Scientific Name
Paspalum dilatatum
Common Names
paspalum, dallis grass
Origin
South America
Family
Poaceae
Distinguishing Characteristics
This is a tufted perennial (living for longer than 1 growing season) growing from a solid, hairy base or 'crown'. This is a tall, erect grass to about 2m high.
Lower sheaths of leaves are hairy. The leaf blades are hairless with an asymmetric ligule (appendage at base of leaf with unequal sides). The leaf blade is angled along the midrib, and is long and narrow, bright green, sparsely long-hairy around where it meets the stem.
Inflorescence (a group of flowers) usually has 3 to 7 spike-like racemes (groups of flowers on a stem) but could be up to 11. Each raceme is usually less than 5 cm long (but can be up to 12cm long) and usually at almost right-angles from the stem. Flowers in summer to autumn.
The seed heads have paired seeds lined up in 4 rows. Seeds are brown when mature and fringed with fine hairs and may feel sticky.
This is a major weed of the world. It has some value as a pasture grass.
This plant holds to the ground very firmly. To remove it requires a sharp knife and some muscle to cut around the base and lift the plant from the ground. It can alternatively be sprayed successfully with a 1:100 glyphosate:water mix.
Other plants easily confused with this plant
Paspalum dilatatum may be confused with other Paspalum species of which there are around 330 species all mostly from Central and South America. There are 5 species native to Australia. Some of the other species do not have a tufted base, some are not hairy and others with a tufted base generally have more racemes.
Paspalum quadrifarium (tussock paspalum) grows to 2m high with 15-40 rust coloured racemes.
Paspalum urvillei (vasey grass) grows to about 2.5m tall with 6-30 racemes usually held erect.
Paspalum paniculatum (Russel River grass) grows to 2m with 10-30 scattered erect then spreading racemes.
Sources & References
"Weeds - an illustrated botanical guide to weeds of Australia" by B. A. Auld and R. W. Medd
"Plantnet FloraOnline" (2005) http://plantnet.rbgsyd.nsw.gov.au/
Prepared by Justin KY Chu, July 2005
Checked and updated IEWF, January 2007