Urochloa maxima (Jacq.) R.D. Webster, Austral. Paniceae (Poaceae): 241. 1987

Vorontsova, Maria S., 2018, Revision of the group previously known as Panicum L. (Poaceae: Panicoideae) in Madagascar, Candollea 73 (2), pp. 143-186 : 183-184

32. Urochloa maxima (Jacq.) R.D. Webster, Austral. Paniceae (Poaceae): 241. 1987 .

≡ Panicum maximum Jacq., Icon. Pl. Rar. [Jacquin] 1: 2, tab. 13. 1781 .

≡ Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs in Austrobaileya 6: 572. 2003.

Holotypus: FRANCE. Guadeloupe: sine loco, Jacquin s.n. ( W [ W0011326 ] image seen; isotype: BM image seen) .

= Panicum mananarense A. Camus in Notul. Syst. (Paris) 15: 412. 1959 . Lectotypus (designated here): MADAGASCAR. Prov. Toliara: basse vallée de la Mananara , affluent du Mandrare , 50– 150 m, 1–2.III.1955, Humbert & Capuron 29160 ( P [ P00450288 ]!; isolectotype: P [ P00450287 , P00450289 ]!), syn. nov.

= Panicum maximum var. effusum A. Camus in Notul. Syst. (Paris) 15: 413. 1959 . Lectotypus (designated here): MADAGASCAR. Prov. Toliara: env. d’Antanimoro , 30–35 km au N vers Ambia, 200–500 m, 6–9.II.1955, Humbert & Capuron 28804 ( P [ P00450292 ]!; isolectotype: K [ K001096176 ]!, P [ P00450290 , P00450291 ]!) , syn. nov.

= Panicum mahafalense A. Camus in Bull. Soc. Bot. France 72: 620. 1925. Holotypus: MADAGASCAR. Prov. Toliara: dunes de Tsimanampetsotsa, côte Mahafaly , VI.1910, Perrier de la Bâthie 11181 ( P [ P00450235 ]!) , syn. nov.

Erect tufted perennial, the habit variable, 0.5–2 m tall, the culms and nodes glabrous to pilose. Leaf sheaths glabrous to pilose. Ligule a ciliolate membrane. Leaf blades linear-lanceolate, flat, chartaceous, 15–100 × 10–35 cm, drying yellow-green, glabrous to pilose on both sides. Panicles terminal, fully exserted 15–70 cm long, oblong or pyramidal, the branches ascending to spreading, glabrous or sometimes sparsely pilose, the lowermost branches arranged in a whorl. Spikelets oblong, apically obtuse, 3–4.5 mm long, green to olive or purple, never gaping open. Lower glume ¼–1/3 as long as the spikelet, membranous, obtuse to acute, 3-veined, glabrous or finely pubescent. Upper glume as long as the spikelet, herbaceous, 5-veined, glabrous or finely pubescent. Lower floret male, with palea. Lower lemma herbaceous, 5-veined, glabrous or finely pubescent. Upper lemma with a pronounced rugose surface visible with a hand lens.

Distribution and ecology. – A pantropical weed of global importance including La Réunion, Mauritius, and Rodrigues. Common throughout Madagascar usually in severely disturbed habitats, 0–1500 m ( Fig. 16B ).

Notes. – Likely the most common and the most abundant grass in Madagascar, Urochloa maxima is commonly seen by the roadside and in secondary vegetation formations throughout the island. It is also found in ecosystems that are otherwise natural. The limited herbarium collections cited here do not begin to represent the real distribution of Urochloa maxima across Madagascar. The common assumption that this plant is a weedy introduction from tropical Africa may not be true: its distribution and variability suggests it could be part of the island’s natural pioneer flora.

This is Madagascar’s only species of Panicum s.l. with a rugose upper floret. BOSSER (1969) considered P. mahafalense , also with a rugose upper floret, to be an endemic species different from Urochloa maxima by its pubescent spikelets and a smaller habit. Panicum mahafalense is here placed in synonymy under Urochloa maxima . Pubescent spikelets are in fact a common variant of the reputedly variable U. maxima worldwide (CLAYTON & RENVOIZE, 1982) and no difference could be confirmed in plant size.

The type collection of Panicum mananarense is cited as “ Humbert & Capuron 29168” in the protologue, which is almost certainly an error for Humbert & Capuron 29160; the lectotype sheet is chosen for its superior flowering material annotated by A. Camus. The lectotype sheet of P. maximum var. effusum is also chosen for its superior flowering material annotated by A. Camus. The holotype number of P. mahafalense A. Camus is cited as 11101 in the protologue, an error for 11181.

This species is illustrated in BOSSER (1969: Fig. 118).

Additional material examined. – MADAGASCAR. Prov. Antananarivo: central Madagascar , X.1881, Baron 525 ( K [ K000805511 ]) ; ibid.loco, X.1882, Baron 1996 ( K [ K000805513 ], P [ P02394631 ]) ; Imerina, 1881, Cowan s.n. ( P [ P02394616 ]) ; Antananarivo, 15.I.1975, Croat 28463 ( K [ K000805502 ], P [ P02394663 ]) ; ibid. loco, 24.IV.1921, Decary 215 ( P [ P02394635 ]) ; ibid. loco, 3.V.1943, Decary 19379 ( K [ K000805507 ], P [ P02394653 ]) ; Tsimbazaza, 20.II.1984, Dorr 2819 ( K [ K000805500 ], P [ P02394660 ]) ; région de Tananarive , 15.XII.1966, Granier & Delhaye 16989 ( P [ P02394676 ]) ; Tsimbazaza, V.1935, Herb. Jard. Bot. Tan. 3248 ( P [ P02394460 ]) ; ferme vétérinaire de Kianjasoa , Herb. Jard. Bot. Tan. 32436 ( P [ P02394632 ]) ; ibid. loco, Herb. Jard. Bot.Tan. 32439 ( P [ P02394462 ]) ; Nanisana, 21.III.1933, Herb. Jard. Bot. Tan. 32486 ( P [ P02394633 ]) ; ibid. loco, 10.IV.1933, Herb. Jard. Bot. Tan. 32493 ( P [ P02394461 ]) ; Ambalavao, 14.X.1970, Keraudren-Aymonin & Aymonin 24622 ( P [ P02394674 ]) ; cour des subsistences militaires à Analakely , 25.IV.1907, Rotereau s.n. ( P [ P02726810 ]) ; Ambohimanga, Waterlot 113 ( P [ P02394617 ]) ; Antananarivo, Waterlot s.n. ( P [ P02394618 ]) . Prov. Antsiranana: Ambanja station I.F.C.C ., 18.VI.1962, Anon. 54 ( P [ P02394647 ]) ; env. de Diego-Suarez , April, Bernier 18 ( G, P [ P02726865 ]) ; Nosy Be, VI.1847, Boivin 1964 ( P [ P02394638 ]) ; Port Leven, III.1849, Boivin 2268 ( P [ P02394637 ]) ; Nosy Be, Boivin s.n. ( P [ P02394636 ]) ; ibid. loco, Fournier s.n. ( P [ P02394610 ]) ; Ankarana, XII.1937, Humbert 18854 ( P [ P02394641 ]) ; vallée de l’Antsahabe , 10.III.1949, Humbert 23317 ( G, P [ P03182733 ]) ; Daraina, forêt de Bekaraoka , 13°06'23"S 49°42'49"E, 9.I.2005, Nusbaumer & Ranirison 1379 ( G [ G00019420 ], P [ P02309331 ]) ; Daraina, forêt d’Antsahabe , 13°12'38"S 49°33'29"E, 29.X.2005, Rakotondrafara et al. 331 ( G [ G00096371 ], P [ P02373639 ]) . Prov. Fianarantsoa: Ranomafana , 18.V.1951, Bosser 353 ( P [ P06768705 ]) ; Mananjary, III.1909, Geay 7149 ( P [ P02394643 ]) ; ibid. loco, III.1909, Geay 7253 ( P [ P02394646 ]) ; ibid. loco, III.1909, Geay 7609 ( P [ P02394627 ]) ; Isalo, haute vallée de la Mania , 29.I.1955, Humbert 28777 ( G, K [ K000805498 ], P [ P03182700 ]) ; Isalo NP , Namaza , 22°32'23"S 45°22'53"E, 18.XII.2013, Vorontsova et al. 1331 ( TAN) . Prov. Mahajanga: Beanka , 17°52'36"S 044°28'35"E, 27.I.2012, Bolliger et al. 153 ( G [ G00340170 ]) ; Bevendro mountain, 25.XI.1932, Leandri 634 ( P [ P02394614 ]) ; Maevatanana, Ikopa , VI.1898, Perrier de la Bâthie 224a ( P [ P02394648 ]) ; “ Suberbieville ”, V.1897, Perrier de la Bâthie 224b ( P [ P02394658 ]) ; Ambongo, 1932, Perrier de la Bâthie 11142 ( P [ P02394656 ]) ; env. de Madirovalo , IV.1910, Perrier de la Bâthie 11232 ( P [ P02394655 ]) . Prov. Toamasina: Tamatave , VII.1903, Bernard s.n. ( P [ P02394453 ]) ; Sainte Marie island, V.1947, Boivin 1621 ( P [ P02394642 ]) ; Ilaka-Est, XII.1962, Bosser 16873 ( P [ P02394630 ]) ; Imerimandroso, 3.VII.1921, Decary 184 ( P [ P02394615 ]) ; Ivoloina, Dequaire 27643 ( P [ P02394673 ]) ; lac Alaotra , Herb. Jard. Bot. Tan. 3496 ( P [ P02394649 ]) ; Ambatondrazaka, 7.III.1932, Herb. Jard.Bot.Tan. 324128 ( P [ P02394457 ]) ; ibid. loco, 30.IX.1932, Herb. Jard. Bot. Tan. 324133 ( P [ P02394458 ]) ; Tamatave, III.1932, Herb. Jard. Bot.Tan. 324170 ( P [ P02394459 ]) ; Ambatondrazaka, III.1932, Herb. Jard. Bot. Tan. 324154 ( P [ P02394455 ]) ; massif de l’Ivakoany , XI.1933, Humbert 12257 [a] ( P [ P02394634 ]) ; Manakambahiny Est, 24.XII.1962, Rakotovao 12369 ( P [ P02394659 ]) ; côteaux de l’Ivoloina , 20.IX.1912, Viguier & Humbert 204 ( P [ P02394609 ]) . Prov. Toliara: Sakamalio valley, 17.I.1913, Afzelius s.n. ( NY) ; Ambovombe, XI.1956, Bosser 10132 ( TAN) ; Ifotaka, III.1960, Bosser 14606 ( P [ P02726845 ]) ; 23–28 km W of Manambaro, 21.II.1975, Croat 31983 ( P [ P02394664 ]) ; Ambovombe, 8.IV.1924, Decary 2595 ( P [ P02394624 ]) ; Mahabo, 1952, Dequaire 27120 ( P [ P02394668 ]) ; bas Mangoky, V.1955, Descoings 356 ( P [ P02726857 ]) ; ibid. loco, III.1955, Descoings 396 ( P [ P02394665 ]) ; delta de la Linta, 24.VIII.1928, Humbert & Swingle 5443 ( P [ P02394626 ]) ; vallée moyenne du Mandrare près d’Anadabolava , XII.1933, Humbert 12412 ( P [ P02394666 ]) ; ibid. loco, XII.1933, Humbert 12542 ( P [ P02394654 ]) ; Mt Morahariva, XII.1933, Humbert 13093 ( P [ P02394640 , P02394651 ]) ; entre l’Andohahela et l’Elakelaka , I.1934, Humbert 13960 ( P [ P02394620 ]) ; col d’Ambato et pentes orientales du Vohipaly , II.1934, Humbert 14151 ( K [ K000805506 ], P [ P02394639 ]) ; forêt d’Analavelona , III.1934, Humbert 14261 ( P [ P02394670 ]) ; env. de Manombo , forêt d’Isonto 28.I.1947, Humbert s.n. ( P [ P03182756 ]) ; ibid. loco, 28.I.1947, Humbert s.n. ( P [ P02394623 ]) ; Mahaboboka, 27.II.1964, Peltier & Peltier 4970 bis ( P [ P02309298 ]) ; Beza Mahafaly, 23°39'S 44°38'E, 31.IV.1987, Phillipson 1749 ( K [ K000805501 ], P [ P02309307 ]) ; Ranobe forest, 23°00'22"S 23°00' 22"E, 13.III.2006, Phillipson et al. 5849 ( G, P [ P02625311 ]) ; région Ihotry , 28.IV.1995, Ranarijaona 72 ( P [ P02373638 ]) ; Soalary, 21.III.1953, Ravelonanahay 4947 ( P [ P03182696 ]) ; Ampandrandava, XI.1942, Seyrig 351 ( P [ P02394657 ]) ; Belamoty; 25°02'57"S 44°23'27"E, 25.IV.2014, Vorontsova et al. 1406 ( TAN) . Sine loco: 8.III.1945, Cours 2724 ( P [ P03182697 ]) ; Cours s.n. ( P [ P02394672 ]) ; Cours s.n. ( P [ P02394671 ]) ; Herb. Jard.Bot.Tan. 892 ( P [ P02394628 ]) ; Herb. Jard.Bot. Tan. 893 ( P [ P02394625 ]) ; 1896, Husnot s.n. ( P [ P03183500 ]) ; 1896, Husnot s.n. ( P [ P03183501 , P02394454 ]) ; 1887, Myre de Villers s.n. ( P [ P02394661 ]) ; I.1934, Perrier de la Bâthie s.n. ( P [ P02394677 ]) .

Figures

Fig. 16. – Distribution maps. A. Panicum subalbidum Kunth (stars), P. subhystrix A. Camus (triangles), P. trichocladum K. Schum. (circles) and P. voeltzkowii Mez (squares); B. Panicum vohitrense A. Camus (stars), Trichanthecium brazzavillense (Franch.) Zuloaga & Morrone (triangles), T. parvifolium (Lam.) Zuloaga & Morrone (circles) and Urochloa maxima (Jacq.) R.D. Webster (squares).