Uvariodendron mbagoi Dagallier & Couvreur, 2021

Dagallier, Leo-Paul M. J., Mbago, Frank M., Luke, W. R. Quentin & Couvreur, Thomas L. P., 2021, Three new species of Uvariodendron (Annonaceae) from coastal East Africa in Kenya and Tanzania, PhytoKeys 174, pp. 107-126 : 107

Uvariodendron mbagoi Dagallier & Couvreur sp. nov. Fig. 1

Type.

Tanzania - Tanga • L.- P. M . J. Dagallier 39 (holotype: MPU ( MPU1375316 ), isotypes: DSM, K, MO, MPU ( MPU1375317 ), P, WAG); Handeni District, Kwedijela forest , ca. 8 km from Kwamsisi village ; 5°54'50.12"S, 38°36'12.35"E; alt. 156 m; 13 Nov. 2019 .

Diagnosis.

Differs from other Uvariodendron species by its stiff greyish-green leaves with slightly revolute margins, the strong bergamot scent (the citrusy smell of Citrus bergamia Risso, between lemon and orange scent) of crushed leaves and bark, its globose flower buds easily falling off and its tomentose fruits having regular tufts of higher hair density. Differs from Uvariodendron kirkii by having smaller leaves when looking at the greater leaves (157 mm maximum vs. 210 mm maximum) (Table 1 ).

Description.

Tree or shrub 3-6 m tall, 5-10 cm in diameter at breast height (d.b.h.), slash with strong bergamot smell (the citrusy smell of Citrus bergamia Risso); young branches sparsely pubescent to glabrous, old branches glabrous. Leaves distichous, simple, entire, margins slightly revolute, stiff, greyish-green. Petiole 3-6.5 mm long, 1.2-3 mm in diameter, young petiole sparsely pubescent to glabrous, old petiole glabrous. Leaf lamina 76-157 mm long, 31-59 mm wide, length:width ratio 2.2-3.5, narrowly elliptic to elliptic to narrowly obovate, between coriaceous and cartilaginous, apex acute to shortly acuminate, acumen 5-10 mm long, base acute to slightly decurrent (sometimes cuneate), above glabrous, below sparsely pubescent to glabrous when young, glabrous when old; mid rib sunken above, raised below, above glabrous when young and old, below sparsely pubescent to glabrous when young, glabrous when old; secondary veins 10-14 pairs, weakly brochidodromous, indistinct to slightly impressed above, slightly raised to raised below, inter-secondary veins absent; tertiary veins reticulate. Inflorescence borne on trunk or old branches, of 1-2 (3) flowers. Flower sessile or subsessile, pedicel 0-0.6 mm long, 2 mm in diameter. Flowers actinomorphic, hermaphroditic, buds globose 5-9 mm in diameter, velutinous, falling off very easily. Only flower buds and old fallen flowers seen. Bracts 2-5, at base of the pedicel, upper bract 5-8 mm long, 10-15 mm wide, appressed, enclosing bud, pubescent outside, glabrous inside. Sepals 3, ca. 7-8 mm long, ca. 7-12 mm wide (measures taken from bud), imbricate, enclosing the petals in bud, velutinous outside, glabrous inside. Outer petals 3, ca. 4 mm long, ca. 4 mm wide (measures taken from bud). Inner petals 3, ca. 5 mm long, ca. 5 mm wide (measures taken from bud), shortly velutinous outside, glabrous inside. Stamens more than 400, mature length unknown, anthers linear, connective truncate. Carpels 12-16, ca. 1.5 mm long, ca. 1 mm wide (measures taken from old flower), velutinous, stigma coiled. Fruiting pedicel 0-6 mm long, ca. 4 mm in diameter, pubescent. Monocarps 1-7, 20- 50 mm long, 10-12 mm wide, length:width ratio 2-4.5, cylindrical, generally curved, showing constrictions and longitudinally ridged, green-grey, tomentose with regular tufts of higher hair density, shortly stipitate, stipe 0-1.5 mm long, 5 mm wide, tomentose. Seeds 4-17 per monocarp, uniseriate to biseriate, 8-8.5 mm long, 5.5-6 mm wide, glabrous.

Habitat.

Closed evergreen forest dominated by Scorodophloeus fischeri , on coral rag soil. Altitude: 90-340 meters.

Distribution.

Endemic to Tanzania; only known from seven locations: Kimboza Forest, Msata Hill, Kwedijela forest, Kwedivikilo sacred forest, Mkwaja Ranch, Mkulumuzi river, and Hale (Fig. 2 ).

Conservation status.

This species is known from 11 records in seven locations. The current occurrence of the species in Mkulumuzi river and Hale is really unlikely given that these are now (sub)urban areas and that these records date back, respectively, more than 30 years and over a century. Changes in traditional practices and exploitation of traditionally protected forests had been observed more than 20 years ago ( Mwihomeke et al. 1998). This indicates that the current occurrence of the species in Kwedivikilo sacred forest is uncertain. Kwedijela forest is a locality under deforestation pressure with local crops slowly gaining ground (L-P. M. J. Dagallier and F. Mbago, field observations). However, the occurrences of the species in Kwedijela forest are 500 meters from the limit of Saadani National Park ( SNP), so the species is likely to occur within the SNP where the protection is strict. The only record of this species occurring within a protected area is in Kimboza Forest Reserve, which has been threatened by encroachment, logging and invasion by the exotic Cedrela odorata L. ( Hall and Rodgers 1986, Patrick 2008).

For the reasons explained above, we removed the occurrences in Mkulumuzi river and Hale from the calculations of extent of occurrence ( EOO) and the area of occupancy ( AOO). Considering the five remaining localities, the EOO is 3867 km 2 and AOO is 20 km 2. Following IUCN criterion B ( IUCN 2012), Uvariodendron mbagoi is therefore assigned a preliminary status of Endangered EN B 1ab(i,ii,iii,iv)+2ab(i,ii,iii,iv).

Vernacular names.

Zigua (or Chizigua) language: Mchenene, Msenene ( C. M. Kisena 3039), Mkenene ( T. L. P. Couvreur 3, L-P. M. J. Dagallier 39, F. Mbago 3323).

Uses.

The bark is used as a spice for meat meals and for tea.

Additional field notes.

Foodplant of Graphium kirbyi ( Papilionidae ) ( T. C. E. Congdon 532).

Etymology.

Named after Mr. Frank Mbago, curator of the Dar es-Salaam University herbarium ( DSM), to whom we owe the discovery of this species, and in honor of his botanic knowledge and fieldwork expertise in Tanzania, in particular of Annonaceae . He is also co-discoverer of the endemic Tanzanian genus Mwasumbia ( Couvreur et al. 2009) .

Paratypes.

Tanzania - Morogoro • L.- P. M. J . Dagallier 50 ( DSM, K, MO, MPU ( MPU1379109 ), P, WAG) ; Morogoro Rural District, Kimboza forest ; 7°01'18.38"S, 37°48'32.13"E; alt. 267 m; 15 Nov. 2019 . - Pwani • U . Bloesch s.n. ( WAG ( WAG.1549674; WAG.1418750), Kwedijela Coastal Forest , T3 ; 5°55'00"S, 38°36'00"E; 18 Sep. 2004. • T. L. P . Couvreur 3 ( DSM, WAG) ; Bagamoyo District, Mazizi hill, on road between Chilinze and Wami River; 6°22'14.4"S, 38°21'51"E; alt. 100 m; 09 Nov. 2006. • L.- P. M. J . Dagallier 1 ( DSM, K, MO, MPU ( MPU1379043 , MPU1379066 ), P, WAG), Msata Hill, 30 km North of Chalinze; 6°22'17.78"S, 38°21'49.97"E; alt. 317 m; 06 Nov. 2019 . - Tanga • T. C. E . Congdon 532 ( K) ; Pangani District, Mkwaja Ranch ; 5°48'50.76"S, 38°47'40.92"E; alt. 90 m; 04 Dec. 1998. • L.- P. M. J . Dagallier 40 ( DSM, K, MO, MPU ( MPU1379099 ), P, WAG) ; Handeni District, Kwedijela forest , ~ 8 km Kwamsisi village; 5°54'50.77"S, 38°36'13.27"E; alt. 155 m; 13 Nov. 2019. • W . D. Hawthorne 1420 A ( K) ; Tanga District, Mkulumuzi river, karst river valley, Steinbruch reserve ; 5°06'00"S, 39°01'00.12"E; 12 Aug. 1982. • C. M . Kisena 3039 ( MO) ; Handeni District, Collected from Kwedivikilo sacred forest near Manga Village ; 5°06'00"S, 30°37'00"E; 17 Nov. 1997. • F. M . Mbago 3323 ( DSM, K) ; Handeni District, Kwedijela forest , ~ 8 km Kwamsisi village; 5°54'50.77"S, 38°36'13.27"E; 07 Oct. 2004. • G. A . Peter 52283 ( B, WAG, K), Inseln des Pangani bei Hale; 5°17'34.8"S, 38°36'14.06"E; alt. 340 m; 31 Jan. 1915 .

Discussion.

Uvariodendron mbagoi is unique within Uvariodendron for the strong bergamot ( Citrus bergamia Risso) scent of the crushed leaves and bark. This scent is between lemon and orange scent. Other African Annonaceae species present strong scents. For example, Uvariodendron anisatum Verdcourt ( Verdcourt 1955) presents an aniseed scent, and Uvariodendron molundense (Diels) R. E.Fries var. Uvariodendron molundense citrata Le Thomas ( Le Thomas 1969) and Uvariopsis citrata Couvreur & Niangadouma ( Couvreur and Niangadouma 2016), present a lemon scent. However, no bergamot scent has been reported so far in Annonaceae .

The globose flower buds of this species easily fall off. Only flower buds were observed for this species, thus it is hard to infer the size of mature flowers. In the description above, the measures on the sepals and the petals are based on the dissection of the biggest flower bud of U. Bloesch s.n., and the carpel measurements were based on an old flower of T. C. E. Congdon 532 which has lost sepals and petals.

The fruiting specimens observed were collected from September to December. Collecting this species earlier in the year might permit the observation of flowers at anthesis.

Figures

Figure 1. Uvariodendron mbagoi A trunk with flower buds B young branch C, D entire leaf: C lower side D upper side E-H pre-anthetic flower bud: E on trunk (bottom) and fallen flower bud (top) F seen from top with sepals removed G seen from top with outer petals removed H longitudinal section; br bract, ca carpel, ip inner petal, op outer petal, se sepal, st stamen I-M Fruit: I entire with 7 monocarps J indumentum K seed L tangential cut M longitudinal cut. Photos by L. - P. M. J. Dagallier from the specimens U. Bloesch s. n. (F, G), L. - P. M. J. Dagallier 39 (B, E, H, J, L), 40 (A, C, D) and 50 (I). Scale bars: 10 mm unless stated.

Figure 2. Map of the distribution of the three new Uvariodendron species. Protected areas are represented in grey shades (see Material and Methods for details). The red cross indicates Kilulu hill, where Uvariodendron dzomboense was expected to occur but was not found.