strong currents.

Notes.

Inversodicraea boumiensis can be distinguished from I. annithomae mainly by its much smaller stature (stem <1 mm thick and up to 2-3 cm long vs stem up to 3 mm thick and 20 cm long), stem scales (thin and spreading in I. boumiensis vs thick and appressed in I. annithomae ), and pollen as dyads (vs monads in I. annithomae ). The collection Letouzey 15339 from the Ntem river (Cameroon) was attached to I. boumiensis by Cusset, but later determined as I. tchoutoi ( Cheek et al. 2017). After examination of this collection, we choose to follow Cheek et al. (2017).

Figures

Figure 3. Photographs illustrating a selection of species treated in this paper. A, B. Inversodicraea annithomae (A: Boupoya et al. 2444; B: Boupoya et al. 2689). C. Inversodicraea boumiensis (Boupoya et al. 1748). D, E. Inversodicraea nicolasii (D: Texier et al. 2247; E: Texier et al. 2334). F, G. Inversodicraea paulsitae (Boupoya et al. 1750). H, I. Inversodicraea tenax (H: Boupoya et al. 2432; I: Boupoya et al. 2430). Photographs: Igor Nguimbit (A), Archange Boupoya (B, C, F-I), Nicolas Texier (D, E).

Figure 4. Distribution maps of Podostemaceae in Gabon. A. Inversodicraea annithomae (grey circles), I. boumiensis (red diamonds). B. Inversodicraea nicolasii (red diamonds), I. paulsitae (grey circles), I. tenax (orange triangles). C. Inversodicraea thollonii (red diamonds), Ledermanniella bifurcata (grey circles). D. Ledermanniella aloides (grey circles), L. schlechteri (red diamonds).