Brachiaria bemarivensis A. Camus

Vorontsova, Maria S., 2022, Revision of some Malagasy forage grasses and their relatives within Brachiaria, Echinochloa, Moorochloa, and Urochloa, Candollea 77 (2), pp. 199-236 : 203-204

2. Brachiaria bemarivensis A. Camus in Bull. Soc. Bot. F rance 72: 369. 1925 (F ig. 2A–C).

Lectotypus (designated here): MADAGASCAR. Reg. Boeny [Prov. Mahajanga]: Haute Bemarivo , II.1907, Perrier de la Bâthie 11295 ( P [ P00450163 ]!; isolecto-: P [ P00450164 , P00450165 ]!) . Syntypus: ibid. loco, III.1907, Perrier de la Bâthie 11136 [as 11135] ( P [ P02040451 , P02040452 ]!) .

= Brachiaria bemarivensis subsp. ankarafantsikaensis A. Camus in Naturaliste Malgache 5: 147. 1953.

Lectotypus (designated here): MADAGASCAR. Reg. Boeny [Prov. Mahajanga]: Ankarafantsika près de Marovoay, III.1910, Perrier de la Bâthie 11223 ( P [ P00450162 ]!; isolecto-: P [ P02040448 , P00450167 , P00450168 ]!) . Syntypus: ibid. loco, III.1910, Perrier de la Bâthie 11225 ( P [ P00450160 , P00450161 , P00450166 ]!) .

= Acroceras parvulum A. Camus in Bull. Soc. Bot. F rance 101: 28. 1954, syn. nov. Holotypus: MADAGASCAR. Reg. Anosy [Prov. Toliara]: vallée du Mandrare , affl. de la Manampanihy, montagne au S de Tanandava , c. 500 m, III.1947, Humbert 20486 ( P [ P00450108 ]!) .

= Brachiaria benoistii A. Camus in Bull. Soc. Bot. F rance 101: 28. 1954. Lectotypus (designated here): MADAGASCAR. Reg. Atsinanana [Prov. Fianarantsoa]: env. d’Ambila, 17.III.1951, Benoist 813 ( P [ P00450169 ]!). Syntypus: i b i d. l o c o, 4.V. 1928, Decary 6383 ( P [ P00450170 !]) .

Mat-forming annual to short-lived stoloniferous perennial, prostrate with ascending flowering culms, to 0.6 m high, culms branched, rooting at lower nodes, glabrous. Leaf sheath sparsely hirsute, sometimes with bulbous-based trichomes towards apex. Ligule a lacerate ciliolate membrane. Leaf blade ovate to elliptic, membranous, 1–7 × 0.3–1 cm, often tinged with purple, glabrous to sparsely hirsute on both sides, sometimes with bulbous-based trichomes at base. Inflorescence racemose, slender, open, 5–12 cm long. Racemes 1– 10, 2–6 cm long, decreasing in length upwards, lowermost raceme roughly equal to inflorescence axis in length, on a common axis 0–7 cm long, sometimes with secondary branches, rhachis narrow, scaberulous, spikelets widely spaced paired, sessile and shortly pedicelled in each pair. Spikelets elliptic, apically rounded, 1.7 –2.3 mm long, whiteish, sometimes tinged with purple. Lower glume ½–⅔ as long as spikelet, membranous, obtuse to acute, 3-veined, glabrous or with shiny elongated prickle hairs, with fine white trichomes at apex, orientation relative to rhachis variable. Upper glume as long as spikelet, membranous, 5-veined, glabrous or with shiny elongated pricke hairs, detaching early. Lower floret male, palea ½ as long as lemma, anthers 3, 0.7 mm long. Lower lemma membranous, 5-veined, glabrous or with shiny elongated prickle hairs. Upper lemma rounded, smooth, shiny, pale becoming brown at maturity, with a green apical crest.

Distribution and ecology. – Common across Madagascar except the arid west and southwest, in the shade, forest edges, and forest understory, on dunes, sand, rocks, and roadsides, at elevations of 0–1600 m (F ig. 1).

Notes. – This attractive, fragile creeping plant with membranous leaf blades forms common ground cover across much of Madagascar. Young foliage is often tinged with red. Plant size, leaf width, and inflorescence size vary considerably.

It seems that environmental stress can result in culms with a single raceme only, and these have been described as Brachiaria benoistii A. Camus and Acroceras parvulum A. Camus. These collections have a single main inflorescence axis and poorly developed racemes, and have been collected from the east coast. These are not recognised here as a distinct taxon because no differences other than the inflorescence structure have been observed.

In the protologue of Brachiaria bemarivensis, Camus cites two collection numbers from forests in Bemarivo: Perrier de la Bâthie 11135 and 11295. Perrier de la Bâthie 11135 is almost certainly a transcription error for 11136 corrected here: the handwritten numbers 5 and 6 appear similar on the sheets, and 11135 is a collection of Schizachyrium Nees. The chosen lectotype is the best quality sheet from the collection that lacks ambiguity. The respective lectotypes designated here for Brachiaria bemarivensis subsp. ankarafantsikaensis A. Camus [P00450163] and B. benoistii [P00450162] represent the best preserved material annotated by Camus.

The name “ Brachiaria bemarivensis var. benoistii (A. Camus) Bosser ” appears on some herbarium sheets held at P and annotated by Bosser (e.g. Benoist 813, P [P00450169]) but this name does not appear to have been published and is therefore an invalid name (nomen nudum in sched.).

Selected specimens examined. – MADAGASCAR. Reg. Amoron’i Mania [Prov. Fianarantsoa]: Itremo , Andohatanimena , 19.II.2014, Nanjarisoa et al. 147 ( K, TAN) . Reg. Analamanga [Prov. Antananarivo]: Anjozorobe , Analabe, III.1952, Bosser 2408 ( P) ; Tampoketsa d’Ankazobe , III.1962, Bosser 15985 ( P) ; Belobaka , Analandraisoa , forêt d’Analandraisoa , IV.1963, Bosser 17650 ( P) . Reg. Analanjirofo [Prov. Toamasina]: F enoarivo Est, XI.1954, Bosser & Descoings 78 ( P) ; Mahavelona , XII.1962, Bosser 16869 ( P) ; Maroantsetra , Nosy Mangabe , V.1988, Schatz et al. 2325 ( MO, P, TAN) . Reg. Anosy [Prov. Toliara]: Beroroha , vallée du Mandrare, affl. de la Manampanihy, S de Tanandava, 11.III.1947, Humbert 71 ( P) ; Taolagnaro , Mahatalaky . Sainte Luce, 23.I.2012, Rakotonirina et al. 741 ( P) . Reg. Atsimo-Andrefana [Prov. Toliara]: Sakaraha , forêt du Zombitsy , III.1964, Bosser 19375 ( P, TAN) . Reg. Betsiboka [Prov. Mahajunga]: env. de Maevatanana, III.1900, Perrier de la Bâthie 1032 ( P) . Reg. Boeny [Prov. Mahajunga]: Ankarafantsika National Park office , 14.II.2017, Vorontsova & DuncanưRice 2090 ( K, P, TAN) . Reg. AIANA [Prov. Antsiranana]: vallée de l’Ifasy en aval d’Anaborano , 31.III.1951, Humbert & Capuron 25898 ( K, P) ; RS Manongarivo, Bekolosy, near village of Ambalafary , 12.III.1993, Malcomber et al. 2234 ( MO, P) ; ibid. loco, 12.V.2014, Vorontsova & Onjalalaina 1470 ( P, TAN) . Reg. Ihorombe [Prov. Fianarantsoa]: plateaux et vallées de l’Isalo , 29.I.1955, Humbert 29811 ( K, P) . Reg. Fitovinany [Prov. Fianarantsoa]: env. d’Ambila , 17.III.1951, Benoist 813 ( P) .