Disakisperma obtusiflorum (Hochst.) P. M. Peterson & N. Snow, Annals Bot. 109: 1327. 2012.

Snow, Neil, Peterson, Paul M. & Romaschenko, Konstantin, 2013, Systematics of Disakisperma (Poaceae, Chloridoideae, Chlorideae), PhytoKeys 26, pp. 21-70 : 48-49

Disakisperma obtusiflorum (Hochst.) P. M. Peterson & N. Snow, Annals Bot. 109: 1327. 2012. Figure 4A-O

Leptochloa obtusiflora Hochst. Flora 38: 203. 1855. Eleusine obtusiflora (Hochst.) Blatt., Rec. Bot. Surv. India 8: 505. 1936.

Type.

ETHIOPIA, W. Schimper in Herb. Buchinger 1204 (holotype: STR; isotypes: B!, P!, S! co-mounted with a specimen of Trigonochloa uniflora (Hochst. ex A. Rich) P.M. Peterson & N. Snow).

Description.

Perennials. Culms 45-200 cm tall, 1.2-5.0 mm wide at base, round, erect to sprawling, from fibrous or knotted root crowns sometimes bearing short cataphylls (rhizomatous in the opinion of some, e.g. Chiovenda 2585 [US]), often branching (sometimes abundantly so; e.g., Glover & Gilliland 298 [US]); nodes glabrous; internodes (1.5-) 3-35 cm long, soft, hollow. Leaf sheaths longer or shorter than the internodes, mostly round, glabrous or sparsely hairy near apex, the margins glabrous; collar tan or maroon; ligules 1.7-2.2 mm long, membranous, often somewhat lacerate, apically truncate and erose; blades 7-37 cm long, up to 12.5 mm wide, cauline, linear, flat but drying involute, mostly glabrous but sometimes sparsely pilose at the base of blade to minutely but densely scabrous above, nearly glabrous to minutely but densely scabrous below, not disarticulating at base, midrib prominent. Panicles 28-65 cm long, 3-8 (-12) cm wide, exserted at maturity; branches (4-) 9-18, (2.5-) 9-13 cm long, alternate along the rachis, steeply ascending to erect, somewhat flexuous, minutely scabrous, the axils shortly pilose. Spikelets 3.7-6.5 (-8.5) mm long with 5-10 (-15)-flowered, pedicels to 1.2 mm long, imbricate about halfway near base of branches to tightly at branch tips; callus glabrous; lower glumes 1.5-2.9 mm long, membranous, narrowly ovate or occasionally ovate, scabrous on midnerve, acute; upper glumes 1.8-2.9 mm long, membranous, ovate, scabrous on midnerve, acute; lemmas 2.2-2.8 (-3.0) mm long, 3-nerved (rarely 4-5-nerved above base), membranous, ovate, light brown, green, or maroon, the lateral nerves distinctly raised and usually bright green, sericeous along the lower ¾ of the nerves and between the nerves, the hair tips clavate or clavicorniculate, apex obtuse and sometimes bifid; paleas 2.0-2.3 mm long, membranous, ovate, sparsely short pubsecent on lower half between nerves or nearly glabrous, apex broadly acute. Anthers ca 0.7 mm long, yellow. Lodicules 0.2-0.3 mm long. Caryopses 1.4-1.5 mm long, 0.7-0.8 mm wide.

Leaf anatomy. Midribs are always present and the diameter of primary bundles exceeds that of the secondaries.

Stem anatomy. Culms with outer (subepidermal) and inner (cortical) sclerenchymatous rings. Other details uncertain [Voucher: Harris & Tadres 2151 (MO)].

Chromosome number. n = 20 ( Ammal 1955; voucher not seen).

Phenology.

Flowering July through December.

Distribution.

Native: India west to Saudia Arabia, Yemen and Somalia; south through Tanzania, and Angola; in a variety of semi-open or disturbed habitats in rocky areas or sandy to heavy soils, from sea level to 1900 m. (TDWG: ANG, BUR, CON, ERI, ETH, KEN, SAU, SOM, SUD, TAN, UGA, YEM. Non-native: IND (see comment below).

Conservation status.

Least Concern ( IUCN 2010).

Etymology.

The epithet probably refers to the obtuse lemma apex.

Vernacular name.

North African sprangletop. Somalia: Buldorle, Rareh. Suggested: African Jacobsgrass.

Comments.

Herbarium specimens (and label descriptions) often indicate the panicle as nodding or pendulous, which contrasts with the more nearly erect panicle of the related Disakisperma eleusine , which Disakisperma obtusiflorum closely resembles, but which occurs farther. The collection of Jackson 3977 (K)differs in its short stature, profuse branching, and short panicles that bear only 1-2 branches, which may reflect local grazing selection. Over ninety collections have been seen from Uganda, although not all are reported below.

The species evidently may occur in nearly pure stands and is known in abandoned cultivated areas. The label of Greenway 2213 (US) indicates the species is "A useless fodder as it causes dysentery in cattle according to the Wapares." Boonman (1993) reports that Disakisperma obtusiflorum is a potential species for reseeding denuded pasture.

Hooker (1896) clearly included Poa maysorensis Rottler ex Hook. f., nom. inval., in synonymy of Disakisperma obtusiflorum , andmerely cited the Rottler name as being in manuscript. Hooker (1896) suggested that the presence of the species in southern India in Kochi ( “Cochin”) was an introduction due to heavy trade between that port and Africa.

Specimens examined.

Angola. Loanda: Maianga d’El Rei, Welwitsch 7282 (BM); On the rocky banks of Riv. Long at Capolo, Gossweiler 8281 (K, US). Burundi. Bubanza: Rugombo, Reekmans 6486 (B, MO, PRE). Bujumbura: Gitaza, Reekmans 4010 (MO). Democratic Republic of the Congo. Sud-Kivu. Kabare, Bequaert 5348 (K); Parq. Nat. Albert [=Virunga Nat. Park], Rurindi, Lebrun 7943 (K, M, MO) & Rurindi, Lebrun 7784 (MO, NY). Orientale. Terr. Mahagi, Plaine Iswa-village Awora, Taton 1246 (MO). Eritrea. Northen Red Sea: Lungo il Torrente Haddas, Pappi 2585 (G, MO, P, US). Ethiopia. Harrar: 35 km along the road from Dire Dawa to Erer Gota, De Wilde 6449 (M, MO). Gamu Gofa: 72 km S of Soddu on road to Arba Minch, 50 km from Arba Minch, Gilbert et al. 8860 (K). India. Kerala: Cochin (=Kochi), Rottler s.n. (K). Tamil Nadu: Coimbatore, Narayana 1929 (NY); On the way to Areakhalti, Raju & Napanatham 4763 (K). Madras [Chennai], Janaki Ammal 1154a (K); Masanagudi, The Niligris, Barber 2656 (US). Kenya. Coast Province, Kwale, near Taru, between Samburu & Mackinnon Rd., Drummond & Hemsley 4192 (B); Tsavo N.P. West, 7 km S of Mtito Andei, Belsky 527 (BH); Kitovo, Taveta, Nye 42 (BM); Mtwapa, Thorold 2002 (K); Vipingo 20 mi N of Mombasa, Verdcourt 1101 (K, MO). Mombasa, Napier 6370 (K, PRE); Tsavo N.P. East, Greenway & Kanuri 12836 (K, P); Tsavo N.P., N end, Heady 1759 (UC); Gazi, along coast, Heady 1376 (MO, UC); Galole [=Hola], Makin 128 (P). Eastern Province, Kiboko Range Research Stn., near Makindu, Ndegwa 579 (MO); Near Makindu Riv.,... Kiboko Range Research Stn., Ndegwa 474 (MO); Kibwezi, McCallum Webster K164 (K); Kilifi Distr., N of & just below Jilore Forest Station, Perdue & Kibuwa 10124 (K, NA); Maktau, Hitchcock 24697 (K, US). Nairobi Province, Nairobi, Hitchcock 24822 (US); Nairobi, Lyne Watt 18 (US). Nyanza Province, Kisumu, Hitchcock 24865 (K, US). Rift Valley Province, K1, Mathew’s Range [=Lenkiyio Hills], Gachathi 440 (B); Southern Turkana at Namorutung’a near Lokori, Mwangangi & Gwynne 1161 (MO); Kitale grass nursery, Heady 1474 (MO, UC); Turkana Distr., Oropoi Valley, Liebenberg 27 (MICH, PRE, US). Saudi Arabia. Wadi Maraba, foot of Raidah Escarpment, Collenette 8764 (K); Jizan-Abha Rd., ca. 20 km from Abha, Chandhanj 7262 (K). Somalia. Government House grounds, Hargeisa, Glover & Gilliland 17 (BM, K); Within a radius of ca. 5 mi of the Hargeisa Stn, Farquharson 29 (K); 29 km SW on coast road from Mogadishu airport, then inland 2.5 km, Kuchar 17708 (K); Burran, Erigavo Distr., McKinnon S122 (BM, US); Between Wasdere & Walwal, Glover & Gilliland 398 (BM, P, US); Wobleh, Gillett 4584 (K, P); Tugdheer region, 6 km NW of Borao, Hansen & Heemstra 6105 (K). Hargesia, Gillett 4059 (K, P, S). Sudan. Kurdufan Province, Rahad, 1 hour S of J. Hadadiad, Taganor Wilderness, Michelmore s.n. (K). Red Sea Province, Slopes Jebel Hamoyet, Red Sea Hills, Jackson 3977 (K). Tanzania. Arusha Region, Lake Manyara N.P., Near Mbagaya Riv.-Ndabash, Greenway & Kanuri 11280 (K, PRE); Serengeti N.P., Serengeti Research Institute, Belsky 144 (BH, MO). Kilamanjaro Region, Moshi, GB Wallace 1190 (NY); Mwanga District, Peterson, Soreng & Romaschenko 24198 (DSM, US). Lindi Region, Lutamba-See, 40 km westlich Lindi, Schlieben 5945 (M, S); Lindi, H J Schlieben 5945 (M). Manyara Region, Mbagaya Riv.-Ndabash, Lake Manyara N.P., Greenway & Kanuri 11280 (PRE). Mara Region, T1, Klein’s Camp to Bologonja Riv., Greenway 10666 (K); Musoma Distr., Seronera, Greenway 9971 (K, US). Moshi Region, Pangani Distr., Kikokwe area, Bond 84 (P); Pangani Distr., Jassini in sandy hollow, Milne-Redhead & Taylor 7297 (K, US); Moshi, Hitchcock 24557 (US); Vicinity of Moshi, Kiboscho Rd., Piemeisel & Kephart 405 (US); Moshi Town, B Mhoro 1868 (MO); Moshi Kilimanjaro, Shantz 791 (K, US). Mwanza Region, Lake Prov., Nyegezi, Bunegeji Chiefdom, Tanner 1060 (K, MICH, NY, UC). Tanga/Kilimajaro Region, Pandani River, Peterson, Soreng & Romachenko 24243 (DSM, US). Tanga Region, Korogwe Distr., Magunga Estate, Faulkner 961 (A, K); 5 km W of Tonibombo, Peterson, Soreng & Romaschenko 24211 (DSM, US); Muheza, Hitchcock 24540 (US); Mkaramo, Mkwaja Subchiefdom, Pangani Distr., Tanner 2346 (K, NY, UC). Zanzibar Central/South Province, Kisuani [Airport], Greenway 2213 (K, US). Unknown Province: T3, Kwamarukanga, Magogo 344 (K); Saira, HG Faulkner 3775 (K, P). Uganda. Central Region, Mengo-Kisenyi, Kyadondo, W. Mengo District, Rwaburindore 2134 (MO). Eastern Region, Buyonjo, Lake side, Busogo, Maitland 1100 (US); Serere, at Robori, Maitland 1345 (B, K, US). Western Region, Katwe Ruwenzori, Maitland 963 (B); Butiala, Lake Albert, Thomas 4086 (K); Mohokya Toro, AS Thomas 2757 (K). Yemen. Between Beni Omer & Barakain, Hoogariah, Wood 1407 (BM, K); Between Taiz & Sharab (Roona), Wood Y/75/966 (BM); Hadia, Wood Y/75/797 (BM).

Figures

Figure 4. Disakisperma obtusiflorum (Hochst.) P. M. Peterson & N. Snow A habit B culm andinflorescence C sheath, ligule, and blade, ventral view D branch of inflorescence E spikelet F floret, ventral view G lower glume H upper glume I palea, dorsal view I lemma J lodicules and pistil enclosed in palea K lodicules and stamens enclosed in palea L palea, dorsal view M lodicules and stamens N caryopsis, dorsal view O caryopsis, ventral view. Drawn from Shantz 791 (US).