KEW BULLETIN (2016) 71:55 DOI 10.1007/S12225-016-9673-2 ISSN: 0075-5974 (print) ISSN: 1874-933X (electronic) Inversodicraea Engl. resurrected and I. pepehabai sp. nov. (Podostemaceae), a submontane forest species from the Republic of Guinea Martin Cheek1 & Pepe Haba2,3 Summary. Inversodicraea, shown by previous workers to merit resurrection, is restored here, to include all those species previously included in Ledermanniella subg. Phyllosma. The final seven species remaining in subg. Phyllosma are formally transferred to Inversodicraea as I. mortonii, I. gabonensis, I. boumiensis, I. harrisii, I. paulsitae, I. torrei and I. thollonii. A new species from the submontane forest of Mt Ziama, in Guinea-Conakry is formally described as I. pepehabai. Similar to I. adamesii, it is assessed as Endangered according to the IUCN 2012 standard. Key Words. Conservation, forest, Ledermanniella, rheophyte, Ziama. Introduction Podostemaceae are a pantropical family of annual or perennial herbs. All species of the family are restricted to rocks in rapids and waterfalls of clear-water rivers, and are therefore rheophytes. However this very habitat is being increasingly exploited for hydropower at some risk to the survival of the Podostemaceae they contain (Schenk et al. 2015; Cheek et al. 2015; Cheek & Ameka 2016). Most of the African species of Podostemaceae are narrow endemics, many being species known from only a single waterfall. New discoveries of species are still being made frequently (Rial 2002; Cheek 2003; Schenk & Thomas 2004; Beentje 2005; Kita et al. 2008; Schenk et al. 2015; Cheek et al. 2015; Cheek & Ameka 2016). Important characters in defining genera in Podostemaceae are the position of the flower in the unruptured spathellum, and the shape, and sculpture of the ovary. At species level, important characters are the shape and relative proportions of spathellae, stigmas, anthers, filaments, gynophores, pedicels, and leaves. The current generic classification of African Podostemaceae is based on the framework established by Cusset (1973, 1974, 1978, 1983, 1987). This work has been compiled and updated by Rutishauser (2004). Recently, combined morphological and molecular phylogenetic studies of African Podostemaceae have shown that Ledermanniella (as delimited by Cusset) is paraphyletic, including all other sampled genera of Podostemaceae recognised in Africa (Thiv et al. 2009, employing plastid markers matK, trnD-trnT, rpoB-trnC in sampling 9 genera and 17 species of African Podostemaceae, and Schenk et al. (2015), employing plastid markers matK, trnL, rpoB-trnC, ndhF, rbcL and matR in sampling 10 genera and 27 species of African Podostemaceae). Materials & Methods Nomenclatural changes were made according to the Code (McNeil et al. 2012). Herbarium material was examined with a Leica Wild M8 dissecting binocular microscope fitted with an eyepiece graticule measuring in units of 0.025 mm at maximum magnification. The drawing was made with the same equipment with a Leica 308700 camera lucida attachment. The format of the description follows Cusset (1983), e.g in referring to scale-like leaves as “leaflets” and long, subfiliform, to narrowly ribbon-like dichotomously branched leaves as “leaves”. All specimens marked “!” have been seen. The conservation assessment follows the IUCN (2012) standard. The main online search address used for retrieving specimen data from P was https://science.mnhn.fr/institution/mnhn/collection/p/item/p00179355?listIndex= 128&listCount=610. Herbarium codes follow Index Herbariorum (Thiers, continuously updated). Accepted for publication 9 November 2016. 1 Herbarium, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AE, UK. e-mail: m.cheek@kew.org 2 Herbier National de Guineé, Université de Gamal Abdel Nasser, BP 680, Conakry, République de Guinée. 3 Guinée-Biodiversité., Conakry, République de Guinée. © The Board of Trustees of the Royal Botanic Gardens, Kew, 2016 55 Page 2 of 8 Completing the resurrection of Inversodicraea Engl. Molecular phylogenetic sampling of African Podostemaceae has been only c. 30% complete at species level (Schenk et al. 2015). Thiv et al. (2009) and Schenk et al. (2015), have convincingly shown that Ledermanniella subg. Phyllosma C. Cusset forms a well-supported clade of species that are sister to the rest of all other African Podostemaceae sampled, mainly comprising Ledermanniella subg. Ledermanniella and, embedded within it, seven smaller genera: Macropodiella, Winklerella, Djinga, Dicraeanthus, Leiothylax, Letestuella and Stonesia. Thiv et al. (2009) and Schenk et al. (2015) both advocate resurrecting the generic name Inversodicraea Engl., as the oldest generic name for the species of Ledermanniella subg. Phyllosma and both transfer species formerly included under the last taxon to Inversodicraea. The last seven remaining species names of subg. Phyllosma are placed into Inversodicraea below. Species of the resurrected Inversodicraea (Ledermanniella subg. Phyllosma as erected, delimited and revised by Cusset (1983)) are easily recognised due to the unique synapomorphy (derived feature) in having their stems more or less densely covered in spirally inserted, dorsiventrally flattened, often lobed, rarely needle-like, scale-leaves or “leaflets”, often in addition to larger, but caducous, branched, filiform leaves which are also commonly seen in other African Podostemaceae. Such scale-leaves are otherwise absent in African Podostemaceae. 1. Inversodicraea mortonii (C. Cusset) Cheek comb. nov. http://www.ipni.org/urn:lsid:ipni.org:names:60472989-2 Basionym: Ledermanniella mortonii C. Cusset, Bull. Mus. Natl. Hist. Nat. 4e sér., 5, B, Adansonia 4: 368 (1983). Type: Sierra Leone, Morton SL 2899 (holotype WAG; isotype K!). 2. Inversodicraea gabonensis (C. Cusset) Cheek comb. nov. http://www.ipni.org/urn:lsid:ipni.org:names:60472990-2 Basionym: Ledermanniella gabonensis C. Cusset, Bull. Mus. Natl. Hist. Nat. 4e sér., 5, B, Adansonia 4: 368 (1983). Type: Gabon, Le Testu 6017 (holotype P). © The Board of Trustees of the Royal Botanic Gardens, Kew, 2016 KEW BULLETIN (2016) 71:55 3. Inversodicraea boumiensis (C. Cusset) Cheek comb. nov. http://www.ipni.org/urn:lsid:ipni.org:names:60472991-2 Basionym: Ledermanniella boumiensis C. Cusset, Bull. Mus. Natl. Hist. Nat. 4e sér., 5, B, Adansonia 4: 370 (1983). Type: Gabon, Le Testu 6536 (holotype P). 4. Inversodicraea harrisii (C. Cusset) Cheek comb. nov. http://www.ipni.org/urn:lsid:ipni.org:names:60472992-2 Basionym: Ledermanniella harrisii C. Cusset, Bull. Mus. Natl. Hist. Nat. 4e sér., 5, B, Adansonia 4: 374 (1983). Type: Sierra Leone, Harris 41 (holotype P). 5. Inversodicraea paulsitae (C. Cusset) Cheek comb. nov. http://www.ipni.org/urn:lsid:ipni.org:names:60472993-2 Basionym: Ledermanniella paulsitae C. Cusset, Bull. Mus. Natl. Hist. Nat. 4e sér., 5, B, Adansonia 4: 378 (1983). Type: Gabon. Le Testu 6510 (holotype P). 6. Inversodicraea torrei (C. Cusset) Cheek comb. nov. http://www.ipni.org/urn:lsid:ipni.org:names:60473134-2 Basionym: Ledermanniella torrei C. Cusset, Bull. Mus. Natl. Hist. Nat. 4e sér., 5, B, Adansonia 4: 386 (1983). Type: Mozambique, Torre 5155 (holotype LISC). 7. Inversodicraea thollonii (Baill.) Cheek comb. nov. http://www.ipni.org/urn:lsid:ipni.org:names:60473135-2 Basionym: Podostemum thollonii Baill., Bull. Mens. Soc. Linn. Paris 2: 877 (Baillon 1890). Type: Gabon, Thollon 825 (holotype P). Inversodicraea pepehabai Pepe Haba 292, here described as Inversodicraea pepehabai, is one of the first records of Podostemaceae from the Guineé Forestière Region in the Loma-Man Highlands of the Republic of Guinea (Guinea-Conakry) possibly as a result of insufficient previous collecting effort. In contrast, the waterfalls of the Fouta Djalon Highlands of that country are much better known for multiple species of Podostemaceae (see for example Taylor 1953). KEW BULLETIN (2016) 71:55 Page 3 of 8 55 Since the flowers of Pepe Haba 292 are inverted in the spathellum, and the ellipsoid ovaries and fruits are circular in section, with eight longitudinal ribs, this specimen would clearly have been placed in Ledermanniella Engl. in the prevailing classification of African Podostemaceae by Cusset (1973, 1974, 1978, 1983, 1987). However, since the stems possess numerous scale-like leaflets, it is placed here in the genus Inversodicraea (formerly Ledermanniella subgenus Phyllosma C. Cusset, revised by Cusset (1983)). In Cusset’s 1983 treatment it keys out as L. adamesii (G. Taylor) C. Cusset (now Inversodicraea adamesii G. Taylor) since it has irregularly and shallowly 2 – 3lobed leaflets which are scattered, covering < 50% of the stems. However, it differs from that species in the characters detailed in Table 1 below. Inversodicraea pepehabai Cheek sp. nov. Type: GuineaConakry, Guineé-Forestère, Seredu, Mt Ziama, 8°21'25.8"N, 9°18''30.7"W, fl. fr. 8 Feb. 2010, Pepe M. Haba 292 (holotype HNG!, isotypes K!, P!). http://www.ipni.org/urn:lsid:ipni.org:names:60473136-2 Annual (probably), erect, densely branched herb, 3 – 7.5 cm tall (excluding the leaves), attachment to substrate unknown. Stems in wefts, each main axis with 5 – 15 lateral branches, one or two of which are as equally developed as the main axis, so that 8 – 20 stem apices are developed distally, equidistant from the base (Fig. 1A and B). Stems erect, terete, 0.5 – 0.9 mm diam., ± evenly (densest at stem apices) 30 – 40% covered, in leaflets. Leaflets patent, ovate to obovate in outline, (0.3 –) 0.4 – 0.6 mm long, entire, or with 1 or 2 shallow, short (about 1/10 the length of the leaflet, i.e. c. 0.05 mm long) triangular lateral lobes, apex acute to obtuse, basal attachment as broad, or almost as broad as the leaflet. Leaves falling from stems at anthesis (fruiting stems leafless), arising at stem apex, terminal, flattened, 0.4 – 1.5 cm × 0.1 mm dichoto- mously branching 2 – 4-times in the distal halves, apices acute. Spathellae single, terminal on stems, probably obovoid in bud, c. 2 × 0.75 – 1.2 mm. Flower inverted in bud; pedicel 2 – 2.5 (– 3) mm long at anthesis, not accrescent; tepals two, filiform, 0.6 – 0.75 mm long, inserted on the gynophore. Androecium of a single stamen, erect, not extending above the ovary, (1.2 –) 2 – 4 mm long, anther cells 4, equal, 0.25 (– 0.5) mm long. Pollen in monads. Gynoecium: gynophore 0.2 – 0.8 (– 1) mm long; ovary unilocular, narrowly ellipsoid, 0.9 – 1.3 × 0.5 mm, orbicular, not flattened in transverse section, with 8 subequal, equidistant, parallel longitudinal ribs, those of the sutures as prominent as the remaining 6; stigmas two, botuliform 0.7 – 1.0 × 0.15 mm, held at c. 180° apart. Fruit of similar dimensions to ovary, ribs cylindrical in section c. 0.05 mm diam., styles caducous. Seed planoconvex, papillate, 0.2 – 0.25 × 0.1 × 0.8 mm. Figs 1 – 3. RECOGNITION. Similar to Inversodicraea adamesii in the irregularly-lobed (lobes 1, 2 or absent) leaflets which cover < 50% of the stem. Distinct in the leaflets being patent (not ± appressed), the flowers with 1 stamen (not 2), the fruits 8-ribbed (not 6). DISTRIBUTION. Republic of Guinea (Guinea-Conakry). SPECIMEN EXAMINED. GUINEA-CONAKRY . GuineéF o r e s tè r e , S e r e d u , Mt Z i a m a , 8 ° 21 ' 2 5 . 8 " N , 9°18'30.7"W, fl. fr. 8 Feb. 2010 Pepe Haba 292 (holotype HNG!, isotypes K!, P!). ECOLOGY. Rapids in submontane evergreen forest; c. 600 m asl. CONSERVATION. Inversodicraea pepehabai is here assessed as Endangered under Criterion D of IUCN (2001), since less than 250 individuals are estimated to have been observed at the single location known (EN D1). The area of occupancy (AOO) is assessed as 1km2 using the 1km2 grid preferred by IUCN for riverine organisms. Currently there are no obvious threats, but should tea and/or quinine plantations, or timber extraction be resumed inside the Ziama Foret Classé, there is a Table 1. The significant diagnostic characters separating Inversodicraea adamesii and I. pepehabai. Habit Leaflet shape No. stamens/flower No. ribs on fruit Leaf: Flower length Pedicel length Androecium:Gynoecium length Filament length Stigma shape Inversodicraea adamesii Inversodicraea pepehabai branches spreading, tending to horizontal lanceolate 2 6 1:3 c. 10 mm 2:1 5 – 8 mm subulate stems and branches always erect ovate to obovate 1 8 2:1 2 – 2.5 ( – 3) mm 0.8:1 (1.2 –) 2 – 4 mm botuliform © The Board of Trustees of the Royal Botanic Gardens, Kew, 2016 55 Page 4 of 8 KEW BULLETIN (2016) 71:55 Fig. 1. Inversodicraea pepehabai. A habit of larger plant, with fruit, leaves have been shed; B habit of smaller, flowering plant, leaves still attached; C detail of B, showing 2 – 4 times dichotomously branched leaves; D stem with flower at anthesis, and fruits before dehiscence; E flower emerging inverted from spathellum; F flower approaching anthesis: ovary not yet erect; G leaflet variation: entire, 2 – 3 lobed; H fruit, transverse section showing 8 ± equally developed ribs; J seed, surface papillate. From Pepe Haba 292. DRAWN BY ANDREW BROWN. © The Board of Trustees of the Royal Botanic Gardens, Kew, 2016 KEW BULLETIN (2016) 71:55 risk that surface run-off would raise levels of nutrients and silt in entering the water course in which I. pepehabai is found, increasing algal-growth, that would compete with, and (due to the increased silt levels), reduce establishment of new plants of the species. It is to be hoped that additional records of this species will be found at further sites, lowering its threat assessment. Inversodicraea pepehabai is one of several plant species unique to the Ziama Massif inside the Ziama Man & Biosphere reserve. It is likely to be proposed in future as an “Important Plant Area” for Guinea (see Darbyshire, continuously updated). ETYMOLOGY. Named for the collector of the only known specimen, Pepe Haba of N’zerekore, one of the most expert field botanists in Guinea. Discussion The species described here as Inversodicraea pepehabai is unusual among African Podostemaceae being found in the rapids of a submontane forest area. Other species with this ecology are Saxicolella Page 5 of 8 55 amicorum J. B. Hall (Hall 1971; pers. obs. Cheek), Ledermanniella letouzeyi Cusset (Cusset 1987; Cheek et al. 2004), L. onanae Cheek (Cheek 2003; Cheek et al. 2004) and L. pollardiana Cheek & Ameka (Cheek & Ameka 2008). Most other species of the genus occur in rapids of lowland forest or woodland habits. The affinities of Inversodicraea pepehabai are probably with other West African species of the genus which have slender, usually lobed, leaflets. At first sight Inversodicraea pepehabai appears very similar to the relatively common and widespread I. ledermannii Engl., but the leaflets in that species are consistently, deeply and equally 3-lobed, and cover most of the stem, being ± appressed, not patent. The leaflets of I. pygmaea G. Taylor (L. taylori C. Cusset) are also similar, but are also consistently 3-lobed resembling I. ledermannii excepting that the central lobe is always longer than the laterals, and again, the stems are short (1 – 2 cm long) and completely covered in leaflets. In I. mortonii the leaflets are needle-like, and completely lacking lobes. It is with I. adamesii that the closest similarity of leaflet shape occurs, but the Fig. 2. Inversodicraea pepehabai. Plants in flower at the type locality at Mt Ziama, Feb. 2010. PHOTO BY PEPE HABA. © The Board of Trustees of the Royal Botanic Gardens, Kew, 2016 55 Page 6 of 8 KEW BULLETIN (2016) 71:55 Fig. 3. Inversodicraea pepehabai. Plants in situ on vertical rock face at the type locality at Mt Ziama, Feb. 2010. differences in habit, flower and fruit leave no doubt that they are distinct species (see Table 1). Inversodicraea pepehabai is among a host of new species that have been brought to light and published from the Republic of Guinea in the last seven years, following decades of relative inactivity in plant species discovery in that country and its neighbours. Examples of such newly discovered species in Guinea are: Brachystephanus oreacanthus Champl. (Champluvier & Darbyshire 2009), Xysmalobium samoritourei Goyder (2009), Gymnosiphon samoritoureanus Cheek (Cheek & van der Burgt (2010)), Striga magnibracteata Eb. Fisch. & I. Darbysh. (Fischer et al. 2011), Eriosema triformum Burgt (van der Burgt et al. 2012), Eriocaulon cryptocephalum S. M. Phillips & Mesterházy (2015), Napoleonea alata Jongkind (Prance & Jongkind 2015) and Psychotria samoritourei Cheek (Cheek & Williams 2016). Just over the border in Mali, Calophyllum africanum Cheek & Luke (2016) was recently found, and in Ivory Coast Macropodiella © The Board of Trustees of the Royal Botanic Gardens, Kew, 2016 PHOTO BY PEPE HABA. cussetiana Cheek (Cheek & Ameka 2016). Even a new rheophytic genus, Karima Cheek & Riina has come to light in Guinea (Cheek et al. 2016). Acknowledgements Professor Basile Camara and Dr Seydou Magassouba, respectively Director General and Director-Adjoint, Université de Gamal Abdel Nasser-Herbier National de Guinée, are thanked for arranging permits and for their long term support and collaboration. Janis Shillito is thanked for typing the manuscript. George Gosline assisted with access to electronic specimen data. 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