Five new species of Englerophytum K. Krause (Sapotaceae) from central Africa Author Gautier, Laurent Author Lachenaud, Olivier Author Burgt, Xander van der Author Kenfack, David text Candollea 2016 2016-10-11 71 2 287 305 journal article 2939 10.15553/c2016v712a14 dce64c93-3c8e-41c7-a2af-9e57afb600f6 2235-3658 5756571 Englerophytum ferrugineum L. Gaut. & O. Lachenaud , spec. nova ( Fig. 3 , 9 ). Typus : GABON . Prov. Estuaire: Mts de Cristal , Route de Kinguélé , 18.I .1968 , fl., Hallé & Villiers 4506 bis ( holo- : P [ P00099668 ]!). Englerophytum ferrugineum L. Gaut. & O. Lachenaud differs from other members of the genus by the combination of large oblanceolate leaves (15.5-)23-70 X (4.2-) 6-15 cm with dark ferruginous-brown underside, many-flowered inflorescences borne on the trunk, short flowering pedicels ( 3-6 mm ) and stamens with f ilaments fused into a tube and connivent anthers. The leaf colour and indumentum resembles Zeyherella letestui Aubrév. & Pellegr., but that species has free stamen filaments, inflorescences with few flowers (10-20) on longer pedicels ( 8-10 mm ) and borne on the leafy twigs (not on the trunk), and rather small leaves, not exceeding 17 X 5 cm . A medium-sized tree, 20 m high and 40 cm DBH, with white latex; twigs 8 mm in diameter, densely appressedpubescent with dark brown indumentum. Stipules paired, falciform with inrolled margins, not keeled, 8-15 mm long X 2-4 mm broad, appressed-pubescent with ferrugineous-brown indumentum outside, glabrous inside, persistent or caducous. Leaves alternate, simple, obovate to oblanceolate; petiole 20- 30 mm long, 5-7 mm in diameter, longitudinally ribbed when dry, with a persistent dense appressed ferrugineous-brown pubescence; blade (15.5-) 23-70 cm long, (4.2-) 6-15 cm broad, broadest at 2/3 of its length, acute to obtuse at base, rounded to shortly acuminate at apex (acumen up to 1 cm ), chartaceous and strongly discolorous; upper side green, glabrous except for very scattered 0.4-1.2 mm medifixed trichomes; lower side dark ferruginous-brown, with a dense immersed white indumentum mostly hidden by an additional dense external layer of adpressed ferruginous 0.3-1.0 mm trichomes; primary nerve in continuity of the petiole, canaliculate above, very prominent below, appressed brownish-pubescent; nervation brochidodromous, with 40-00 secondaries c. 10 mm apart, interspersed with parallel inter-secondaries and tertiaries, indistinctly raised above and shallowly raised below, forming an angle of 70-80° with the primary nerve, then finally curving and anastomosing 2 mm from the margin. Inflorescences on the trunk, fasciculate, with 100-200 very densely aggregated flowers; pedicels 3-6 mm long and 0.6 (proximal)-1.0 (distal) mm wide at anthesis, shortly appressed brown-pubescent. Calyx ferrugineous-brown, consisting of 5 sepals shortly united at base, the lobes imbricate, 3 mm long X 3.5 mm broad, obtuse at apex, very shortly appressed pubescent outside (the outer sepals entirely brown-pubescent, the inner ones with golden trichomes and a 0.3 mm glabrous area inside the ciliate margin), glabrous inside. Corolla (colour unknown) glabrous, spherical, 4-5 mm in diameter; tube cupshaped, very short, 0.5-1 mm long; lobes 5, broadly ovate to semi-circular with rounded apex, imbricate, 4 X 4 mm . Stamens 5, opposite the corolla lobes; filaments connate into a cylindrical tube 2.3 mm long, attached to and in continuation of the corolla tube and concealing the ovary; anthers connivent and closing the corolla throat (possibly splitting at a later stage of flower development), broadly sagittate, 3 mm long X 1.5 mm broad, shortly apiculate, extrorse and dehiscing longitudinally. Ovary conical, 1.0 mm high and 1.0 mm diameter at base, with 5 locules and one ovule per locule, densely hirsute with stiff 1.9 mm long trichomes directed upwards; style glabrous, 2 mm long, 0.6 mm in diameter at base, tapering to 0.3 mm at the blunt apex. Fruits unknown. Fig. 9. – Englerophytum ferrugineum L. Gaut. & O. Lachenaud. A. Inflorescence ; B. Flower bud; C. Longitudinal section of flower; D. Longitudinal section of corolla; E. Leaf blade detail, upper surface; F. Leaf blade detail, lower surface; G. Branch apex showing stipules; H. Extremity of twig with leaves. [Drawing: G.Loza] Etymology . – The specific epthet refers to the ferruginousbrown colour of the lower leaf surface, twigs, pedicels and calyx. Distribution and Ecology . – Englerophytum ferrugineum is endemic to the Crystal Mountains in north-western Gabon . It grows in primary forest on drained soils, or sometimes along rivers, 500-600 m in altitude. Conservation status . – Englerophytum ferrugineum is known from three locations, representing an EOO and AOO of respectively 79 and 12 km ², and all situated outside protected areas. The species has a narrow range and deforestation for mining and/or agriculture represents a potential threat. A decline in EOO, AOO, habitat extent and quality, number of subpopulations and number of individuals is expected. It is preliminarily assessed here as “Endangered” [EN B1ab(i,ii,iii,iv,v)+B2ab (i,ii,iii,iv,v)]. Notes . - The type collection of E. ferrugineum (Hallé & Villiers 4506 bis) only consists of inflorescences collected on the trunk of a medium-sized tree 20 m high, whose foliage was probably out of reach of the collectors. The description of the vegetative parts is based on the paratype Hallé & Villiers 4506 , collected on the same day by the same collectors in the same locality, on a smaller tree 7 m high. The collectors were confident that the two collections were conspecific, as the label of N° 4506 says: “Fleurs voir 4506 bis”. Since they were experienced botanists and the species has a very distinctive foliage, we have no reason to question this association. Vegetatively, this species resembles Zeyherella letestui Aubrév. & Pellegr., which has the same dark brown indumentum on the lower side of the leaves. The latter, however, differs in the free stamen filaments, the inflorescences with few flowers (10-20) on longer pedicels ( 8-10 mm ) and borne on the leafy twigs (not on the trunk), and the rather small leaves, not exceeding 17 X 5 cm . The leaves of Englerophytum ferrugineum are much larger, except sometimes at the very apex of the twigs. A collection from southern Cameroon , Letouzey 9221 (P), and another from Monts de Cristal in Gabon , MBG Transect 1025 (BRLU), have leaves resembling this species, but not so densely dark brown pubescent beneath, and with non-appressed T-shaped hairs. They probably represent an undescribed related species; unfortunately, both collections are sterile. Paratypi . – GABON . Estuaire . Mts de Cristal , route de Kinguélé , 18.I .1968 , ster., Hallé & Villiers 4506 ( P [2 sheets]); Mts de Cristal , Mt Mbilan , 0°28’18”N 10°15’24”E , 2005 , ster., MBG Transect 443 ( BRLU ); Mts de Cristal , montagnes de Mvé Lakéné , 0°34’0”N 10°11’57”E , 2007 , ster., MBG Transect 762 ( BRLU ); Mts de Cristal , route en venant à Mela , s.d., ster., Normand 1 ( P ).