Salacia nigra Cheek, 2014

Gosline, G. & Cheek, M., 2014, Two new African species of Salacia Salacioideae, Celastraceae, Blumea 59 (1), pp. 26-32 : 29-31

Salacia nigra Cheek , sp. nov. — Fig. 2d , 3 ; Map 1

Salacia sp. A Keay (1958) 1, 2: 632.

Salacia sp. nov. “SALS” Thomas et al. (2003) 34.

Salacia loloensis Loes.var. sibangana sensu Gosline,van der Burgt & Cheek (2004) 134 non Hallé.

Salacia sp. nov. 1 Cable & Cheek (1998) xlvii & 30.

Similar to Salacia mayumbensis Exell & Mendonça but being a larger tree (to 15 m), having larger leaves (to 40 cm rather than 25 cm) with no or indistinct marginal teeth, dark purple rather than yellow flowers, no radial striations on the disk and larger fruits. — Type: Groves , M. 265 (holo YA; iso BR, K, SCA, WAG), Cameroon, South West Province , Mabeta-Moliwe , Dikulu Village [N4°05' E9°16'], alt. 30 m, trail along seashore to west of Dikulu Village, 9 March 1995 .

Etymology. nigra (black) the petals are almost black in colour: ‘black flower’.

Shrub or tree 2–5(–15) m tall, glabrous, without resin. Bark dark brown or grey, smooth, outer slash pink to orange, inner cream; branching decussate with flattened sprays of leaves. Young shoots terete to slightly flattened at nodes, ferruginous, smooth with fine striation, older twigs with grey sometimes gnarled bark. Leaves simple, opposite; petiole 0.7–1.7 cm long, often deeply striate and drying darker than both stem and midrib; blade coriaceous to subcoriaceous, 23–43 by 6–16 cm, narrowly elliptic to oblong, acumen 0.8–1.5 cm long, base rounded to obtuse; 16– 22 pairs of secondary nerves looping 3–5 mm from the margin, whitish above, yellow or brown and very prominent beneath; margin slightly crenulate or sparingly serrate and revolute when dry. Inflorescence ramiflorous, fascicles of up to 8 flowers, glabrous; bracts triangular, 10.5 mm wide by 0.5–0.75 mm long; pedicels 1.1–1.4 cm long at anthesis. Buds globular to oblate, (1.5–)2.0– 2.5 mm long. Flowers purple to purple-brown drying almost black, 4 –6 mm diam; calyx 3.0– 4.5 mm diam, sepals green to light orangebrown, highly unequal, the largest often twice the width of the smallest, elliptic, 1.0–3.0 by 0.75–1.5 mm, entire, free; petals semicircular to broadly obovate, imbricate, 3.0–4.5 by 2.0–3.0 mm, margin entire. Disk shallowly cupular, 1.7–2.5 mm diam, 0.2 mm thick, often white contrasting strongly with the black petals. Stamens with flattened filaments inserted on the inner wall of the cupular disc, 1.5 mm long, anther cells confluent, forming an obtuse angle. Ovary 3-lobed, 1.0– 1.25 mm diam tapering to style 1.0– 1.5 mm long, stigma punctiform, ovules 2 per locule, superposed. Fruits pyriform to narrowly ellipsoid often gibbous, 50–75 mm long when dried (100 by 35 mm in vivo, Cheek 3453) with blunt rostrum 10–15 mm long, orange to orange-red, waxy, warty and irregularly ridged exterior, fruiting pedicel 1.1–2.1 by 0.2 cm; (1–)2–3 white seeds surrounded by a translucent, gelatinous pulp.

Distribution & Ecology — High rainfall coastal areas of Cameroon and Nigeria. Disturbed, semi-disturbed or intact ever- green forest, 30–330 m altitude.

In the Ebo forest a species of mosquito was observed visiting several flowers of S. nigra in turn over five minutes, spending 5 –10 seconds at each possibly to imbibe nectar and potentially effecting cross-pollination (Cheek pers. obs. 2006). The fruits are eaten by gorillas in the Campo Reserve (Webb & Bullock 654).

Representative specimens. CAMEROON, Centre Region,Ndanan 2,Ndanan 1 to Ndanan 2 forest to left of trail, Darbyshire 301 (K, WAG, YA), 30 Mar. 2004; Littoral Region,Ebo Proposed National Park Njuma Research Station (nearest village Ndokbagengue), Xanthos 230 (K), 26 May 2010; Xanthos 140 (K), 1Apr.2010;Ebo Proposed National Park Bekob, Tchiengue 2450 (K, YA), 14 Feb.2006; Tchiengue 2532 (K,YA), 17 Feb. 2006; Southwest Region, Moliwe Makota River watershed, TD Watts 249 (K, SCA, YA), 29 Apr. 1992; Mabeta-Moliwe Reserve, Southern base line, Sunderland 1145 (K, SCA, YA), 24 Mar. 1992; Mabeta-Moliwe Reserve, Southern base line, c. 700 m, Cheek 3453 (K, SCA, YA), 2 July 1992; Bimbia 4 km SE Limbe (TB), Baker 277 (K, SCA,YA), 5 Aug. 1993; Dikulu, Mangrove stream between road and mangroves at top of beach, Cable 1370 (K, SCA,YA), 26 Feb. 1995;Liwenyi Forest around the Likenge village, Tchouto 516 (K, SCA,YA), 18 Mar.1993; Limbe Patch of high forest close to coast near Victoria, Brenan 9590 (K), 6 Apr. 1948;Boa Mokoko Forest Reserve,Ekombe-Mofako, Pouakouyou 82 (K, SCA), 4 June 1994; Mokoko, Thomas 10014 (K, SCA,YA), 20 May 1994; Bera Northern Korup F.R., Olorunfemi FHI 30665 (K), 3 July 1951. – NIGERIA, Edo state, Iyekoriowon District, Usonigbe Forest Reserve, Daramola FHI 72333 (FHI, K, MO), 5 Oct. 1973.

f

cm

5

;

marbled often

,

cm

smooth

3

;

length 6 cm;,

marbled

maximum smooth, turbinate to

smooth

,

;

Fruit

obovoid obovoid orange

globular

Flowers pink to yellow

purple

Acumen triangular ligulate margin revolute,

acuminate

triangular

Leaf entire entire secondary

serrulate

8

–

5 10

– Pairs nerves 4 9

–

6

,

10

cm

oblanceolate

–

4 to cm

by

cm

5

–

–

22 elliptic 5 7 –

3

by

. species Leaf size elliptic 8, narrowly 10 by – 20 Salacia height non-lianescent Maximum m 5 4 m of lehmbachii Characters. var loloensis . var 1 Table Taxon lehmbachii loloensis S.. S cm

7

; smooth

, fusiform

?

yellow ligulate toothed strongly not but undulate

16

– 14

, oblanceolate to cm elliptic 10 – 6

by narrowly – 30 15

12

–

8

?

m

m

2

3

sibangana

.

var loloensis

pallescens

.

.

S cm 3; smooth, ovoid yellow entire

7 – 5

cm 7 – 5 by 20 – 8, elliptic

m 3

mannii . S verrucose, variable orange to yellow ligulate toothed weakly to serrulate

13 – 11

cm 7 – 4 by 25 – 10, elliptic narrowly

m 3

mayumbensis . S unknown purple to red caudate serrulate to toothed weakly

15 – 13

cm 7 – 4 by 22 – 14, lanceolate

m 3

ndakala . S cm 10 – 8; warty, gibbous, ellipsoid to pyriform purple dark ligulate toothed weakly to entire

20 – 12

cm 15 – 6 by 40 – 18, oblanceolate

m) 15 – (5

nigra . S

Conservation assessment — Vulnerable (VU B2a,b(iii)) ( IUCN 2012). The previous assessment of Critically Endangered given in Cable & Cheek (1998: xlvii) and referred to in Onana & Cheek (2011: 113) is lowered based on additional locations for the species. Eight distinct locations are indicated on Map 1 with an AOO of 80 km 2 using the 4 km 2 cell sizes advised by IUCN (2012). While S. nigra has secure populations in the Korup National Park and the proposed Ebo National Park, threats exist at all other locations. Usonigbe Forest Reserve viewed on Google Earth (imagery from 2008) is now 90 % agricultural fields and S. nigra is very probably extinct at this single known location in Nigeria. Slash-and-burn agriculture inside the Mefou National Park, very close to Yaounde, was recorded in 2004 ( Cheek et al. 2011). At both the type location and the Campo Ma’an National Park and Technical Operations Unit illegal logging, iron ore mining and oil-palm plantation development are threats. The specimen location from Campo Ma’an lies outside the gazetted national park where logging concessions exist. Most of the specimen records of the species are from the eastern (Bimbia-Bonadikombo Community Forest, formerly Mabeta-Moliwe) and western (Mokoko-Onge) foothills of Mt Cameroon. The forest present at Bimbia-Bonadikombo has been extensively impacted by slash-and-burn agriculture since collections were made in the early 1990s ( Cheek 1992). In the forest of the western foothills at Mokoko agriculture including oil-palm and petroleum exploration are current threats.

Notes — Salacia nigra is one of a group of closely related shrubs to small trees in Hallé’s group 3 of Flore du Gabon (1987). This taxon was named as Salacia sp. A in The Flora of West Tropical Africa based on Brenan & Jones 9590; but Hallé subsequently identified this and other specimens as S. loloensis Loes. var. sibangana Hallé. Examination of specimens of S. loloensis var. sibangana shows a similarity in the large leaves, but the fruits to be smooth rather than warty, the flowers yellow rather than purple and the leaves smaller. (The similarity of the fruits in S. loloensis var. loloensis and var. sibangana support Hallé’s association of the two taxa.) Salacia nigra fruits appear close to S. mayumbensis in this group of species, and we use this as the ‘similar to’ species in the diagnosis. Salacia ndakala R.Wilczek from Kivu is closely related to S. mayumbensis ; no fruits are known from this species but it is likely to have the same warty fruit type.

A number of specimens in southern Cameroon do not fit neatly with the character matrix and may represent additional new taxa or regional variations. De Wilde 2076 from south of Ebolowa is determined by Hallé as S. mayumbensis but is more weakly toothed than Gabonese specimens. Webb & Bullock 654 from the Campo Reserve is similar. Darbyshire 301 from near Yaoundé is also weakly toothed with larger leaves (30 cm long) and 14 secondary nerve pairs.

The listing in Tchoutou (2004: 152) of S. loloensis var. sibangana in the Campo Ma’an refers to a small woody climber and is probably a misidentification. We have not seen the collections on which the record is based.

The Smithsonian 50-ha plot in the Korup National Park inven- tories 564 individuals of what is undoubtedly this species (but with only 11 individuals with stems over 2 cm diam). Ranking 99th in frequency of occurrence in the list of species by number of individuals ( Thomas et al. 2003)

Table 1 summarizes the taxa of true trees and small shrubs related to S. loloensis . Salacia lehmbachii Loes. (represented by S. lehmbachii var. lehmbachii ), S. pallescens Oliv. and S. mannii Oliv. are quite different in aspect from the other species but are included here for completeness.

We also give a key to all the non-lianescent species of central and west African Salacias. It is hoped this will be of use, but care is necessary in that many (most?) of the lianescent species begin life as small sarmentous shrubs.

Figures

Map 1 Distribution of Salacia arenicola Gosline (▲), S. nigra Cheek (■) and S. mayumbensis Exell & Mendonça (●).

Fig. 2 a–c: Salacia arenicola Gosline. a. Habit; b. fruits; c. flowers and stem showing lenticels. — d: Salacia nigra Cheek. Fruiting specimen. — Photos by: a, c: G. Gosline; b: M. Cheek.

Fig. 3 Salacia nigra Cheek. a. Flowering habit; a1. bud; b. flower; c. calyx; d. longitudinal section of flower; e. transverse section of ovary; f. stamen; g. fruit- ing branch; h. longitudinal section of fruit (a, a1: F Watts 249; b–e: Sunderland 1145; g, h; Cheek 3453). — Scale bars: a, h = 5 cm; d–g = 1 mm; a1, b, c = 2 mm. — Drawn by Susanna Stewart.