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Graminae
Common names
Pit-pit (New Guinea), tropical reed (Australia).
Description
A perennial reed with long rhizomes and robust, erect culms
to 3 m. The leaves are 15-30 cm long and nearly 2.5 cm broad; inflorescence
is a large plumelike panicle with capillary branches and small, slender
spikelets. It is leafy up the panicle. Phragmites can be easily distinguished
from Arundo and Neyraudia by the silky beards at the bases of the lowest
panicle branches, which are absent in the other two (Dabadghao & Shankarnarayan,
1973).
In New Guinea the reed occurs from near sea-level to at least 2 000
m. It thrives in a rainfall regime from 200 to 5 000 mm in swamps (India).
It grows in standing water and is therefore tolerant of flooding. It usually
grows in clay soils ranging from strongly acid (pH 4.5) to slightly alkaline
(pH 7.5).
Natural habitat
Along streams, in wet grassland and in swamps in Africa, India,
New Guinea and northern Australia.
Genetics and reproduction
The chromosome number is 2n=36, 38, 48 (Fedorov, 1974).
Economics
It disappears quickly under the impact of cutting and burning.
In New Guinea, P. karka swamps at 1 500 m elevation can be used for grazing,
if drainage can be provided. The pit-pit is burnt in the dry season and
the regrowth grazed at a high stocking rate (25-40 beasts/ha). The cattle
graze shoulder to shoulder. A live- weight gain of almost 1 kg/head per
day is possible. The regrowth can be grazed three to four times before
the pit-pit is exhausted (Graham, personal communication).
It withstands heavy floods and is an excellent stabilizer of eroding
river banks (Rose-Innes, 1977). Saccharum robustum Brandes and Jesueit
ex Grassl. is also known as pit-pit in New Guinea.
Further reading
Rose-Innes, 1977.
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