Paracephaelis tiliacea Baill.

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 : 80-83

Paracephaelis tiliacea Baill.

Figs 1H , 2A , A’, B, 21

Adansonia 12: 316 ( Baillon 1879); Histoire des Plantes 7: 496 ( Baillon 1880); Notulae Systematicae 16: 9, pl. 1, 1–7 ( Arènes 1960).

Type: MADAGASCAR – Mahajanga Province, Boeny Region, Soalala District • Ambongo ; 14 Feb. 1841; fr; Pervillé 633; holotype: P [ P00274300 ]; isotypes: K, P [ P00115282 ], P [ P00274301 ].

Other material studied

MADAGASCAR – Mahajanga Province, Boeny Region, Soalala District • Ambongo ; Jan. 1906; fr; d’Alleizette 1472; P . – Mahajanga I District • Majunga , dunes; Jan. 1921; Perrier de la Bâthie 13452; K, L, P . – Melaky Region, Antsalova District • forêt de Tsimembo , E d’Ambereny (Antsalova) ; 29–31 Mar. 1966; fr; Capuron 24573-SF; BR, P, TEF . – Toliara Province, Menabe Region, Morondava District • forêt de Marosalaza , 50 km N de Morondava; 0 m a.s.l.; 28 May 1974; fr; Abraham 88, part A; BR, P • Kirindi forest, along RN 8 to Belo-Tsiribihina; 64 m a.s.l.; 21 Feb. 2018; fl; Atalahy, Razafindrahaja, Swenson & Razafimandimbison 111; BR n.v., MO n.v., P online, S n.v., TAN n.v . • forêt de Kirindi (forêt d’Andalandahalo) , Pandanus walk , by the river Kirindry, 45 km NE of Morondava; 20 m a.s.l.; 21 Feb. 2000; fr; Davis, Rakotonasolo & Wilkin 2580; BR, K, P, TAN • between Marofadilia and Tsimafana, on road to Belo, ca 68.5 km ( GPS) NE of Morondava; 5 m a.s.l.; 22 Feb. 2000; fl; Davis, Rakotonasolo & Wilkin 2585; BR, K, P, TAN • Kirindi forest , N part, piste vers le point de vue km 7; 89 m a.s.l.; 19 Jan. 2007; fl; De Block, Rakotonasolo, Groeninckx & Dessein 2172; BR, K, MO, P, TAN • Lamboukily , 14 km of basement camp in Kirindi; 30 m a.s.l.; 20 Jan. 2007; fl; Groeninckx, Rakotonasolo, Dessein & De Block 113; BR, G, MO, P, TAN • commune Bemanonga, Andranomena Reserve ; 18 Mar. 2011; fr; Kainulainen, Razafimandimbison, Razafindraibe & Wikström 167; BR, S.

Description

Shrub, 2–5 m tall, or small tree, 5–6 m tall, dbh 2–10 cm; Terminalia -branching pattern; pubescence reddish brown, tawny or whitish. Young shoots brown or reddish brown (because of pubescence), densely covered with long erect hairs; older branches greyish or greyish brown, glabrous. Leaves clustered at the end of long and short shoots, probably deciduous. Petioles 1–3 cm long, densely covered with long erect hairs. Leaf blades broadly elliptic or broadly ovate, often orbiculate, 7–20 × 5–15 cm, papyraceous to subcoriaceous, drying brown or greenish brown above and somewhat paler below, upper surface moderately to densely covered with short erect hairs (hairs denser and somewhat longer on midrib and secondary veins), lower surface densely covered with long erect hairs; base strongly cordate, cordate or unequally truncate; tip shortly acuminate, acumen 2–10 mm long; domatia absent; 5–8 secondary veins on each side of midrib, impressed above, prominently raised below; higher order venation visible or inconspicuous above, visible below. Stipules caducous, triangular with short needle-like awn, keeled; outer surface of youngest stipule pairs densely covered with long erect hairs, inner surface glabrous with row of colleters interspaced with long hairs at the base; sheath 4–7 mm long; awn 0.5–2 mm long. Inflorescences terminal on short lateral shoots with leaves fallen, later becoming pseudo-axillary, sessile, compact, 1–7 × 2–7 cm, with numerous flowers; inflorescence parts densely covered with long erect hairs; first order axes 0.5–1.5 cm long; second order bracts with stipular parts broadly triangular, up to 4 mm high, and foliar parts trilobed, consisting of a basal sheath 1–1.5 mm long, topped by triangular lobes, central lobe 4–8 mm long, lateral lobes 1–2 mm long; higher order bracts with stipular parts reduced or absent, foliar parts triangular and vaulted, 3–4 mm long, or trilobed with central lobe up to 4 mm long; bracteoles on pedicel just below ovary, opposite, stipular parts absent, foliar parts narrowly triangular, 2–3 mm long, tips acute. Flowers sessile or shortly pedicellate, pedicels 0–2 mm long. Calyx densely covered with ± long erect hairs outside, inner surface densely covered with long appressed hairs; tube 0.5–0.7 mm long; lobes triangular, (1.5–) 2–3.5 mm long, tips acute. Corolla tube 7–9 mm long, inner surface sparsely covered with appressed hairs over entire length; lobes 4.5–5 mm long. Anthers ca 5 mm long, basal part (ca 1 mm long) often included in corolla tube at anthesis; filaments ca 0.5 mm long. Ovary 2–3 mm long, densely covered with ± long erect hairs; per locule 4–10 ovules arranged at periphery of placenta attached to upper half of septum, rarely with some ovules on abaxial surface of placenta. Style and stigma 14–18 mm long, exserted for 5–8 mm; style moderately covered with long upwardly directed hairs from ca 3.5 mm from base to just below papillate zone; stigmatic lobes 7–9 mm long. Fruits ovoid, faintly ribbed longitudinally (when dried), ca 7 × 5 mm, densely covered with ± long erect hairs; fruit wall thin, with sclerified vascular bundles; pyrenes hemi-ovoid, ca 5 × 3 mm, crustaceous, with rounded base, acute tip, small adaxial opening somewhat above the middle and longitudinal central ridge running from the apex to the top of the adaxial opening and continuing into a longitudinal depression below it. Seeds 1–2(–6) per fruit, 3–3.5 × 2.7–3 mm.

Distribution

Restricted to western Madagascar. Recent material is only known from the region of Kirindy Forest in Morondava. Present in: Soalala and Mahajanga I Districts, Boeny Region, and Antsalova District, Melaky Region (Mahajanga Province); Morondava District, Menabe Region (Toliara Province) ( Fig. 23D ).

Habitat and phenology

Low-elevation dry deciduous forest; on white sand or laterite; elev. 0– 650 m. Flowers: January–February; Fruits: February–May.

Vernacular name

Papolany (Abraham 88).

Provisional IUCN assessment

Endangered: EN B2ab(iii). This assessment is based on 11 collections with detailed locality data, collected between 1841 and 2018. Using GeoCAT, the EOO of P. tilia is estimated to be 39 353 km 2, far exceeding the upper limit of any threat category under criterion B1. However, this seems to be an overestimation since it includes a large inland region, whereas P. tiliacea typically occurs less than 50 km from the coast. The AOO is 36 km 2, which complies with the Endangered category under criterion B2. The species occurs in 4 locations, which complies with the Endangered category under subcriterion ‘a’ of criterion B2. Most specimens are collected from the Menabe-Antimena Protected Area, and more specifically from Kirindi Forest (1 location). A second location is in the protected area of Tsimembo Manambolomaty. From the other two locations (Majunga and Ambongo), no specimens were collected after 1921. The dry deciduous forests in western Madagascar are being destroyed at a more rapid pace than any other Malagasy forest type ( Moat & Smith 2007). Clearing for subsistence farming, bushfires, and logging for wood and for the production of charcoal are the main threats ( Moat & Smith 2007). These threats also affect the two protected areas, Menabe-Antimena and Tsimembo Manambolomaty ( Filou 2019; BirdLife International 2020c). Another important factor in the Menabe-Antimena Protected Area is the clearance of forest for the production of the cash crop corn. Rates of deforestation in the region are unprecedented with predictions that more than 80% of the forest in the Menabe-Antimena region could be cleared by 2025 ( Vieilledent 2016; Filou 2019; Hudson et al. 2020). The main threat to P. tiliacea is the destruction of its habitat for the above-mentioned factors and a reduction in the extent and quality of its habitat is inferred. This, in combination with the low AOO and the low number of locations, qualifies the species for Endangered status.

Note

Fruit and seed characters are based on a single fruiting specimen, Abraham 88, from which two immature fruits were studied. In one fruit, each of the two pyrenes enclosed a single developing seed and several aborted ones, resulting in two potentially viable seeds. In the other fruit, the two pyrenes developed, but one of these only contained aborted seeds, resulting in a single viable seed. It is presumed here that more seeds can develop within a single fruit. The fruit size given is the size of the boiled immature fruits.

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. 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).