Uvariodendron gorgonis Verdc., Kew Bull. 23(3): 512 (1969)

Dagallier, Leo-Paul M. J., Mbago, Frank M., Couderc, Marie, Gaudeul, Myriam, Grall, Aurelie, Loup, Caroline, Wieringa, Jan J., Sonke, Bonaventure & Couvreur, Thomas L. P., 2023, Phylogenomic inference of the African tribe Monodoreae (Annonaceae) and taxonomic revision of Dennettia, Uvariodendron and Uvariopsis, PhytoKeys 233, pp. 1-200 : 1

Uvariodendron gorgonis Verdc., Kew Bull. 23(3): 512 (1969)

Figs 24 , 25 , 26

Type.

Kenya - Coast • B. Verdcourt 3940 (holotype: K! (K000198893), sheet here designated; isotype: BR! (BR0000008824325), EA! (EA000002458, EA000002460, EA000002459), K! (K000198894, K000198892, K000198895); Kwale District, Mrima hill (about halfway up road to Lungalunga from Mwambweni); 4°29'06.39'S, 39°15'47.19'E; alt. 182 m; 16 Jan. 1964.

Description.

Tree 3-27 m tall, D.B.H. 3-50 cm; young branches pubescent to glabrous, old branches glabrous; plant with lemon smell. Leaf bud ‘eragrostiform’, composed of 6-12, distichous, longitudinally folded, velutinous scales. Petiole 4-18 mm long, 1.5-5 mm wide, sparsely pubescent to glabrous. Leaf lamina 153-410 mm long, 36-127 mm wide, length:width ratio 2.3-4.3, elliptic to oblong to obovate, coriaceous, base generally acute to rounded, and minutely decurrent at the extreme base, apex generally acute to acuminate but can also appear rounded or retuse, acumen 0.5-12 mm long; surface above glabrous, surface below sparsely pubescent to glabrous when young, glabrous when old; midrib impressed above, raised below, glabrous above, sparsely pubescent to glabrous below; secondary veins 13-22 pairs, weakly brochidodromous, impressed above, raised below; tertiary veins reticulate. Inflorescences borne on trunk and branches, composed of 1-3 flowers. Flower pedicel 8-18 mm long, 3-8 mm in diameter, velutinous. Flowers bisexual, buds globose, sessile, 7-15 mm high, 9-14 mm in diameter, velutinous. Bracts 1 to 8, upper bract 3-12 mm long, 9-25 mm wide, broadly ovate, clasping the pedicel, enclosing the bud, velutinous outside, glabrous inside. Sepals 3, 8-13 mm long, 8-24 mm wide, imbricate to fused over up to ca. 30 % of their length, velutinous outside, glabrous inside, clear brown. Outer petals 3, 15-35 mm long, 13-23 mm wide, length:width ratio 1.1-2.2, broadly elliptic to elliptic, velutinous outside, glabrous inside, cream outside, cream with a dark purplish red streak from base up to 75% of the petal length inside. Inner petals 3, 15-40 mm long, 9-16 mm wide, length:width ratio 1.5-2.7, obovate, valvate at apex, velutinous outside, glabrous inside, cream to cream with a dark purplish red streak at base up to 15% of their length outside, dark purplish red with cream apex inside. Stamens 1400 to 1600, 2.5-3 mm long, 0.4-1 mm wide, anthers linear, connective prolongation truncate. Carpels 40 to 80, 3-4.5 mm long, 0.8-1.5 mm wide, pubescent, free; stigma 0.5 mm long, 0.8-1.1 mm wide, coiled, velutinous. Fruiting pedicel 10-20 mm long, 3-5 mm in diameter, velutinous. Monocarps 20 to 60, 24-90 mm long, 4.5-11 mm wide, length:width ratio 5-11, very narrowly cylindrical, torulose to torose, velutinous, greyish green; stipe 5-11 mm long, 1.5-3 mm wide, velutinous. Seeds 3-14 per monocarp, uniseriate, 3 to 9 mm long, 2-7 mm wide, ellipsoid.

Distribution.

Endemic to Somalia-Masai Region: Kenya, Mozambique and Tanzania.

Habitat and ecology.

Lowland to submontane secondary rain forests or semi-deciduous forest. Soil: coral rag or igneous intrusion. Altitude: 170-950 m a.s.l.

Phenology.

Flowers collected from January to February and from July to November. Fruits collected from January to March and from June to November.

Vernacular names.

Tanzania: ‘Mtwamu’ (Mbago 1616).

Etymology.

Although Verdcourt (1969) did not mention it in the protologue, the specific epithet might come from the Latin Uvariodendron gorgonis (derived from the Ancient Greek gorgo). This refers to the gorgons, three creatures from the Greek mythology, depicted to have hairs made of living snakes. The name of Ud. gorgonis might thus come from their fruits formed of long and numerous monocarps, resembling a gorgon’s head.

Notes.

This species differs from all other species by its fruits, unique in the genus. The fruits of Ud. gorgonis are composed of 20 to 60 monocarps, while most of the Uvariodendron species have fruits composed of 1 to 20 monocarps (except Ud. calophyllum and Ud. fuscum var. giganteum that have fruits composed of up to 35 monocarps). Moreover, the monocarps are 5 to 10 times longer than wide (vs. 1.3 to 4.5 times longer than wide in the other species). They are torulose to torose, i.e. very strongly constricted between the seeds. The ovules (and seeds) are uniseriate. The combination of these characters confers the fruits the aspect of a hairy head.

Vegetatively, this species is harder to differentiate as its leaves have dimensions that overlap with most of the other species. However, the bases of the leaves are quite peculiar: they appear generally acute to rounded but a closer look actually detects them as minutely decurrent at the extreme base. Similarly, the apices of the leaves are generally acute to acuminate, but can appear rounded to slightly retuse with a minute acumen.

The fresh leaves of Ud. gorgonis also present a citrus smell when crushed, as in Ud. angustifolium , Ud. citriodorum and Uvariopsis citrata .

Preliminary conservation status.

A previous assessment, that needs updating, listed this species as Endangered EN under criteria B2ab(iii), based on its occurrence in eight locations in Tanzania (Eastern Arc Mountains & Coastal Forests CEPF Plant Assessment Project 2009a). Here, the EOO of this species is estimated at 203,044 km2 and its AOO at 72 km2. It occurs in 11 locations in Tanzania, Kenya and Mozambique. Given its habitat is severely fragmented and there is continuing decline due to habitat loss and degradation (Eastern Arc Mountains & Coastal Forests CEPF Plant Assessment Project 2009a), it qualifies for the same previous status of Endangered EN under criteria B2ab(iii).

Additional specimens examined.

Kenya - Coast • B. Verdcourt 1890 (K) ; Kwale District, Mrima Forest, Mrima Hill ; 4°29'06.39'S, 39°15'47.19'E; 06 Sep. 1957 • B. Verdcourt 1911 (B, EA, K); Kwale District, Mrima Forest, Mrima Hill ; 4°29'06.39'S, 39°15'47.19'E; 07 Sep. 1951 • J.P.M. Brenan 14601 (EA, K, P); Kilifi District, K7, Kilifi District. Pangani ' Kaya' Forest ; 3°51'S, 39°40'30'E; alt. 170 m; 19 Nov. 1978 • R.B. Faden 70/253 (K); Kwale District, Mrima Hill, about halfway betwee Mgambweni and Lungalunga ; 4°29'S, 39°16'E; alt. 70 m; 25 Jun. 1970 • S.A. Robertson MDE78 (K); Kwale District, Mrima Hill ; 4°29'S, 39°16'E; alt. 270 m; 04 Feb. 1989 . Mozambique - Cabo Delgado • W.R.Q. Luke 9983 (MO), Quirimba NP, Ngura Inselberg ; 12°51'S, 39°39'E; alt. 420 m; 10 Dec. 2003 . Tanzania - Lindi • F.M. Mbago 2148 (K), Ruawa Forest ; 9°44'46.39'S, 39°33'04.77'E; alt. 250 m; 01 Sep. 2001 - Morogoro • A. Pócs 6061B (DSM) ; Morogoro Rural District, Kimboza Forest Reserve , between Mkuyuni and Matombo; 7°00'S, 37°48'E; alt. 300 m; 19 Nov. 1969 • A. Pócs 6280F (DSM); Morogoro Rural District, Kimboza Forest Reserve ; 7°00'S, 37°48'E; alt. 300 m; 05 Nov. 1970 • B.J. Harris 3223 (DSM, EA); Morogoro Rural District, Kimboza Forest Reserve, KFR near Matombo , Uluguru Mts ; 7°00'S, 37°48'E; 06 Sep. 1969 • C.D. Mgaza 323 (K), Luzunguru forest reserve; 6°05'S, 37°40'E; 19 Sep. 1959 • F.C. Magogo 2171 (K); Morogoro Rural District, Kimboza Forest Reserve, Kibungo Forest Reserve (Kimboza); 7°00'S, 37°48'E; alt. 600 m; 31 Aug. 1981 • F.M. Mbago 1616 (DSM); Kilombero District, Lower Kihansi Hydropower Project ; 8°24'S, 36°21'E; 30 Aug. 1997 • F.M. Mbago 1734 (K), T7: Udzungwa scarp, Upper Kihansi Gorge , forest opposite the spray zone; 8°34'54.35'S, 35°51'05.9'E; alt. 950 m; 15 Jul. 1998 • L.-P.M.J. Dagallier 47 (DSM, MPU, P, WAG); Morogoro Rural District, Kimboza forest ; 7°01'16.37'S, 37°48'17.38'E; alt. 278 m; 15 Nov. 2019 • L.-P.M.J. Dagallier 52 (DSM, K, MPU, P, WAG); Morogoro Rural District, Kimboza forest ; 7°01'18.37'S, 37°48'31.63'E; alt. 262 m; 15 Nov. 2019 • L.-P.M.J. Dagallier 57 (DSM, MPU, P, WAG); Mvomero District, Turiani village ; 6°09'36.37'S, 37°36'17.72'E; alt. 377 m; 18 Nov. 2019 • L.-P.M.J. Dagallier 61 (DSM, MPU, P, WAG); Mvomero District, Turiani village ; 6°09'46.37'S, 37°36'12.66'E; alt. 373 m; 18 Nov. 2019 • L.B. Mwasumbi 19144 (MO); Kilombero District, Kihansi gorge; 8°35'S, 35°51'50'E; alt. 800 m; 04 Sep. 1998 • R.B. Drummond 1954 (K); Morogoro Rural District, 6.4 km N of Turiani, Lusunguru Forest Reserve, near Mtibwa sawmill; 6°05'S, 37°41'E; 31 Mar. 1953 • S. Paulo 163 (EA, K); Morogoro Rural District, Kimboza Forest Reserve ; 7°00'S, 37°48'E; Nov. 1953 • S.R. Semsei 1498 (K), Mtibwa Forest Reserve ; 6°08'56.37'S, 37°50'10.32'E; Nov. 1953 • S.R. Semsei 773 (K); Morogoro Rural District, Kimboza Forest Reserve ; 7°00'S, 37°48'E; Jul. 1952 • S.R. Semsei 852 (K); Morogoro Rural District, Mtibwa Forest Reserve ; 6°07'S, 37°39'E; Aug. 1952 • T.L.P. Couvreur 69 (DSM, MO, WAG); Kilombero District, Kimboza Forest reserve, 2 km after Kimboza village , 45 km from Morogoro; 7°01'19.37'S, 37°48'16.8'E; alt. 250 m; 25 Nov. 2006 • Y.S. Abeid 2651 (EA, MO); Mvomero District, Kanga Forest Reserve, near Kwa Beku subvillage; 5°57'15'S, 37°43'11.4'E; alt. 500 m; 11 Mar. 2006 - Pwani • L.B. Mwasumbi 113377 (DSM) ; Kisarawe District, Pugu hills Forest Reserve ; 6°54'S, 39°05'E; 28 May. 2002 - Tanga • F.M. Mbago 3756 (DSM) ; Handeni District, T3: Handeni Kwansisi Mgulwi stream; 5°51'55.38'S, 38°35'39.34'E; alt. 203 m; 16 Aug. 2016 • G.A. Peter 13872 (B, K, WAG); Lushoto District, O. Usambara, Mashewa ; 4°47'S, 38°17'E; alt. 400 m; Sep. 1915 • L.-P.M.J. Dagallier 38 (BR, DSM, K, MO, MPU, P, WAG); Handeni District, Kwamsisi village ; 5°51'50.38'S, 38°35'31.77'E; alt. 196 m; 13 Nov. 2019 .

Figures

Figure 24. Uvariodendron gorgonis Verdc A habit B trunk and branches, note the young fruits all along the branches and trunk C young branches and leaves, upper side D young fruit, side view E flower, bottom view F flower, side view, inset: Coleoptera larvae frequently found in the flower. A, B no specimen associated C Dagallier 52 D, E Dagallier 38. Photos Leo-Paul Dagallier.

Figure 25. Uvariodendron gorgonis Verdc A young branch and apical ' eragrostiform' bud B flower, top view, and flower buds, side view C longitudinal section of flower bud D stamen, side view E carpel, side view F longitudinal section of carpel G fruit, side view H seed, side view. A from Verdcourt 1890 B-G from Drummond 1954 H from Verdcourt 3940 (type). Drawings by Heather Wood, from Verdcourt (1969; fig. 1, p. 514), Kew Bulletin 1969 Royal Botanic Gardens, Kew.

Figure 26. Distribution map of Uvariodendron gorgonis. Shades of grey represent elevation, from white (sea level) to darker grey (higher elevation). The inset shows the extent of the map over Africa.