MONOCOTYLEDONS

POACEAE - Grass Family  

Avenaspecies(oats) are tufted annual herbs to 1.5m tall. The inflorescence is a drooping, usually one-sided panicle. A. barbata(bearded oat) is the most common species in uncropped situations, including roadsides, wasteland and disturbed bushland, occasionally extending into crop margins. It is a native of the Mediterranean. The mature seeds are slender in comparison with A. fatua, and the hairs on the lemma often stick out at right angles. The 'seeds' (in fact seeds tightly enclosed in the palea and lemma) are usually straw-coloured. The tips of the palea and lemma extend at least as far as the bend in the awn.


Avena barbata, RR

A.fatua(wild oat) is the main oat species found as a weed of cropping. The seeds are fatter than in A. barbata, the hairs on the lemma do not stick out as much and are commonly dark brown (though they can be straw-coloured, grey or brown). The tips of the lemma and palea are shorter than the distance to the elbow of the awn. Native to southern Europe. Both of these are abundant and widespread weeds throughout southern Western Australia. A. sterilis subsp. ludoviciana (sterile oat) is restricted to cropping areas and appears to be increasing. It is differentiated from A. fatua by the fact that the seeds in the spikelets do not easily come apart at maturity. Also occasionally found is A. strigosa (bristle oat) and A. sativa (oat). The latter is commonly encountered along country road and rail verges where grain has fallen during shipment. All are native to the Mediterranean and Asia.


Avena spikelets, LB

Axonopus compressus (broad-leaved carpet grass) is a rhizomatous or stoloniferous perennial to 30cm tall. The leaves are glabrous, flat, 4-10mm wide and often folded along the midrib. The inflorescence is erect and slender, composed of two to three spreading spikes on a short axis (like that of a paspalum). It is used as a lawn grass and has escaped into creeks from Perth to Margaret River. A. affinis (narrow-leaved carpet grass), also a perennial, is an occasional weed in lawns and gardens in
the Perth area. It is distinguished from
A. compressus by its narrow, hairless leaves, 2-4mm wide. Both are native to America.


Axonopus compressus , PH

Bothriochloa pertusa (Indian bluegrass) is an aromatic, prostrate or decumbent perennial to 70cm. The inflorescence is erect and the spikelets digitate. Flowers from March to May. A native of tropical Asia, introduced as a pasture grass and spreading in the Kimberley and at Three Springs. There are also two native species; consult a specialist text to separate them.
Brachypodium distachyon (was Trachynia distachyon) (false brome) is an erect annual to 50cm tall with flat, scabrous leaves to 8cm long. The inflorescence is erect above the leaves and is a many-flowered, spike-like raceme, with long, prominent awns, produced in spring. A weed of urban bushland and of the western edge of the wheatbelt, but under-reported, probably because of superficial similarity to Bromus species. A native of the Mediterranean and western Asia.


Brachypodium distachyon , PH

Briza maxima (blowfly grass, quaking grass) is a slender, tufted annual to 60cm tall with flat, linear leaves tapering to an acute apex. The inflorescence is a loose panicle of nodding spikelets, usually three to five up to 15 per inflorescence, that are produced in spring. It is a widespread weed of wasteland, granite rocks, wetlands and woodlands from Geraldton to Esperance.


Briza maxima , PH

B. minor (shivery grass, lesser quaking grass) is a slender, tufted annual to 30cm tall with flat leaves. The inflorescence is a loose panicle of nodding green spikelets that are smaller and more numerous than in B. maxima, produced in spring. A widespread weed of gardens, wasteland, granite rocks and wetlands from Shark Bay to Esperance. Both are native to the Mediterranean.


B. minor , RR

Bromus (brome grasses) is a genus of over 100 species. There are 24 introduced and one native species in Australia, 11 species have been recorded in Western Australia. B. alopecuros is a slender annual to 60cm tall, with hairy leaves. It differs from other Bromus species in having awns that are twisted and bent away from the erect spikelet. A native of the Mediterranean, and a weed of cereal crops in southern Western Australia. B. catharticus (prairie grass) is a tufted annual or perennial to 1m tall with glabrous, loosely folded leaves. The inflorescence is a large, open, drooping panicle to 40cm long comprising compact, glabrous, awnless spikelets. A native of South America, it was imported as a pasture grass and is now found on moist wasteland from Perth to Albany.


Bromus catharticus , RC

B. diandrus (great brome) is a tufted annual to 80cm tall with softly-hairy, flat or loosely folded leaves. The inflorescence is a loose, usually drooping, panicle to 15cm long, of 4 to 10 flowered oblong spikelets with a very prominent, rough awn to 60mm long. Flowers in spring. Native to the Mediterranean, it is a widespread and serious weed of offshore islands, wetlands, road verges, granite rocks, pastures and crops in southern Western Australia.


B. diandrus , GK

It is possible that some of the material currently identified as B. diandrus is the similar B. rigidus (that has shorter, erect, panicle branches). B. hordeaceus (soft brome) is an erect annual to 80cm tall with flat, hairy leaves. The inflorescence is an erect, dense, ovate to oblong panicle to 10cm long, flowering in spring. The hairy spikelets are plump with a short, straight awn. A widespread weed of damp pastures (where it may be useful forage), wetlands and creeks in southern Western Australia. Native to Europe. B. japonicus (Japanese brome) is very similar to the native B. arenarius. It flowers in spring and is a widespread weed of offshore islands, sandy soils and saline lakes from Shark Bay to Kalgoorlie. Native to Asia.


B. hordeaceus , RR

B. madritensis (Madrid brome) is an erect annual to 60cm tall with flat, hairy or glabrous leaves. The inflorescence is an erect, dense, ovate panicle to 10cm long and the usually purplish spikelets are plump, with an awn to 20mm long. Native to Europe, flowering in spring. A widespread weed of very disturbed sites and crops in southern Western Australia. B. rubens (red brome) is similar to the preceding species, but is usually smaller (to 40cm tall) and more compact, andm B. madritensis has a glabrous peduncle and more open inflorescence. A widespread weed of very disturbed areas such as firebreaks throughout the south-west. A native of the Mediterranean. B. sterilis, B. tectorumand B. molliformisare also recorded as occurring here in some books published in other states. B. coloratus (very similar to B. hordeaceus, but has compressed spikelets) and B. lanceolatus (very similar to B. hordeaceus, but has a longer, compressed spikelet with spreading awns) have been recorded but do not seem to have become naturalised.


B. rubens , RR

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