Panicum pleianthum Peter in Repert. Spec. Nov. Regni Veg. Beih. 40(1, Anhang): 47. 1930

Vorontsova, Maria S., 2018, Revision of the group previously known as Panicum L. (Poaceae: Panicoideae) in Madagascar, Candollea 73 (2), pp. 143-186 : 172

23. Panicum pleianthum Peter in Repert. Spec. Nov. Regni Veg. Beih. 40(1, Anhang): 47. 1930 .

Lectotypus (designated here): TANZANIA. Prov. Tanga: Lushoto District, Mwele to Tanga , Maramba , 9.VI.1917, Peter 20738 ( W [ W1960-0020873 ] image seen; isolectotype: G [ G00022437 ] image seen) .

= Cyrtococcum nossibeense A. Camus in Bull. Soc. Bot. France 99: 144. 1952. Lectotypus (designated here): MADAGASCAR. Prov. Antsiranana: Nosy Be , bois de Lomonbe , au dessus de Passandasa , III.1851, Boivin s.n. ( P [ P02263115 ]!) . Syntypi: MADAGASCAR. Prov. Antsiranana: Nosy Be , s.d., Boivin s.n. ( P [ P02263117 ]!) ; ibid. loco, III.1847, Boivin s.n. ( P [ P02263116 ]!), syn. nov.

Creeping ascendant perennial, branched, to 60 cm long, the culms and nodes finely pilose. Leaf sheaths pilose. Ligule a ciliolate membrane. Leaf blades lanceolate, flat, chartaceous, 5 – 10 × 0.6– 1 cm, drying yellow-green, distichous, asymmetric at base, pilose on both sides. Panicles terminal, fully exserted, 4–20 cm long, narrowly ovate, compact, the branches ascending, glabrous to sparsely pilose. Spikelets narrowly ovate, asymmetric, apically acute, 1.7–2.2 mm long, brown even on young plants, never gaping open. Lower glume ½as long as the spikelet, chartaceous, apically obtuse, 3–5-veined, glabrous or finely pilose, clearly separated from the rest of the spikelet by an internode c. 0.5 mm long. Upper glume a little shorter than the spikelet exposing the upper lemma at maturity, herbaceous, 5-veined, glabrous or finely pilose. Lower floret barren, with a partly developed palea. Lower lemma herbaceous, 5-veined, glabrous or finely pilose. Upper lemma smooth, shiny, brown.

Distribution and ecology. – Kenya, Tanzania, Mozambique, and Madagascar’s coastal forest in eastern and north-western parts of the island, 0–350 m ( Fig. 10B ).

Notes. – Spikelets of this species appear a little asymmetric and the compression is close to lateral, unlike the symmetric and dorsally compressed spikelets typical of Panicum s.l. Malagasy plants were originally described in the genus Cyrtococcum Stapf. due to this spikelet morphology and annotated as C. nossibeense . This is clearly the same species as the African Panicum pleianthum ; generic placement will be confirmed following phylogenetic analysis. Inflorescences always appear to be brown and dry, even on freshly collected plants with green culms and leaves. This species is distinct with no close relatives apparent.

The holotype of P. pleianthum was confirmed missing from B in October 2016 (Robert Vogt, pers. comm.); of the two known extant duplicates the W sheet has the best material and is selected as the lectotype. P holds three unnumbered collections of this species made by Boivin in Nosy Be and annotated by Camus as Cyrtococcum nossibeense ; the sheet P [P02263115] is chosen as the lectotype due to its best material and most extensive original label data.

This species is illustrated in CLAYTON (1989: Tab. 7).

Additional material examined. – MADAGASCAR. Prov. Antsiranana: Ampasindava, forêt de Betsitsika , 13°45'44"S 47°59'50"E, 13.I.2009, Ammann et al. 250 ( G [ G00180384 ]) ; Lokobe , IV.1970, Bosser 20130 ( K [ K000805554 ], P [ P02222321 ]) ; ibid. loco, IV.1970, Bosser 20136 ( P [ P02325390 ]) ; presqu’île d’Ampasindava , V.1970, Bosser 20143 ( K [ K000805553 ], P [ P02222314 ]) ; entre Ambodisakoana et Ambalafary , 14°04'S 48°17'E, 23.VI.1994, Gautier et al. 2414 ( G [ G00418798 ], K [ K000805555 ], P [ P02325450 ]) ; Ampasindava , forêt de Betsitsika , 13°45'27"S 47°58'53"E, 20.I.2009, Madiomanana et al. 243 ( G [ G00181509 ]) ; PK 90 rte Sambava-Andapa après Andrakata , XI.1967, Morat 2823 ( P [ P02307377 ]) ; Befalafa, Ambahatra , 13°55'53"S 48°27'15"E, 10.V.1999, Wohlhauser & Andriamalaza 60118 ( G, K [ K000805557 ], P [ P04430797 ]) ; Manongarivo, Ambahatra , 13°54'00"S 48°28'E, 3.V.2000, Wohlhauser 60244 ( G, K [ K000805556 ], P [ P06768575 ]) . Prov. Fianarantsoa: Kianjavato , I.1964, Bosser 18999 ( P [ P02307330 ]) ; Ambahy, Nosy Varika , 20°49'47"S 48°28'58"E, 23.IV.2004, Razakamalala et al. 1201 ( P [ P02309324 ]) . Prov. Toamasina: Fénérive, rte de Vavatenina , XI.1954, Bosser & Descoings 84 ( P [ P02309295 ]) ; Ambanivoules , IV.1837, Goudot s.n. ( G [ G00418809 ]) . Prov.Toliara: Mandena , IV.1960, Bosser 14548 ( P [ P00524465 ], P [ P06795979 ], TAN) ; Andohahela NP , 1.8 km N of Fanota, 24°46'S 46°52'E, 1.XI.2011, Hall et al. 53 ( K, TAN) .

Figures

Fig. 10. – Distribution maps. A. Panicum luridum Hack. (stars), P. manongarivense A. Camus (triangles), P. mitopus K. Schum. (circles) and P. novemnerve Stapf (squares); B. Panicum palackyanum A. Camus (stars), P. perrieri A. Camus (triangles), P. pleianthum Peter (circles) and P. spergulifolium A. Camus (squares).