Cenchrus pedicellatus (Trin.) Morrone in Chemisquy et al., Ann. Bot. (Oxford) 106: 128. 2010.

Wessapak, Paweena, Ngernsaengsaruay, Chatchai & Duangjai, Suthee, 2023, A taxonomic revision of Cenchrus L. (Poaceae) in Thailand, with lectotypification of Pennisetum macrostachyum Benth., PhytoKeys 234, pp. 1-33 : 1

5. Cenchrus pedicellatus (Trin.) Morrone in Chemisquy et al., Ann. Bot. (Oxford) 106: 128. 2010.

Figs 8 , 9

Pennisetum pedicellatum Trin., Mém. Acad. Imp. Sci. Saint-Pétersbourg, Sér. 6, Sci. Math., Seconde Pt. Sci. Nat. 3(2): 184. 1834. Basionym.

= Pennisetum lanuginosum Hochst., Flora 27: 252. 1844. Type: Sudan, Oct 1839, C. G. T. Kotschy 394 (lectotype, designated by Gutiérrez 2015, pg. 164: TUB [TUB018061-cb006519] n.v.; isolectotypes: BM [BM000923370!], K [K000281241!], W [W0000305, W18890244992] seen on digital images).

= Pennisetum amoenum Hochst. ex A. Rich., Tent. Fl. Abyss. 2: 386. 1850. Type: Ethiopia, Oct 1839, G. H. W. Schimper 641 (lectotype, designated by Gutiérrez and Morrone 2012, pg. 267: P [P03471044!]; isolectotypes: B [B100167868] seen on digital image, BM [BM000923371!], W [W18890244973] seen on digital image).

Type.

Cape Verde Islands, St. Iaga , D. Peters s.n. (holotype: LE [Herb. Trinius 1102.1] n.v.) .

Description.

Annual, tufted. Culms erect or ascending, 0.5-2 m high; nodes glabrous; internodes subterete, sometimes slightly flattened, 5.5-30 cm long, 1.5-9 mm in diam., glabrous. Leaf sheaths 7-13 mm long, margins with hairs or tubercle-base hairs, glabrous. Ligules ciliate membrane, 2-4 mm long. Collar glabrous. Leaf blades linear, 20-50 × 0.5-1.7 cm, apex acute, base rounded with tubercle-base hairs, margins scabrous, chartaceous, hairy on both surfaces. Inflorescence spiciform panicle, 22-35 × 2.5-3 cm (including bristles); central axis with shortly decurrent ribs, 11-19 cm long, scabrous or pubescent; peduncle terete, 10-20 cm long, villose or scabrous; short racemes along central axis; raceme with 2-4 spikelets in cluster, one sessile and the other pedicelled, sessile spikelet smaller than pedicelled spikelet; pedicels 1-3 mm long, hairy; subtended by the involucre bristles. Involucre composed of outer and inner circles, numerous and free at base, outer circle shorter than inner circle; outer involucre 2-5 mm long; inner involucre 1-2 cm long, one conspicuous longest bristle 1.6-2.5 cm long, antrorsely scabrous and woolly hairs; involucre falling with spikelets; stipe (raceme-based) absent. Spikelets dorsally compressed, lanceolate, 3.5-5 × 0.8-1.4 mm. Lower glume lanceolate or lanceolate-elliptic, 1-2.5 × 0.5-1 mm, apex bifid, hyaline, pubescent, nerveless or 1-nerved. Upper glume lanceolate or elliptic, 3.5-5 × 1-1.3 mm, apex acuminate, cuspidate or mucronate, membranous, glabrous or scabrous, 5-nerved. Florets 2. Lower floret male. Lower lemma lanceolate, 3-4 × 0.8-1.2 mm, apex trifid, membranous, glabrous or scabrous, 5-nerved. Lower palea lanceolate or oblong-lanceolate, 3-4 × 0.4-0.6 mm, apex acute to acuminate, margins folded, membranous, glabrous, 2 or 3-nerved. Upper floret bisexual, caducous. Upper lemma lanceolate, 1.8-2.8 × 0.5-1 mm, apex obtuse with ciliate, coriaceous, glabrous, 3-obscure or 5-nerved. Upper palea lanceolate, 1.8-2.8 × 0.5-1 mm, apex obtuse with ciliate, coriaceous, glabrous, nerveless. Lodicules absent. Stamens 3; filament 1.5-2 mm long; anther yellow, 1.5-2.2 mm long. Pistil ovary oblong or elliptic, 0.4-0.8 × 0.1-0.2 mm; style 2; stigma plumose, 2.8-4 mm long. Caryopsis ellipsoid, 1.3-2 × 0.6-1 mm.

Distribution.

Originally form Tropical Africa, India and Macronesia and introduced elsewhere.

Distribution in Thailand.

NORTHERN: Chiang Mai (Mae Rim, Doi Suthep-Pui, Doi Saket, Mae Chaem, Samoeng, Mueang Chiang Mai), Lamphun (Doi Khun Tan), Tak; NORTH-EASTERN: Loei (Phu Luang, Phu Ruea, Phu Kradueng), Udon Thani (Ban Dung, Phu Kao), Nong Khai, Maha Sarakham, Khon Kaen (Phu Wiang, Tha Phra); EASTERN: Nakhon Ratchasima (Pak Thong Chai, Pak Chong), Buri Ram (Chaloem Phra Kiat), Si Sa Ket (Khao Phra Wihan), Ubon Ratchathani (Pha Taem, Phu Chong Na Yoi); SOUTH-WESTERN: Kanchanaburi (Thong Pha Phum); CENTRAL: Bangkok, Suphan Buri (Mueang Suphan Buri), Nakhon Nayok (Khao Yai), Samut Prakan (Phra Pradaeng); SOUTH-EASTERN: Prachin Buri (Khao Khiao), Chon Buri (Ko Si Chang, Sattahip), Sakaeo (Aranyaprathet).

Habitat and ecology.

In open areas by the roadside, open areas in disturbed or deciduous forest at elevations of 25-1100 m a.m.s.l. Flowering and fruiting from October to March.

Vernacular name.

Ya kha chon chop (หญ้าขจรจบ), Ya kha chon chop dok yai (หญ้าขจรจบดอกใหญ่); Annual kyasuwa grass, Deenanath grass, Dinanath grass, Hairy fountain grass (English).

Specimens examined.

Thailand. Bangkok: 16 Dec 1990, K. Larsen, S. S. Larsen, W. Nanakorn, W. Ueachirakan & P. Sirirugsa 42014 (AAU); Buri Ram: Chaloem Phra Kiat, Isan Khet, 21 Oct 2017, P. Wessapak 409 (BK); Chiang Mai: Doi Saket, Ban Pang Faen, 10 Dec 1998, F. Konta & S. Khao-Iam 4422 (BKF); Doi Suthep, 21 Oct 1987, J. F. Maxwell 87-1218 (AAU, BKF); Doi Suthep-Pui, 21 Nov 1996, S. K. Kafle 13 (CMUB); Mae Chaem, Ban Mae Wak, 19 Dec 1998, F. Konta, C. Phengklai & S. Khao-Iam 4813 (BKF); Mae Rim, 10 Feb 2006, C. Glamwaewwong 466 (QBG); Mueang Chiang Mai, 5 Dec 1989, C. Lek-korbkul 602 (CMUB); Samoeng, 21 Oct 2001, S. Laegaard 21763 (AAU, BKF, K, QBG); Chon Buri: Ko Si Chang, 29 Nov 1992, J. F. Maxwell 92-785 (CMUB, P); Sattahip, Thung Brong, 10 Jun 1971, J. F. Maxwell 71-416 (AAU, BK); Kanchanaburi: Thong Pha Phum, Pilok, 23 Oct 2004, S. Sirimongkol 166 (BKF); Khon Kaen: Phu Wiang, Khok Phu Ta Ka, 30 Nov 2003, C. Jaroenchai 36 (KKU); Tha Phra, 3 Nov 1971, T. Smitinand 11518 (BKF); Lamphun: Mae Tha, Doi Khun Tan, 18 Nov 1993, J. F. Maxwell 93-1376 (BKF, CMUB); Loei: Phu Kradueng, 25 Dec 2011, M. Norsaengsri & N. Tathana 8424 (QBG); Phu Luang, 19 Dec 2001, V. Chaemchumroon 1204 (BKF); Phu Ruea, 27 Nov 2005, C. Jaroenchai 243 (KKU); Maha Sarakham: 30 Oct 1965, S. Sutheesorn 705 (BK); Nakhon Nayok: Khao Yai, 13 Oct 1984, G. Murata, C. Phengklai, S. Mitsuta, H. Nagamasu & N. Nantasan T-52211 (BKF); ibid., 15 Oct 1984, G. Murata, C. Phengklai, S. Mitsuta, H. Nagamasu & N. Nantasen T-52591 (BKF); Nakhon Ratchasima: Pak Chong, 14 Jan 1965, Umpai 172 (BK); Pak Thong Chai, Nov 1970, Ch. Charoenpol, K. Larsen & E. Warncke 4535 (BKF, K); 9 Dec 1962, C. Phengklai 408 (BKF); 6 Nov 1963, T. Smitinand 8398 (BKF); Nong Khai: 10 Nov 1984, G. Murata, S. Mitsuta, T. Yahara, H. Nagamasu & N. Nantasen T-40452 (BKF); Prachin Buri: Mueang Prachin Buri, Khao Khiao, 25 Oct 2000, S. Watthana & T. Riyapun 963 (QBG); Sakaeo: Aranyaprathet, 20 Nov 1984, Chabeuf s.n. (P); Samut Prakan: Phra Pradaeng, Song Khanong, 25 Mar 2012, P. Wessapak & C. Ngernsaengsaruay 205 (BK); Si Sa Ket: Khao Phra Wihan, Pha Mo I Daeng, 21 Dec 2005, R. Pooma, K. Pattarahirankanok, S. Sirimongkol & K. Poopath 6002 (BKF); 10 Oct 1984, G. Murata, C. Phengklai, S. Mitsuta, H. Nagamasu & N. Nantasen T-38118 (BKF)]; Suphan Buri: Mueang Suphan Buri, Don Masang, 30 Dec 2016, P. Wessapak 352 (BK)]; Tak: Mae Sot-Umphang road, 23 Oct 1997, Anonymous s.n. (QBG); Ubon Ratchathani: Pha Taem, 28 Oct 2001, S. Laegaard, M. Norsaengsri, P. Pornpongrungrueng & S. Khoomkrathok 21857 (AAU, QBG); Phu Chong Na Yoi, Phalan Kong Kwian, 6 Nov 2010, P. Wessapak, Y. Buangam & W. Sareemongkonnimit 158 (BK); Udon Thani: Ban Dung, Ban Dung Yai, 4 Dec 2008, M. Norsaengsri 4561 (QBG); Phu Kao, Non Sung, 3 Jan 1968, K. Bunchuai 1519 (BKF, C).

Note.

This species has been used for improving pasture quality, in soil remediation and erosion control ( Asmare et al. 2016; Umer et al. 2019; Kumar and Fulekar 2022). It was introduced to Thailand from India for forage. At present, it has become naturalised as a weed and is distributed to almost all Thai floristic regions. Cenchrus pedicellatus is a close relative of C. setosus , but differs in terms of having a pedicelled spikelet, while C. setosus only has one sessile spikelet. Furthermore, its hairs on bristles are usually fluffier than the latter.

Figures

Figure 8. Cenchrus pedicellatus (Trin.) Morrone A habit B ligule C spikelet with involucre D pedicelled spikelet E lower glumes F upper glumes G lower lemmas H lower paleas I upper lemmas J upper paleas K stamens L pistil M caryopsis. (Drawn by Paweena Wessapak).

Figure 9. Cenchrus pedicellatus (Trin.) Morrone A habitat B inflorescence C spikelets with involucre D spikelets. (Photographs: Paweena Wessapak).