Uvariodendron schmidtii W.R.Q. Luke, 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 schmidtii W.R.Q. Luke, Dagallier & Couvreur sp. nov. Figure 4

Type.

Kenya - Coast • W. R. Q. Luke 3087 (holotype: EA ( EA000008814 ), isotypes: K, MO, US) ; Kwale District , Shimba hills, Longomagandi; 4°14'00"S, 39°25'00"E; alt. 380 m; 20 Apr. 1992 .

Diagnosis.

This species differs from other Uvariodendron species by its flowers that are small (petals <13 mm long), velutinous, on a 10-15 mm long pedicel, with fused sepals forming a ring around the fruit pedicel, and fewer than 10 carpels. It differs from U. kirkii by its smaller petals (<13 mm versus more than 15 mm) and its sepals fused in a ring (versus free and valvate to imbricate) (Table 1 ).

Description.

Tree 10-12 m tall, d.b.h. unknown, young branches sparsely pubescent to glabrate, old branches glabrous. Leaf bud ‘eragrostiform’, composed of 5-7, ca. 10 mm long, 10 mm wide distichous, longitudinally folded, velutinous scales. Leaves distichous, simple, entire. Petiole 4.5-7 mm long, 1.5-2 mm in diameter, glabrate to sparsely puberulent. Lamina 159-188 mm long, 49-71 mm wide, length:width ratio 2.4-3.3, narrowly elliptic to elliptic, coriaceous, apex attenuate to acuminate, base acute to decurrent, above glabrous, below sparsely pubescent to glabrate when young, glabrous when old; midrib sunken above, raised below, above glabrous when young and old, below pubescent to glabrous when young, glabrous when old; secondary veins 10-14 pairs, weakly brochidodromous to brochidodromous; tertiary veins reticulate. Inflorescence borne on trunk and branches, 1-2 flowers. Flower pedicel 10-15 mm long, 2.5 mm in diameter, densely velutinous. Flowers actinomorphic, hermaphroditic, buds spherical, 6-7 mm in diameter, velutinous. Bracts 1-3, 1 at base of the pedicel, 1-2 between the 20-70% of the length of the pedicel, ca. 5 mm long, ca. 10 mm wide, velutinous outside, glabrous inside. Sepals 3, 5.5-7 mm long, 7-9 mm wide, fused on ca. 50% of the length, forming a ring around fruit pedicel, densely velutinous to velutinous outside, glabrous inside. Outer petals 3, 11- 12 mm long, 9-11 mm wide, densely velutinous to velutinous outside, glabrous inside, brown outside, cream with purple streak at base inside. Inner petals 3, ca. 10 mm long, 8-9 mm wide, connivent at apex on ca. 50% of the length, densely velutinous to velutinous outside, glabrous inside, brown-orange with margins cream and purple at base outside, cream with purple streak at base inside. Stamens more than 500, length and shape unknown. Carpels ca. 7, ca. 1.5 mm long, ca. 1 mm wide, velutinous. Stigma not seen. Fruiting pedicel ca. 16 mm long, ca. 2.5 mm in diameter, pubescent. Monocarps 3-5, ca. 32 mm long, ca. 20 mm wide, length:width ratio ca. 1.6, rounded to ellipsoid with a longitudinal ridge, sessile, sparsely pubescent, green turning orange. Seeds not seen.

Distribution.

Endemic to Kenya; only known from the Longomwagandi forest (also found spelled “Longomagandi” or “Longo-Magandi” in the literature) in the Shimba Hills National Reserve, in Kenya (Fig. 2 ).

Habitat.

Lowland forest on ridge with Antiaris , Milicia , Lovoa , Celtis , Quassia , Hymenaea , Julbernardia , Diospyros , Memecylon , and many Rubiaceae shrubs in understorey.

Conservation status.

This species is known from seven collections from a single location. Literature for the Shimba Hills forest reserve reports a surface between 0.22 km 2 ( Schmidt 1992) and 1.50 km 2 ( Cheek 2003) for Longomwagandi forest. We calculated a surface of 1.30 km 2 (see Material and methods for details). EOO and AOO are thus estimated at less than 1.50 km 2. Following IUCN criterion B, this would place the species in the "Critically Endangered CR " category. However, given that the occurrences are in the Shimba Hills National Reserve, no decline is observed or projected in EOO and AOO. The future of Uvariodendron schmidtii relies on the future of Shimba Hills National Reserve. Given that the species occurs in a single locality with a very restricted AOO (less than 20 km 2), it is "prone to the effects of human activities or stochastic events within a very short time period in an uncertain future, and is thus capable of becoming Critically Endangered or even Extinct in a very short time period" ( IUCN 2012). Following IUCN criterion D, it can be therefore assigned a preliminary status of Vulnerable VU.

Copious seedlings are found below parent trees, but few survive to maturity. Many of these “wildlings” were moved to the Base Titanium indigenous tree nursery and have been out-planted there as part of their mine rehabilitation program.

Vernacular name.

Mbebeneka in Kidigo language ( R. Schmidt 788).

Etymology.

This species is named after Robert Schmidt, a PhD student studying the ecology of the Shimba Hills National Reserve who first collected it in September 1988 and brought it to the attention of W. R. Q. Luke.

Paratypes.

Kenya - Coast • W. R. Q. Luke & S. A. Robertson 2737 ( EA, K, MO, US); Kwale District, Shimba hills, Longomagandi; 4°14'00"S, 39°25'00"E; alt. 390 m; 18 Mar. 1991 . • W. R. Q. Luke 2919 ( EA ( EA000008817 ), K, MO, US); Kwale District , Shimba hills, Longomagandi; 4°14'00"S, 39°25'00"E; alt. 390 m; 15 Oct. 1991 . • W. R. Q. Luke 4717 ( P ( P02084012 ), Ukunda ); Kwale District , Shimba hills, Longomwagandi; 4°14'00"S, 39°25'00"E; alt. 380 m; 12 Sep. 1997 . • W. R. Q. Luke 11676 ( EA, K, MO, US); Kwale District , Shimba hills, Longomagandi; 4°14'00"S, 39°25'00"E; alt. 380 m; 30 Dec. 2006 . • S. A. Robertson 7556 ( EA, K, WAG ( WAG0129164 )); Kwale District , Shimba Hills, Longomagandi; 4°14'00"S, 39°25'00"E; alt. 450 m; 04 Jun. 2005 . • R. Schmidt 788 ( EA); Kwale District, Shimba Hills, Longomagandi; 07 Sep. 1988 .

Discussion.

This species shows ‘eragrostiform’ leaf-buds, a feature described in Uvariodendron gorgonis Verdcourt ( Verdcourt 1969) and Uvariodendron dzomboense Dagallier, W. R. Q. Luke & Couvreur (this publication). This structure is composed of several (5-7 in U. schmidtii and U. dzomboense , 6-12 in U. gorgonis ) distichous and densely pubescent scales that might be a protection for the apical meristem against drought or herbivores. The adjective ‘eragrostiform’ refers to the genus Eragrostis ( Poaceae ) that has a peculiar form of flattened spikelet composed of compact and clustered florets. Even though this feature is striking, it seems hard to use it as a diagnostic character. Similar apical buds are also found in other Annonaceae species such as Monodora minor Engler & Diels ( Couvreur 2009) or in Uvariodendron usambarense Fries and Uvariodendron giganteum (Engler) Fries.

Figures

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.

Figure 4. Uvariodendron schmidtii A young branch with leaves B eragrostiform axillary bud C detached monocarps and pedicels D two-flowered inflorescence E flower, apical view. br bract, ca carpel, flp flower pedicel, frp fruit pedicel, ip inner petal, mo monocarp, op outer petal, se sepals ring, sts stamen scars. Photos by L. - P. M. J. Dagallier from the specimens W. R. Q. Luke 3087 (C) and W. R. Q Luke 4717 (A, B), and by W. R. Q. Luke from a living individual (D, E). Scale bars: 10 mm unless stated.