Paracephaelis saxatilis (Scott Elliot) De Block

Block, Petra De, 2022, Monograph of the western Indian Ocean genus Paracephaelis (Rubiaceae - Pavetteae), with description of thirteen new species, European Journal of Taxonomy 801, pp. 1-99 : 67-72

Paracephaelis saxatilis (Scott Elliot) De Block

Figs 1C, G , 2D , 4C–D, F, I, K , 18

Systematics and Geography of Plants 73: 100 ( De Block 2003).

Basionym

Webera saxatilis Scott Elliot , Journal of the Linnean Society 29: 25 (Scott Elliot 1891). Type: MADAGASCAR – Toliara Province, Anosy Region, Taolagnaro District • Fort Dauphin ; May [1888–1890]; fr; Scott Elliot 2885; lectotype: K, here designated. Syntype: MADAGASCAR • s.loc.; Scott Elliot 2683 (n.v.). See Note.

Homotypic synonym

Tarenna saxatilis (Scott Elliot) Homolle , Bulletin de la Société botanique de France: 607 ( Homolle 1938); Révision des Rubiacées de Madagascar et des Comores: 175 ( Capuron 1973).

Heterotypic synonyms

Myonima velutina Cordem., Flore de l’île de la Réunion: 508 ( De Cordemoy 1895). – Tarenna velutina (Cordem.) Verdc., Kew Bulletin 37: 561 ( Verdcourt 1983). Type:?RÉUNION • s.loc.; s.dat.; fl (corollas fallen); Bernier s.n. (voyage de M. Boivin, ex Herb. Bernier); holotype: P; isotype: Herb. Cordemoy MARS.

Other material studied

MADAGASCAR – Toliara Province, Androy Region, Ambovombe-Androy District • versant méridional du massif de l’Angavo , E d’Antanimora; 23 Jan. 1963; fr; Capuron 22477-SF; BR, P • along road between Ambondro and Ambovombe; 100–150 m a.s.l.; 18 Feb. 1975; fr; Croat 31689; MO • Antanimora , N d’Ambovombe; 29 Apr. 1931; fr; Decary 8867; P • route d’Antanimora; 12 Jan. 1956; fl; Descoings 1447; P • Vohipary forest ; 539 m a.s.l.; 20 Apr. 2001; fr; Miles & Randriantarika 142; K • Antamimora , bifurcation de Bekibio; 16 Feb. 1961; fr; Peltier J. & M. 2871; P • Antanimora, on road to Beraketa; 341 m a.s.l.; 18 Dec. 2004; fl; Rakotonasolo, Hoffmann, Rakotoarisoa & Ralimanana 922; BR, K. – Beloha District • falaise côtière NW du cap Sainte-Marie, vers Lavanono ; 1–150 m a.s.l.; 8 Mar. 1955; fl; Humbert 29322; P • falaise côtière vers l’embouchure de la Menarandra , Bevoalava- Ankazondranto; 1–150 m a.s.l.; 12 Mar. 1955; fl; Humbert 29378; BR, P. – Bekily District • vallée supérieure de la Manambolo (bassin du Mandrare) , aux environs de Beaka (Pisopiso) ; 800 m a.s.l.; Jan. 1934; fl; Humbert 13684; BR, P • bassin de réception de la Mananara , affluent du Mandrare , pentes occidentales des montagnes entre l’Andohahela et l’Elakelaka, aux dessus de Pisopiso (Beaka); 1100 m a.s.l.; Dec. 1933 – Jan. 1934; fl; Humbert 13684bis; BR, P . – Anosy Region, Amboasary-Atsimo District • vallée du Mandrare ; Oct. 1905; fl, fr; d’Alleizette 3175; L • near Amboasary, due E of Ambovombe; 150 m a.s.l.; 19 Feb. 2001; fl; Davis & Rakotonasolo 2731; BR, K, MO, P, TAN, TEF • Mandrare moyen , environs de Beza Esiva ; 27 Feb. 1957; fr; Descoings 2737; TAN • bassin supérieure de l’Onilahy ( Mangoky ), vallée de l’Andranomiforitra ; 1000–1200 m a.s.l.; 19 Dec. 1928; fl; Humbert 7072bis; P • vallée moyenne du Mandrare , près d’Anadabolava ; 200–250 m a.s.l.; Dec. 1933; fl; Humbert 12399; P • ibid.; 200–250 m a.s.l.; Dec. 1933; fl; Humbert 12556; P • ibid., mont Vohitrosy ; 800 m a.s.l.; Dec. 1933; fl; Humbert 12696; P • vallée de la Manambolo (bassin du Mandrare) , NW de Maromby (Betsioky); 300–400 m a.s.l.; Dec. 1933; fl; Humbert 12768; BR, P • vallée de la Manambolo (bassin du Mandrare) , rive gauche, aux environs d’Isomony (confluent de la Sakamalio), monts Kotriha et Isomonobe; 400– 600 m a.s.l.; Dec. 1933 – Jan. 1934; fl; Humbert 12823; BR, P • vallée de la Manambolo (bassin du Mandrare), rive droite, aux environs d’Isomony (confluent de la Sakamalio); 400–900 m a.s.l.; Dec. 1933; fl; Humbert 12954; BR, P • Marotsiraka, forêt de Betsimalaho , colline Beanivo ; 222 m a.s.l.; 20 Apr. 2012; fr; Raharimampionona, Ravelonarivo & Josso 399; MO n.v., P online, TAN n.v . • Ranobe, Betsingilo, forêt de Beanivo , complexe Anadabolava Betsimalaho ; 282 m a.s.l.; 12 Feb. 2013; fr; Randrianarivony, Randriatsivery, Botovao & Remanofy 509; BR, MO n.v., P n.v., TAN n.v. – Taolagnaro District • forêt de Vinanibe , près de Fort-Dauphin ; 9 Jan. 1963; fl; Capuron 22314-SF; BR, P • dune d’Eolala , entre le Vinanibe et Fort-Dauphin; 4 Feb. 1963; fl; Capuron 22317-SF; BR, P • Vinanimbe (Ambimanibe), coastal forest 8 km WSW (BRG 237º) of Taolanaro; 10 m a.s.l.; 4 Dec. 1997; fr; Davis, Andriantiana & Gower 1192; K, P, TAN • Fort Dauphin ; s.dat.; fl; Cloisel 196; BM, P • woods around the airport , W side of Fort Dauphin; 10 m a.s.l.; 10 May 1983; fl, fr; D’Arcy & Rakotozafy 15413; MO • ibid.; 10 m a.s.l.; 10 May 1983; fl, fr; D’Arcy & Rakotozafy 15414; MO, P • ibid.; 10 m a.s.l.; 10 May 1983; fr; D’Arcy & Rakotozafy 15418; MO • Petriky forest ; 20 m a.s.l.; 18 Feb. 2001; fl; Davis & Rakotonasolo 2727B; BR, K, TAN, TEF • Petriky, Eharake ; 47 m a.s.l.; 31 Mar. 2010; fl; De Block, Groeninckx & Rakotonasolo 2396; BR, G, K, MO, P, TAN • Petriky , near guard’s cabine; 47 m a.s.l.; 31 Mar. 2010; fl; De Block, Groeninckx & Rakotonasolo 2401; BR, G, K, MO, P, TAN • Fort-Dauphin ; 28 Jun. 1926; fl; Decary 4207; P, LISC • Fort-Dauphin ; 28 Jun. 1926; fr; Decary 4208; P, WAG • Italy , côte W de Fort Dauphin; Mar. 1955; fl, fr; Descoings 426; TAN • Mandena ; 0–10 m a.s.l.; 10 Mar. 1989; fr; Dumetz, Gereau & Rabevohitra 557; K, MO, P, TAN • Mandena ; 0–10 m a.s.l.; 23 Jan. 1990; fl; Dumetz 1230; K, MO, P, WAG • fir. Mananbaro, Petriky forest, S of large dune near NE corner of lake Andranany, ca 10 km WSW of Tolanaro; 0–10 m a.s.l.; 10 Apr. 1989; fr; Gereau, Rabevohitra & Dumetz 3343; BR, K, MO, P, TAN, WAG • dunes de Fort Dauphin ; 27 Mar. 2010; fr; Groeninckx, De Block & Rakotonasolo 289; BR, K, MO, P, TAN • baie des Galions ( Ranofotsy ), SW de Fort-Dauphin; 1–100 m a.s.l.; Feb. 1955; fl; Humbert 28991; P • Petriky ; 14 m a.s.l.; 7 Sep. 2006; fr; Landry 131; K • hauts bassins de la Mananara et abords , N d’Imonty , RNI 11, Andohahela ; 400–1900 m a.s.l.; 3 Dec. 1960; fl; Leandri & Saboureau 4224; P • Petriky , WSW of Fort-Dauphin, at junction of main QMM road and side road; 5 m a.s.l.; 13 Mar. 1998; fl, fr; Lowry, Smith, Vincelette & Randrihasipara 5025; BR, K, MO, P • Petriky , along roads near and beyond dune near end of QIT road; 25 m a.s.l.; 8 Dec. 1989; fl; McPherson & Dumetz 14670; K, MO, P, TAN • Petriky , along QIT road; 15 m a.s.l.; 12 Jan. 1990; fl; McPherson, Dumetz & Rabevohitra 14764; K, MO, P, TAN, TEF • Petriky , along coastline near S end of the most SW lake; 10 m a.s.l.; 22 Jan. 1990; fl; McPherson, Dumetz & Rabevohitra 14850; MO • Mandena forest ; 2–15 m a.s.l.; 23 Jan. 1990; fl; McPherson, Dumetz & Rabevohitra 14875A; MO, P, TAN • 5 km S of Manambaro, 23 km W of Fort Dauphin; 150 m a.s.l.; 30 Mar. 1991; fl; Miller & Randrianasolo 6231; K, MO, P, TAN • Fort Dauphin ; 1955; fr; Pernet 38; TAN • fir. Manambaro, village Ambovo , forêt littorale de Petriky ; 6 m a.s.l.; 24 Jun. 2004; fr; Rabenantoandro, Ramisy, Rajoharison & Randriatafika 1609; BR, K, MO • Andrakaraka , forêt littorale de dune haute à côté du site de construction du seuil déversoir de QMM; 8 m a.s.l.; 27 Feb. 2007; fr; Rabenantoandro, Randriatafika, Ramison, Rajoharison & Théodore 1790; BR, MO n.v., P online, TAN n.v . • Petriky ; 5 Dec. 2002; fl; Rakotonasolo, Randrinaivo, Rabevohitra, Rzafindrabeaza & Ratodimanana 573; BR, K, P • forêt littorale de Sainte Luce ; 8 Jan. 2008; fl; Ramison & Rabehevitra 514; MO n.v., P online, TAN n.v . • Ambatoabo, Ankoba, forêt sèche à Alluaudia d’Ankoba ; 180 m a.s.l.; 24 Feb. 2009; fl, fr; Randrianaivo, Ratovoson, Razanatsoa, Razafindrahaja, Rasolondrainy Tsimitamby & Fiadana 1749; BR, MO, P • fir. Manambaro, fkt. Petriky ; 18 Feb. 2004; fl; Randriatafika & Ramisy 400; BR, MO • Manambaro, forêt littorale de Petriky , située entre le village d’Ambovo et de Loharano; 6 m a.s.l.; 2 Mar. 2004; fl; Randriatafika, Razafimandimby & Ramisy 475; MO n.v., P online • Manambaro, Petriky , forêt littorale de Petriky ; 15 Mar. 2006; fl; Randriatafika & Rabenantoandro 710; MO n.v., P online • ibid.; 22 Mar. 2006; fl; Randriatafika & Rabenantoandro 717; MO n.v., P online • Fort Dauphin ; s.dat.; fl; Scott Elliot 2389; P • Fort Dauphin ; Sep. 1890; fl, fr; Scott Elliot 2389bis; K • Fort Dauphin ; s.dat.; fr; Scott Elliot 2885; K. – Without locality • Feb. 1955; fl, fr; Descoings 316; TAN .

Description

Shrub or small tree, to 4 m tall; pubescence white or tawny; youngest internodes pale or orange brown, rapidly becoming corky, densely covered with appressed or spreading hairs; older branches corky, greyish or fawnish, glabrous. Leaves grouped at the end of lateral short-shoots with short internodes and the older leaves fallen. Petioles 2–5 mm long, densely covered with appressed, spreading or erect hairs. Leaf blades elliptic, ovate, rarely obovate or orbiculate, 1–4 × 0.7–2.8 cm, coriaceous, drying brown, dark brown or greenish above and somewhat paler below, upper surface glossy, moderately to densely covered with short erect hairs or, more rarely, glabrescent, lower surface densely covered with long, erect hairs (hairs often more appressed on midrib and secondary veins); base cuneate, acute, truncate, rounded or somewhat cordate; tip obtuse, rounded or acute, mucronate; domatia absent; midrib sparsely to moderately covered with ± long appressed or spreading hairs above; 3–6(–7) secondary veins on each side of midrib, impressed above, raised below; higher order venation usually inconspicuous on both surfaces, rarely impressed above. Stipules caducous, triangular with short needle-like awn, keeled; outer surface of youngest stipule pairs densely covered with long appressed or spreading hairs, inner surface glabrous with row of colleters interspaced with long hairs at the base; sheath 1–2.5 mm long; awn 0.5–1.5 mm long. Inflorescences terminal on short lateral shoots with short or longer internodes and leaves fallen but stipules or stipular remnants remaining, sessile but leaves of first order bracts often fallen (giving the impression of short peduncle), compact, 0.6–1.5 × 1–2 cm, with 5–45 flowers; inflorescence parts densely covered with appressed or spreading hairs; first order axes 0.2–1 cm long; higher order bracts with stipular parts reduced or absent, foliar parts triangular and vaulted, 1.5–4 mm long; bracteoles on pedicel just below ovary, opposite, stipular parts absent, foliar parts triangular, 1.5–2.5 mm long, tips acute. Flowers sessile or shortly pedicellate, pedicels 0–2(–3) mm long. Calyx densely covered with appressed to spreading hairs outside; tube (0.2–) 0.4–0.7 mm long, inner surface densely covered with appressed hairs; lobes triangular, 0.8–1.5 mm long, inner surface densely covered with appressed hairs all over or pubescence restricted to the base of the lobes, tips acute. Corolla tube 4–7 mm long, inner surface densely covered with long erect hairs in upper ⅔; lobes 3–4.5 mm long. Anthers 3.5–4 mm long, completely exserted or basal part (ca 1 mm long) included in corolla tube at anthesis; filaments 0.5–1 mm long. Ovary ca 1.5 mm long, longitudinally ribbed (when dried), densely covered with appressed to spreading hairs; per locule 3–8 ovules arranged at periphery of placenta attached to top of septum. Style and stigma (8–) 10–12.5 mm long, exserted for 4–5 mm; style densely covered with long upwardly directed hairs from ca 2 mm above base to just below papillate zone; stigmatic lobes 5–6 mm long, upper part fusiform; papillae absent along fusiform part, present lower down in longitudinal grooves. Fruits subspherical, 5–7 × 5.5–8 mm, densely covered with short erect hairs, somewhat glossy; fruit wall thin, with sclerified vascular bundles; pyrenes hemispherical, ca 5.5 × 5 mm, membranous adaxially, crustaceous abaxially, with rounded tip and base, small adaxial opening somewhat above the middle and slight longitudinal central ridge running from the apex to the top of the adaxial opening. Seeds (2–)4–8 per fruit, 3–4 × 2.5–3 mm.

Distribution

Restricted to south-eastern and southern Madagascar. Present in: Ambovombe-Androy, Beloha and Bekily Districts, Androy Region, and Amboasary-Atsimo and Taolagnaro Districts, Anosy Region (Toliara Province) ( Fig. 23D ).

Habitat and phenology

Deciduous dry forest and scrub, littoral forest and dune vegetation; on white sand, more rarely on rocky substrate; elev. 0–1200 m. Flowers: September–October, December–March, May; Fruits: throughout the year, but none recorded in February–March.

Vernacular names

Tinoro (Gereau et al. 3343); taitsanda (Randriatafika & Rabenantoandro 710).

Provisional IUCN assessment

Least Concern: LC. This assessment is based on 61 collections with detailed locality data, collected between 1890 and 2012. The EOO of P. saxatilis is estimated to be 23 637 km 2, somewhat exceeding the upper limit of the Vulnerable category under criterion B1. The AOO is 140 km 2, which complies with the Endangered category under criterion B2. The species occurs in more than 15 locations, which exceeds the upper limit for Vulnerable category under subcriterion ‘a’ of criterion B2. However, at least three locations are severely threatened by mining. QIT Madagascar Minerals (QMM) is a sands mining operation, producing ilmenite, a major source of titanium dioxide, and zircon (https://www.riotinto.com/operations/madagascar/qit-madagascar-minerals). Approximately 1665 ha of littoral forest habitat is expected to be lost between 2008 and 2050 at Mandena (3 specs), Petriky (14 specs), and Sainte Luce (1 spec.). The mining operation clears the vegetation and removes the soil, thereby destroying the seed bank. While part of the forests will be conserved and the company pledges restoration, the mining activities will have a negative effect on the AOO and the number of mature individuals, but not on the EOO, and the number of locations. The main threat to P. saxatilis is the destruction of its habitat, as a result of mining, subsistence farming, charcoal production, and collection of plants for medicinal or subsistence use ( Ingram & Dawson 2006). While a reduction in the extent and quality of the habitat of P. saxatilis can be inferred, the number of locations (> 15) and the relatively large EOO does not qualify this species for a threat category. Therefore, P. saxatilis is assessed as Least Concern.

Note

Webera saxatilis was described based on two syntypes: Scott Elliott 2885 and Scott Elliott 2683 ( Scott Elliott 1891). It has proven impossible to locate the second specimen. Scott Elliott 2885 is only a fragment present in K. There is, however, another specimen of P. saxatilis collected by Scott Elliott, notably 2389 (P) and 2389bis (K). In K, one double of Scott Elliot 2389bis is mounted on the same sheet as Scott Elliott 2885, with the second double on a separate sheet. The labels of Scott Elliot 2389 and 2389bis in both K and P bear the name ‘ Webera saxatilis ’, but the name is absent from the label of Scott Elliott 2885. Possibly, Scott Elliott (1891) erroneously cited the number 2683 instead of 2389bis for the second syntype of Webera saxatilis .

Figures

Fig. 1. Flowers, fruits and stipules of Paracephaelis Baill. A–D. Inflorescences. E–H. Fruits. I–J. Stipules. K–L. Infrutescences. A, E, I. P. cinerea (A.Rich. ex DC.) De Block. B. P. pauciflora De Block sp. nov. C, G. P. saxatilis (Scott Elliot) De Block. D. P. sericea (Arènes) De Block. F. P. ranirisonii De Block sp. nov. H. P. tiliacea Baill. J–K. P. capitulifera De Block sp. nov. L. P. russata De Block sp. nov. Photographs: P. De Block (B–E, G, I–L); S. Dessein (A, H); L. Gautier (F).

Fig. 2. Overview of the placentation in Paracephaelis Baill. A–K. Abaxial views of placenta and ovules. A’. Adaxial view of placenta and ovules with zone of attachment of the placenta indicated. A–C. Typical placentation type of Paracephaelis, with many ovules arranged at the periphery of the placenta.D–E. Idem, with fewer ovules. F–H. Idem, but ovules restricted to the top of the placenta. I. Typical placentation type in P. cinerea (A.Rich. ex DC.) De Block, P. comorensis De Block sp. nov. and P. trichantha (Baker) De Block. J–K. Idem, with fewer ovules. Drawn by Mr A. Fernandez. From Perrier de la Bâthie 13452 (P. tiliacea Baill., A, A’); Pervillé 633 (P. tiliacea Baill., B); Capuron 23451-SF (P. longipedicellata De Block sp. nov., C); McPherson et al. 14875A (P. saxatilis (Scott Elliot) De Block, D); Gautier et al. 4188 (P. gautieri De Block sp. nov., E); De Block et al. 1280 (P. bardotiae De Block sp. nov., F); De Block et al. 1048 (P. russata De Block sp. nov., G–H); Capuron 23073-SF (P. cinerea (A.Rich. ex DC.) De Block, I); Barthelat et al. 732 (P. comorensis De Block sp. nov., J); and Labat & Pascal 2887 (P. comorensis De Block sp. nov., K).

Fig. 4. Pollen of Paracephaelis Baill.; SEM images. A, C. Polar view. B, D. Equatorial view. E–F. Apocolpium. G–I. Mesocolpium. J–K. Ectocolp and mesoaperture. L. Endocolp with annulus. M. End of endocolp, diverging into terminal horns. N–O. Pollen wall. From Lebosaka 9397-RN (P. longipedicellata De Block sp. nov., A–B, E, G, M–N); Dumetz 1230 (P. saxatilis (Scott Elliot) De Block, C–D, F, I, K); and Capuron 20419-SF (P. seyrigii De Block sp. nov., H, J, L, O).

Fig. 18. Paracephaelis saxatilis (Scott Elliot) De Block. A. Flowering branch. B. Stipule. C. Bracteole, ovary and calyx. D. Corolla, stamens, style and stigma. E. Fruit. Drawn by Mr A. Fernandez. From McPherson et al. 14764 (A–D) and Gereau et al. 3343 (E).

Fig. 23. Distribution maps of Malagasy species of Paracephaelis. A. P. aristata De Block sp. nov. (black dot), P. bardotiae De Block sp. nov. (blue dot), P. capitulifera De Block sp. nov. (green dot), P. gautieri De Block sp. nov. (red dot), and P. grandifructa De Block sp. nov. (yellow dot). B. P. cinerea (A.Rich. ex DC.) De Block (black dot). C. P. longipedicellata De Block sp. nov. (black dot), P. orientalis De Block sp. nov. (blue dot), P. pauciflora De Block sp. nov. (green dot), P. ranirisonii De Block sp. nov. (red dot), and P. seyrigii De Block sp. nov. (yellow dot). D. P. russata De Block sp. nov. (black dot), P. sambavensis De Block sp. nov. (blue dot), P. saxatilis (Scott Elliot) De Block (green dot), P. sericea (Arènes) De Block (red dot), and P. tiliacea Baill. (yellow dot).