Carapa wohllebenii Eb.Fisch, Killmann, Leh & S.B.Janssens, 2021

Fischer, Eberhard, Killmann, Dorothee, Leh, Burkhard & Janssens, Steven B., 2021, Carapa wohllebenii (Meliaceae), a new tree species from montane forests in the Democratic Republic of Congo, Rwanda, and Burundi, Phytotaxa 511 (1), pp. 20-36 : 23-28

Carapa wohllebenii Eb.Fisch, Killmann, Leh & S.B.Janssens , sp. nov. ( Figs 2 A–B , 3–6 , 10 )

Type: — RWANDA. Western Province. Nyungwe National Park, Gisakura , close to tea plantation, 1873 m, 18 September 2016, Fischer 758/16 (holotype BR!; isotypes NHR!, KOBL!) .

Diagnosis: — Carapa wohllebenii is morphologically similar to C. grandiflora , but differs in the shape of the leaflets (oblanceolate-oblong with distinctly mucronate apex vs. oblong-ovate with mucronulate apex bearing a short acumen in C. grandiflora ), the length/width ratio of 3.2–4.7 (vs. 1.9–2.7 in C. grandiflora ), and the more narrow petals (4.5 vs. 5.5–6.5 mm in C. grandiflora ) and the slightly larger fruits (9.4–10.5 vs. up to 7.4 cm in C. grandiflora ).

Description: —Tree up to (7–)10–20(–30) m tall. Stem with up to 80 cm dbh; bark thin; branches arching downwards. Leaves up to 62–68(–80) cm long; petiole 16.0– 19.4 cm long, base swollen; rachis 22–27 cm long, glabrous; leaflets (3–)4–6 pairs, oblanceolate-oblong, apical leaflets 18.5–25.0 × 4.5–5.9 cm, apex distinctly mucronate, midrib prominent, secondary veins 5–7 pairs; petiolule 0.4–0.6(–0.7) cm long. Inflorescences borne in axils of fully developed leaves, up to 30 cm long, erect, sparsely branched, branches green. Flowers 5-merous, distinctly pedicellate, pedicel 2.5–3.5 mm long; calyx greenish, glabrous, (1.5–)1.8–2.0 mm in diam., lobes (0.8–)1.0–1.5 × (1.5–) 1.8–2.2 mm; petals 4.2–5.5 × 4–5 mm, green tinged with red; staminal tube 3.5–4.5 mm in diam., 3.5 mm high, 10-lobed, lobes 1.0– 1.5 mm long, anthers/antherodes 0.8 × 0.8–0.9 mm; ovary 3.0– 4.5 mm in diam. in female flowers, stigma 2.2–2.5 mm in diam., 2–3 mm in male flowers; locules 2-ovulate. Fruit 9.4–10.5 cm in diam., spherical, green turning brown. Seeds 5.0–5.7 × 3.7 cm, 8–10 per fruit.

Etymology: —The species is named after Peter Wohlleben [1964–], German forester and author, in recognition of his enthusiasm for trees and nature conservation. His books (e.g. Wohlleben 2017) inspired millions of readers worldwide and significantly changed their views on forests and trees in a positive way.

Habitat: —The species grows in the shrub and tree layer of a submontane to montane rainforest.The accompanying vegetation consists of the following dominant species: Tree layer: Entandrophragma excelsum Sprague (1910: 180) (Meliaceae) ; Grewia mildbraedii Burret (1909: 344) (Malvaceae) ; Newtonia buchananii (Baker) Gilbert & Boutique (1952: 213) [= Piptadenia buchananii Baker (1894: 354) ] ( Fabaceae ). The species occurs from (1 350–)1 800–2 500 m.

Distribution: —Only known from the Albertine Rift in Democratic Republic of Congo on the Western Crest near Albert Lake and Kivu Lake (mainly Kahuzi-Biéga National Park), in Rwanda (Gishwati-Mukura-National Park, Nyungwe National Park), and in Burundi (Kibira National Park).

Conservation status (preliminary): —Despite potential threat by logging, the majority of populations occurs in protected areas. Thus the preliminary assessment should be LEAST CONCERN (LC) according to the IUCN criteria ( IUCN 2016).

Additional specimens examined (paratypes):— DEMOCRATIC REPUBLIC OF THE CONGO. Lacs Édouard et Kivu: Mushari-Est, colline Kavumu, 01 February 1952, Spitaels 436 ( BR) ; Forêt de la Musisi, km 21 route Kavumu-Walikale, 06 February 1959, Pierlot 2681 ( BR) ; Mulanga , km 128 route Bukavu-Shabunda, 27 September 1958, Pierlot 2547 ( BR) ; Kikoma , km 50 route Kibabi-Kikoma, 29 April 1958, Pierlot 1934 ( BR) ; Gombo , 19 August 1949, Liégeois 290 ( BR) . Lac Albert: Route Gabu Golu , village Logu, 03 December 1948, Taton 853 ( BR) ; Route Gabu Golu ( Kima-Kima ), 13 December 1947, Taton 772 ( BR) ; Nioka Réserve Inéac, Riv. Kada , 05 October 1946, Taton 372 ( BR) ; Région de la rivière Denge, 26 June 1959, Deville 505 ( BR) . RWANDA. Lacs Édouard et Kivu: Gishwati-Mukura National Park: Gisenyi [=Rubavu]- Kibuye [=Karongi] km 40, 18 January 1972, Bamps 2959 ( BR) ; Gisenyi-Kibuye , km 39, 20 February 1972, Bamps 3195 ( BR) ; Mukura , 20 September 1972, Van Puyvelde 73 ( BR) ; Ihembe , 29 August 1952, Schedl 776 ( BR) . Nyungwe National Park: Forêt de Rugege-Crête Congo-Nil , 24 February 1955, Reynders 23 ( BR) ; Route Bukavu-Astrida [=Butare, Huye], environ de Wakagano, 06 April 1959, Troupin 9735 ( BR) ; Forêt de Rugege , au km 107 de la route Butare-Cyangugu, 15 August 1974, Auquier 3774 ( BR) ; Forêt de Nyungwe , marais de Kamiranzovu, 26 January 1971, Bouxin 192 ( BR) ; Forêt de Nyungwe , environs de Mayembe, 20 January 1971, Bouxin 66 ( BR) ; Forêt de Nyungwe , environs d’Uwinka, 26 June 1971, Bouxin A 14 ( BR) . BURUNDI. Lacs Édouard et Kivu: Kibira National Park. Teza, 14 January 1980, Reekmans 8545 ( BR) ; Prov. Muramvya, Teza , 2100, Reekmans 8545, 14 Jan. 1980 ( BR) ; Bugarama , 25 June 1966, Lewalle 1021 ( BR) ; Kungoboka, Ruhondo ( Rwegura ), 10 December 2012, Nzigidahera 6 ( BR) .

Specimens examined of Carapa grandiflora Sprague in Stapf (1906: 507)

Type:— UGANDA. U2: West Ankole Forest , 1500 m, Dawe 351 (holotype K!)

Other specimens examined:— DEMOCRATIC REPUBLIC OF THE CONGO. Lacs Édouard et Kivu: Mt. Bukulumiza Inéac-Mulungu , 16 September 1952, Pierlot 292 ( BR) ; Luzira , April1932, Lebrun 5395 ( BR) ; Mumo , 21 January 1959, Léonard A. 2677 ( BR) ; Kahuzi , 11 March 1959, Léonard A. 3417 ( BR) ; Kimbili, abords route Cost. [=Bukavu]- Shabunda au km 265, 06 January 1949, Michelson 837 ( BR) ; Bitale, Coupe de bois Deum , km 48 route Kavumu-Walikale , 21 September 1956, Pierlot 1362 ( BR) ; Mahanga , 16 December 1958, Léonard A. 2029 ( BR) ; Environs de Kapanga, MGL Sud , division cassitérite, 06 December 1947, Michelson 728 ( BR) ; Sud-Kivu, Kabalukwa , 25 April 1996, Bashonga M.G. 444 ( BR) . RWANDA. Lacs Édouard et Kivu: Gishwati-Mukura National Park, Gisenyi [=Rubavu]- Kibuye [=Karongi] km 40, 18 January 1972, Bamps 2959 ( BR) ; Nyungwe National Park, Cyamudongo Forest , 5 December 2012, Fischer 633/12 ( KOBL) ; Forêt de Nyungwe, Région de Gisakura , 25 August 1969, Bouxin & Radoux 801 ( BR) ; Route Astrida (= Butare)- Bukavu vers km 93, marais Kamiranzofu [=Kamiranzovu], 14 October 1959, Troupin 11199 ( BR) ; Forêt de Nyungwe, environs d’Uwinka , 21 January 1971, Bouxin 77 ( BR) ; Forêt de Nyungwe , environs de Kingogo, 26 May 1971, Bouxin 925 ( BR) ; km 117 de la route Astrida [=Butare, Huye]- Shangugu [=Cyangugu, Rusizi], Chefferie Bukunzi , 20 June 1957, Reynders 103 ( BR) ; Nyongwe à 8 km au sud de km 87 de la route Astrida-Shangugu , 16 July 1957, Reynders 123 ( BR) ; km 116 de la route Astrida-Shangugu , 09 July 1956, Reynders 213 ( BR) ; Ihembe , 29 August 1952, Schedl 758 ( BR) . BURUNDI. Lacs Édouard et Kivu: Bururi, Vallée de la Sikuvyaye [=Siguvyaye], 08 April 1969, Lewalle 3463 ( BR) ; Munini (Mashuha), source de la Sikuvyaye [=Siguvyaye], 22 September 1974, Auquier 4186 ( BR) ; Rives de la Sikuvyaye [= Siguvyaye ], 02 May 1966, Lewalle 760 ( BR) ; Kumuyange , 08 May 1971, Lewalle 5680 ( BR) ; Rutovu , 21 September 1973, Reekmans 2767 ( BR) ; Rwanda-Burundi, Nkundaraje, route Gitega-Ruyigi , km 32 pont de la Nyakijanda, 11 October 1978, Reekmans 7149 ( BR) ; Muhweza , 5 km est Cankuzo, 04 May 1980, Reekmans 9080 ( BR) .

Note: — Carapa grandiflora s.str. is here for the first time recorded for the Democratic Republic of Congo. The specimen Pierlot 292 from BR ( BR 0000013976743) represents C. grandiflora , while a specimen on JSTOR with the same collector and number (not studied by us) at MLGU ( MLGU 24370298) is a different species and probably represents C. wohllebenii .

Figures

FIGURE 2. Leaf and leaflet shape. A–B. Carapa wohllebenii. A. Bouxin 192. B. Fischer 758/16 (holotype). C–D. Carapa grandiflora. C. Fischer 633/12. D. Dawe 351 (holotype). Drawings by D. Killmann. Scale bar: 5 cm.

FIGURE 3. Carapa wohllebenii. A, C. Branches with leaves and fruits. B. Leaf. Photographs: E. Fischer. A. Rwanda, Uwinka, 24 September 2015. B. C. Butare, 3 January 2016. Scale bar:A. 10 cm; B, C. 5 cm.

FIGURE 4. Carapa wohllebenii. A. Shoot with flowers. B. Inflorescence. C–F. Flowers. Photographs: E. Fischer, Rwanda, Gisakura, 18 September 2016. Scale bars: A, C–F. 5 mm; B. 5 cm.

FIGURE 5. Carapa wohllebenii. A. Shoots withleaves.B. Shoots with young leaves.C. Fruit.D. Fruitopened showing seeds.Photographs: E. Fischer, Rwanda, Nyungwe National Park. A. Gisakura, 18 September 2016. B. Uwinka, 17 March 2017. C. Uwinka, 24 September 2015. D. Kamiranzovu, 11 September 2005. Scale bars: A–B. 10 cm; C–D. 5 cm.

FIGURE 6. Carapa wohllebenii. Holotype in Herb. BR, inflorescence kept separate in spirit. Reproduced with permission of the Botanic Garden Meise.

FIGURE 10. Known distribution of Carapa wohllebenii and Carapa grandiflora. Dots represent only the examined specimens. Carapa grandiflora is additionally represented by two further localities in southwestern Uganda and one in western Tanzania close to Lake Tanganyika (specimens not examined).