Empogona jenniferae Cheek, 2018

Empogona jenniferae Cheek View in CoL , sp. nov. — Fig. 1 View Fig

Differing from E. congesta (Oliv.) Cheek in the number of secondary nerves on each side of the midrib 4–6(–7) (not (5–)7–10(–12)); corolla tube and lobes both 5–6(–7) mm long (not 2–4(–5) mm and 4.5–5 mm,respectively); fruit ellipsoid, 7 by 6–8 mm, disc exserted, conspicuous (not globose, 5 mm diam,disc concealed). — Type: Wursten 1070 (holo K;iso BR n.v., LMA n.v.), Mozambique, Manica, slopes of ‘Mt Chimanimani’,western side Mevumodzi Valley, Eastern Chimanimani Mts, S 19°47'51" E33°07'21", fl. 30 Oct. 2014.

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Etymology. Named in memory of Jennifer Ward Oppenheimer who was a philanthropist, committed conservationist and supporter of Kew’s Tropical Important Plant Areas work in Mozambique.

Erect tree 3 m tall, bark finely fissured, slash lime ( Müller 728). Internodes terete, (0.5–) 2–3 cm long, (1–)1.8–2.5(–3) mm diam, pale brown, minutely and sparsely puberulent, hairs simple, patent, 0.1 mm long. Leaves opposite and equal at each node, glossy and leathery, green yellow, elliptic, rarely rhombic-ovate, (3.2–)3.6–5.6(–6.3) by (1.4–)1.9–2.5(–3.5) cm, apex with a short, broad, round-apexed acumen 2–4(–6) mm long, rarely the apex not acuminate but rounded, base asymmetric, acute to obtuse, often decurrent as narrower wings of the petiole; secondary nerves 4–6(–7) on each side of the midrib, arising at c. 50° from the midrib, strongly brochidodro- mous, uniting to form a looping marginal nerve 1–2 mm from the margin, distalmost secondary nerves reflexing towards the more proximal nerves; tertiary nerves conspicuous on both surfaces, forming a coarse reticulum, also forming an intramarginal nerve < 0.1 mm from the margin, connected with the thicker secondary marginal nerve by numerous radiating tertiary veins. Domatia absent. Margin reflexed. Petiole canaliculate, (1–)2–4(–5) mm long, margin narrowly winged, glabrous. Stipules free, not sheathing but margins united with petiole bases, forming a pocket c. 2 by 2.5 mm, apex aristate, aristae 3–4 mm long, inner surface with simple hairs 0.3–0.8 mm long, abaxial surface with fine transverse lines, sparsely puberulent as stem. Inflorescences axillary, opposite, in up to 4 successive nodes below the stem apex, 1–4-flowered, c. 1.5 cm long, peduncle 1–1.5 mm long; cymose, calyculate, minutely, sparsely and inconspicuously patent-puberulent, at stem; calyculi cupular, or with minute and obscure stipular and foliar lobes, subtending each flower pair, flowers sessile, subtended by a cup-shaped calyculus, 1.1–1.8 by 2 mm, inner surface with simple hairs 0.3–0.5 mm long, outer surface glabrous or with a few patent hairs as stem. Calyx-hypanthium, subcylindric, 1.3–1.7 by 2 mm, base concealed by calyculus; calyx limb-tube short c. 0.1–0.2 mm; calyx lobes (4 or) 5, quadrate or hemi-orbicular 0.6–0.8 by 0.8–0.9 mm, not touching at anthesis, glabrous on both surfaces or with 1–3 hairs near the margin on the inner surface, the margin with 7–9 patent fimbriae 0.05–0.13 mm long. Corolla in pre-anthetic bud narrowly ovoid c. 8 by 4 mm, lobes overlapping to left; at anthesis white, tube dilating, 5 mm long, 2 mm wide at base, 4 mm at apex, lobes (4 or) 5 reflexed, about as long as tube, ovate-oblong 5–6(–7) by 3(–3.5) mm, apex shallowly retuse, with 5–10 patent minute hairs 0.1 mm long, otherwise glabrous. Inner surface glabrous, except for five densely hairy patches alternating with and inserted 0.5 mm below the attachment of the staminal filaments, patches 1–1.5 mm diam at base, hairs 1–1.5 mm long, radiating from patch, rigid. Stamens (4 or) 5, exserted, introrse, inserted 0.5–1 mm below the mouth of the corolla tube; filaments 2.5–3 by 0.6 mm, anthers narrowly oblong 4.5–5.5 by 0.6–1 mm, apex with connective extended apically beyond the thecae, triangular, 0.5–0.7 by 0.4 mm, filament insertion between basi- and medi-fixed. Disc glabrous, shortly cylindric, 0.4–0.5 by 1.2 mm, the upper surface flat, sunken around style base, the sides vertical, with shallow flanges ( Fig. 1j View Fig ). Style glabrous, cylindric, 0.3–0.5 mm diam, apex dilated, 0.75 mm wide, bifurcate, the two arms with stigmatic surface appressed together, exserted with stamens, c. 2.5 mm long. Ovary 2-celled, ovules numerous. Fruit ripening black, ellipsoid, c. 7 by 6 mm, apex with disc accrescent, slight exserted beyond the persistent calyx lobes. Seeds numerous, triangular in side view, with adaxial excava- tion, c. 2–2.5 by 2–2.5 mm, outer surface with epidermal cells, hardened, black, convex.

Distribution & Ecology — Zimbabwe and Mozambique;known only from submontane forest and cliff, quartzitic sandstone substrate, Chimanimani Mt, 1200 –1580 m altitude.

Additional material. ZIMBABWE, Müller 728 ( K, SRGH), The Corner , Martin Forest Reserve , Melsetter [Chimanimani] District, fl. buds, 15 Nov. 1967 ; Cronwright 4026 ( BR n.v., K), Chimanimani Mts , fr., 23 May 1923 .

Conservation — Since the Cronwright specimen only gives ‘Mt Chimanimani’, the location cannot be pinpointed. We are left with the Müller specimen and that of Wursten giving us two precise sites one on each side of the border. Nothing in the data labels suggests that more than one individual was seen by each collector. Wursten specifies ‘ One specimen seen only’. Therefore the evidence points to E. jenniferae as occurring as widely scattered single individuals. It is not common even within its small range.

A mission to gather populational data and an understanding of threats on the endemic plant species of Chimanimani in 2015 did not refind this species ( Timberlake et al. 2016). In contrast, another narrowly endemic coffeoid woody plant, Sericanthe sp. B of Flora Zambesiaca, was found in more than ten sites on that survey. Ongoing artisanal mining for gold in the upland quartzitic areas was and may continue to be a threat for tree species such as E. jenniferae since the miners used the sparse locally available trees and shrubs for fuel and shelter construction ( Timberlake et al. 2016).

Under Criterion B we assess E. jenniferae as EN B1+B2ab(iii) in view of the stated threat, and since two management based locations are known (one in Zimbabwe, the other in Mozambique) equating to an area of occupancy of 8 km 2 using IUCNprefixed 4 km 2 cell size. The extent of occurrence is estimated as equal to the area of occupancy.

Under Criterion D we assess E. jenniferae as Critically Endangered, since despite numerous missions surveying the plant of the upper quartzitic slopes of Chimanimani by numerous botanists, including all three of the authors of this paper, only three individuals have been recorded. We estimate that the total number of mature individuals is greater than this, but that it is less than 50.

Cultivation. This species has potential for ornamental horticul- ture if it can be cultivated in view of its attractive glossy leaves and abundant, relatively large, likely sweet-smelling flowers.

Müller 728 had been initially determined as Tricalysia congesta , and Cronwright 4026 as T. cacondensis . Both had been redetermined as T. ruandensis Bremek. by Robbrecht in 1978 in the course of his revision of Tricalysia .