Amphibromus fluitans Kirk, Trans. & Proc. New Zealand Inst. 16: 374 (1884).

T: Hab. North Island: in shallow waters, margins of Waihi Lake and Creek, [New Zealand]; holo: CHR?, dupl. K, US.
A. gracilis P.Morris, Victorian Naturalist 51: 145 (1934). T: near Melbourne (towards Yarra at Kew), 6 Feb. 1934, Dakin s.n.; lecto: MEL 100528, dupl: BRI

Illustrated in: Fl. N.S.W. 4: 596 (1993).

Vegetative form. Perennial, decumbent, rhizomatous or stoloniferous. Culms to 75 cm high, 3-5 noded. Mid-culm nodes glabrous, exposed, constricted. Mid-culm internodes hollow, glabrous or scabrous, terete. Leaves non-auriculate. Basal leaf sheaths not keeled, terete, slightly scabrous, with the veins equally striate. Ligule 6.5-12 mm long, membranous, acute, entire (becoming lacerated with age). Leaf blades flat or involute, linear, to 250 mm long, 2-4.5 mm wide; adaxially scabrous, channelled; abaxially scabrous, with the veins equally striate.

Reproductive organization. Plants bisexual. Incomplete spikelets absent. Inflorescence of cleistogamous spikelets, or chasmogamous spikelets (with cleistogamous or chasmogamous florets).

Inflorescence. Inflorescence a panicle, erect, contracted, symmetrical, partially exserted. Rachides to 350 mm long, terete (becoming angled towards apex), glabrous (becoming scabrous toward apex). Primary inflorescence branches paired or clustered (to 8.5 cm long). Spikelets erect, spreading.

Hermaphrodite (`perfect') spikelets. Hermaphrodite spikelets pedicellate, 9-15 mm long, laterally compressed, not disarticulating as a separate unit, disarticulating above the glumes. Pedicels to 20 mm long, scabrous to hispid. Glumes two per spikelet, dissimilar, unequal in length, shorter than the florets (?), slightly shorter than the proximal lemma (?). Lower glume c. 2/3s the length of the upper glume (?), narrowly ovate, 2.7-3.7 mm long, 0.7-1.4 mm wide, weakly keeled, muticous, margin membranous (broadly); 1-3 veined, midvein glabrous; intercostal regions glabrous. Upper glume ovate, 3.4-4.5 mm long, 1.1-1.7 mm wide, weakly keeled, muticous, margin membranous (broadly); 3-5 veined, midvein glabrous; intercostal regions glabrous. Rudimentary florets distal to the hermaphrodite florets. Incomplete florets absent. Hermaphrodite florets (5-)6-10(-12) per spikelet (cleistogamous or chasmogamous). Rachilla disarticulating between the florets, disarticulating directly below the florets, segments bearded at the apex, apically prolonged; terminated by a rudimentary floret. Callus present, blunt, hirsute (?). Lemma laterally compressed, 3.7-5 mm long, not keeled, bidentate (teeth 0.3-0.6 mm long), 2 -lobed, awned. Lemma (5-)7 veined. Lemma veins not confluent apically; intercostal regions scabrous (to hispid). Awns 1, median. Median awn much longer than the body of the lemmas, 11-17 mm long, 1 veined, dorsal, arising from the upper half of the lemma or from the mid-point of the lemma or from the lower half of the lemma (from above the midpoint to 2/3s of the lemma length from the tip), straight, column twisted (slightly) or column not twisted, scabrous. Palea fully developed, minute to slightly shorter than the lemmas, 2-keeled, keels wingless, acute, margin smooth; 2 veined, veins ciliate; intercostal regions glabrous. Lodicules 2, free, hyaline, acute, glabrous. Stamens 3. Anthers 1.48-1.7 mm long. Cleistogamous anthers 0.5 mm long. Ovary glabrous.

Fruit. Fruit free from both lemma and palea, oblong, dorsiventrally compressed (dorsally), 1.3-1.7 mm long, glabrous (yellow-brown). Hilum 25-30% the length of the fruit, linear (red-brown). Embryo 10-20% the length of the fruit.

Distribution. Endemic. New South Wales and Victoria.

Ecology. Helophytic; in open habitats. Usually in permanent swamps.

Classification. Pooideae; Poodae; Aveneae.

References. Morphology: Jacobs & Lapinpuro 2: 728-9 (1986). Taxonomy: Jacobs & Lapinpuro 2: 728 (1986).

Cite this publication as:
C.M. Weiller, M.J. Henwood, J. Lenz and L. Watson (1995 onwards). `Pooideae (Poaceae) in Australia - Descriptions and Illustrations'. URL http://muse.bio.cornell.edu/delta/
Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993) should also be cited.

References and Acknowledgements