Habenaria geerinckiana (Schaijes) Geerinck, Taxonomania, 2007

Bytebier, Benny & Wightman, Nicholas, 2022, Habenaria geerinckiana (Orchidaceae), an updated description, extended distribution and conservation assessment, Phytotaxa 544 (2), pp. 223-226 : 223-226

Habenaria geerinckiana (Schaijes) Geerinck, Taxonomania 20: 18 (2007).

Basionym: Kryptostoma geerinckiana Schaijes in Geerinck & Schaijes, Bull. Jard. Bot. Nat. Belg., 57: 483 (1987).

Type :— DR CONGO. Katanga, W of Kolwezi, 23 Nov 1985, Schaijes 2697B (holotype: BR0000008814043!) .

Terrestrial herbs 25–40 cm tall. Tubers 3–4 × 1–2 cm, ovoid to ellipsoid, woolly. Leaves 5–10; the lowermost spreading, 2.5–3.0 × 2.0 cm, ovate; the next few suberect, up to 6.0 × 2.5 cm, lanceolate, acute; the upper ones grading into the bracts. Inflorescence 8–13 × 5–6 cm, laxly 4–7-flowered; bracts 10–30 mm long, lanceolate, reaching half the length of the ovary. Flowers green. Pedicel and ovary 15–30 mm long, ± straight. Dorsal sepal 12–15 × 15 mm, ovate, convex, projecting over column, tip recurved; lateral sepals projecting forwards, c. 13 × 4 mm, obliquely lanceolate, adnate to column and base of spur. Petals erect, bilobed, with an undivided basal part of 5–7 mm; posterior lobe 13–15 × 2–3 mm, lanceolate, the margins ciliate, adnate to dorsal sepal; anterior lobe 18–22 × 1 mm, linear, horn-shaped above the dorsal sepal. Lip trilobed, the base adnate to the column for about 5 mm; midlobe 7–10 × 1 mm, linear, reflexed; side lobes 15–20 × 1 mm, linear, curving forwards; spur c. 20 mm long, pendent, slightly recurved, apex slightly swollen. Anther locules c. 2 mm, reclinate, joined by a U-shaped connective c. 3 mm high, 7 mm long; anther canals c. 4 mm, upcurved; stigmatic arms 4–5 mm, clavate, decurved.

Habitat:— Although Flore d’Afrique Central ( Geerinck, 1992) mentioned the habitat as “galleries forestières”, on the type specimen and in the protologue it is described as “savanne steppique” or “savanna grassland.” The latter fits better with our habitat observations, i.e. watershed plains grassland within a diverse suffrutex community (DR Congo; Fig. 1 ) and on drier upper slopes of large open dambo ( Zambia).

Conservation status assessment:— Habenaria geerinckiana is a restricted species known from only three georeferenced collections representing two extant subpopulations, one in south-western DRC (Kolwezi District) and one in north-western Zambia (Mwinilunga District). Using these locations, the extent of occurrence (EOO) was estimated to be 3931 km 2 and the area of occupancy (AOO) 3 km 2, both of which are within the threshold for endangered status under criteria B1 and B2. This was calculated using the web-based Geospatial Conservation Assessment Tool (GeoCAT; Bachman et al., 2011). AOO was calculated based on a user-defined cell size of 1 km 2, which more accurately reflected the size of the habitat patches available at the three known localities than the IUCN default cell size of 4 km 2. The watershed plain grassland habitat in Kolwezi district has declined in extent and quality as a result of mining projects and expanding urbanisation from Kolwezi. It can be inferred that the Kolwezi subpopulation has also declined as a result, both in spatial extent occupied and number of mature individuals. The proposed conservation assessment of this species is EN B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v).

Specimens examined: — DR CONGO. Katanga (Lualaba): west of Kolwezi, 10°47’30’’S, 25°17’01”E, 1490 m, 23 Nov 1985 Schaijes 2697B (BR0000008814043, photo!, holotype); south-west of Kolwezi , 10°47’11.82”S, 25°17’12.97”E, 1512 m, 22 Nov. 2021, McCleland, no specimen collected, images stored on iNaturalist at https://www.inaturalist.org/ observations/108490995, see also Fig. 2 ). ZAMBIA. North-Western: Mwinilunga, Muwana, Muchana Dambo , 11°24’12.7”S, 24°40’42.8”E, 1375 m, 10 Jan 2019, Wightman NcW 118 (K!, NDO!, NU spirit!; Fig.3 ) .

Figures

FIGURE 1. Photograph of watershed plains habitat of Habenaria geerinckiana, Kolwezi, DRC (by W. McCleland).

FIGURE 2. Photographs of Habenaria geerinckiana, Kolwezi, DRC (by W. McCleland).

FIGURE 3. Photograph of the Zambian H. geerinckiana specimen (Wightman NcW 118) (reproduced with permission of the Bews Herbarium, NU).