Panicum maximum

Panicum maximum Jacq.

Common name
Guinea Grass
Green Panic

Derivation
Panicum L., Sp. Pl. 55 (1753) & Gen. Pl. 5th edn, 29 (1754); Panicum: old Latin name for common millet (Setaria italica), from Latin panis (bread).

maximum- Latin for greatest. Culms very tall.

Published in
Icon. Plant. Rar. 1: 2, t. 13 (1781).

Common synonyms
Urochloa maxima (Jacq.) R.D.Webster
Urochloa maxima (Jacq.) R.D.Webster var. maxima
Urochloa maxima var. coloratum (C.White) R.D.Webster
Urochloa maxima var. trichoglume (Robyns) R.D.Webster

Habit
Perennial or annual (rarely), tufted. Rhizomes short. Stolons absent or present. Basal leaf sheaths pubescent. Culms erect or geniculately ascending, robust or of moderate stature or slender, (25–)75–200(–450) cm tall, without nodal roots or rooting from lower nodes. Mid-culm internodes glabrous or hispid or pilose. Mid-culm nodes glabrous or pubescent or bearded. Leaf-sheaths wider than blade at the collar or as wide as blade at the collar. Ligule a fringed membrane. Leaf-blade base truncate. Leaf-blades linear or lanceolate, (6–)12–40(–100) cm long, (4–)10–35 mm wide. Leaf-blade surface glabrous or pubescent or pilose. Leaf-blade margins scabrous. Leaf-blade apex acuminate.

Inflorescence
Inflorescence compound, a panicle. Panicle open, oblong or pyramidal, 12–60 cm long. Primary panicle branches 6–8 in number, ascending or spreading, whorled at lower nodes.

Spikelets
Spikelets solitary or in pairs. Pedicels straight or flexuous, glabrous or bearing a few hairs, hairy at tip, tip discoid. Fertile spikelets 2-flowered, comprising 1 fertile floret, without rhachilla extension, oblong, dorsally compressed, obtuse or acute, (2.5–)3–4.5(–5) mm long, falling entire. Rhachilla internodes brief up to lowest fertile floret.

Glumes
Glumes dissimilar, thinner than fertile lemma. Lower glume ovate, 0.8–1.1 mm long, 33–50% of length of spikelet, membranous, 1–3-nerved. Lower glume lateral nerves obscure. Lower glume surface glabrous or pubescent. Lower glume apex obtuse or acute. Upper glume ovate, 2.1–3.5 mm long, 100% of length of spikelet, membranous, 5-nerved. Upper glume surface glabrous or pubescent. Upper glume apex acute, muticous or mucronate.

Florets
Basal sterile floret 1, with palea. Lemma of lower sterile floret similar to upper glume, ovate, 2.7–3.5 mm long, 100% of length of spikelet, membranous, 5-nerved, without grooves, glabrous or pubescent, acute. Fertile lemma oblong, dorsally compressed, 1.9–5 mm long, indurate, pallid. Lemma surface rugose. Lemma margins involute. Lemma apex obtuse, mucronate. Palea involute, indurate. Palea surface rugose.

Continental Distribution:
Europe, Africa, Temperate Asia, Tropical Asia, Australasia, Pacific, North America, South America.

Australian Distribution:
Western Australia, Northern Territory, South Australia, Queensland, New South Wales.

Western Australia: Drummond, Warren. Northern Territory: Darwin & Gulf. South Australia: Murray. Queensland: Cook, Burke, North Kennedy, South Kennedy, Port Curtis, Leichhardt, Wide Bay, Darling Downs, Moreton, Warrego, Maranoa. New South Wales: North Coast, Central Coast, Northern Tablelands, North-Western Slopes, Central-Western Slopes, North-Western Plains.

Classification. (GPWG 2001):
Panicoideae: Paniceae

Notes
Introduced. Native to tropical Africa but now widely introduced in the tropics and subtropics of the world. Flowers essentially throughout the year. There are three varieties and two known naturalised cultivars.

1.	Culms decumbent, rooting at nodes	*P. maximum var. maximum cv. Embu (QLD)
	Culms tufted and erect, not rooting at nodes	2

2.	Spikelets indistinctly hairy	*P. maximum var. trichoglume (NSW QLD) Urochloa maxima var. trichoglume
	Spikelets glabrous	3

3.	Leaf hairy at junction of sheath and blade	*P. maximum var. coloratum (QLD) Urochloa maxima var. coloratum
	Leaf glabrous at junction of sheath and blade	4

4.	Plant 1.8–2 m tall; leaf-blades 15–18 mm wide	*P. maximum var. maximum (NSW NT SA WA QLD) Urochloa maxima var. maxima
	Plant 3–3.5 m tall; leaf-blades 24–26 mm wide	*P. maximum var. maximum cv. Hamil (QLD)

Panicum maximum Jacq. var. maximum
W.A., N.T., Qld, and N.S.W. In tropical heaths, tropical and subtropical rain forests, tropical and subtropical wet sclerophyll forests, dry sclerophyll forests, tropical and subtropical sub-humid woodlands, and coastal grasslands. An important forage grass.

Panicum maximum var. trichoglume Eyles ex Robyns
Qld, N.S.W. and SA. In tropical and subtropical rain forests, tropical and subtropical wet sclerophyll forests, dry sclerophyll forests, tropical and subtropical sub-humid woodlands, semi-arid shrub woodlands, and acacia shrublands. A selected form of the typical variety frequently introduced for pasture improvement.

Panicum maximum var. coloratum C.T.White
Qld.