Pennisetum is from the Latin pena meaning feather and seta meaning bristle and refers to the feather like bristles on the flowers, of some species in this genus.
Setaceum
Fountain grass.
Summary:
A stiff, narrow, rough leaved, dense, perennial tussock with long, upright or often drooping,cylindrical, feathery, purple seed heads.
Description:
Cotyledons:
One.
Leaves:
Blade - Long and slender, parallel sided, erect, rigid, tough, flat, folded or rolled, 100-450 mm long by 2-3.5 mm wide, obvious ribs, rough on the upper surface and edges, smooth on the underside. Mainly hairless with a few hairs near the base. Fine pointed soft almost bristle like tip. The side of one leaf overlaps the next leaf. Parallel veins.
Ligule - Short fringe of hairs, 0.5 mm long.
Auricles - None.
Sheath - Striped, keeled towards the top. Hairy especially on the edges.
Stems:
Erect, or ascending from a knee at the lower nodes, many, stiff, densely to loosely tufted, 500-1000 mm tall, cylindrical or flattened near the top. Unbranched or branching near the base. 3-5 nodes. Hairless or slightly hairy or rough below the flower head.
Flower head:
Erect or drooping, cylindrical, moderately dense spike like panicle, 100-350 mm long by 12-20 mm wide(excluding the bristles), feathery, straw yellow to red or purplish. Main axis(rachis) striped, hairy and roughened.
A structure(involucre) below the spikelets consists of a hairy stalk to 3 mm long with up to 25 bristles. The bristles are straight, slender, free to the base, become purple with age, of differing lengths, 16-40 mm long with most of them 16-26 mm long, roughened and loosely feathery with wart based hairs. One bristle is much stouter and longer than the others.
The seed head is composed of many of these involucres.
Flowers:
Spikelets - Narrowly egg shaped, 4.5-7 mm long, 2 flowered, finely pointed, single and stalkless or in groups of 2-3 with the side ones on hairy stalks(pedicels) to 1.5 mm long. Hairless or with a tiny beard at the base. Hairless.
Florets - Lower one empty or rarely male. Upper one bisexual or male in the side spikelets of the group
Glumes - Lower one, absent or a rounded, translucent scale to 1 mm long. Upper one narrowly egg shaped, membranous, 1 nerved, up to 5 mm long with an acute tip that usually has a short sharp flexible point.
Palea - Lower one absent or egg shaped. Upper one slightly shorter than the lemma.
Lemma - Lower one egg shaped, 4-7 mm long, 1-5 nerved, roughened on the nerves with an acute tip that usually has a short sharp flexible point. Upper one egg shaped to oblong, 4.5-7 mm long, as long as the spikelet, membranous, usually 5 nerved, roughened near the tip, with an acute tip or a sharp flexible spine to 1 mm long. The upper edges occasionally have tiny hairs.
Stamens -
Anthers -
The bristles(involucre) and spikelets fall together when mature.
Fruit:
Bristly spikelets.
Seeds:
Enclosed in fruit.
Roots:
Large fibrous root system.
Key Characters:
Inflorescence well developed, narrowly cylindrical, terminal, pedunculate spike-like panicle, 100-350 mm long, straw coloured but usually conspicuously purple.
Spikelets not gaping and exposing the caryopsis. Bristles of involucre the same length or exceeding the spikelets, 16-40 mm long with most 16-26 mm long. Inner bristles conspicuously plumose giving the panicle a feathery appearance. Perennial.
Biology:
Life cycle:
Perennial grass up to 1000 mm tall. Seeds germinates autumn to winter and grow slowly until spring. The main growth occurs over summer and it is semi dormant in winter. Flowers mainly in spring and recorded from July-November and occasionally in March.
Physiology:
Reproduction:
By seed.
Flowering times:
Spring in western NSW.
July to November with occasional flowers in March in Perth.
Winter and Spring mainly with some in autumn in WA.
Seed Biology and Germination:
Vegetative Propagules:
None.
Hybrids:
Allelopathy:
Population Dynamics and Dispersal:
Produces large amounts of seed.
Origin and History:
North east Africa. Middle East.
Distribution:
NSW, QLD, SA, WA.
Habitats:
Wet areas.
Climate:
Temperate. Mediterranean.
Soil:
Plant Associations:
Significance:
Beneficial:
Ornamental.
Used for binding sand to prevent erosion.
Detrimental:
A weed of wet areas, table drains, roadsides, railways, grass lands, bush land and disturbed areas.
Toxicity:
Not recorded as toxic.
Legislation:
None.
Management and Control:
Drain wet areas.
Grazing and cropping usually provide adequate control.
Regular mowing usually provides control.
Thresholds:
Eradication strategies:
Spray plants until just wet with a mixture of 10 mL of glyphosate 450g/L plus 2.5 mL of Pulse Penetrant per litre of water in late spring and autumn each year. Burn or slash tops 8 weeks before or after spraying.
Isolated plants amongst other vegetation can be treated by selectively wiping leaves and stems with a mixture of 1 part glyphosate in 2 parts water.
Fluazifop can be used in sensitive situations where a high degree of selectivity is required. Use 5 mL Fusialde212® plus 10 mL spray oil per litre of water and spray plants until just wet any time they are actively growing. Repeat every 3 months if necessary.
It is very difficult to hand weed because of the large fibrous root system. Backhoes can be used to remove large plants. Dispose of plants on dry sites or bury more than a metre deep.
Herbicide resistance:
Biological Control:
Related plants:
African Feather grass (Pennisetum macrourum)
Elephant grass (Pennisetum purpureum)
Feathertop. (Pennisetum villosum)
Kikuyu (Pennisetum clandestinum)
Mission grass (Pennisetum polystachion)
Pearl Millet (Pennisetum glaucum)
Swamp Foxtail (Pennisetum alopecuroides)
Pennisetum pedicellatum
Plants of similar appearance:
Grasses.
References:
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P52.
Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P128. Photo.
Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P64-65. Photo.
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).
Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #945.9.
Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P976.
Paterson, J.G. (1977). Grasses in South Western Australia. (Western Australian Department of Agriculture Bulletin 4007). P70.
Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.