Amphibromus pithogastrus S.W.L.Jacobs & Lapinpuro, Telopea 2: 724 (1986).

T: Norway, via Oberon, N.S.W., 26 Jan. 1953, J.Vickery; holo: NSW

Illustrated in: Fl. N.S.W. 4: 597 (1993) (spikelet and floret).

Vegetative form. Perennial, caespitose. Culms to 100 cm high, 2-3 noded. Mid-culm nodes glabrous, exposed, constricted (occasionally with corm-like swellings on the lower nodes). Mid-culm internodes hollow, glabrous, terete to compressed. Leaves non-auriculate. Basal leaf sheaths not keeled, terete, glabrous, with the veins equally striate. Ligule 2-5 mm long, membranous, acute, entire (becoming lacerated with age). Leaf blades flat or involute, linear, to 200 mm long, 1.5-5 mm wide; adaxially glabrous or adaxially scabrous, channelled; abaxially glabrous, with the veins equally striate.

Reproductive organization. Plants bisexual. Incomplete spikelets absent (?). Inflorescence of cleistogamous spikelets.

Inflorescence. Inflorescence a panicle, erect, contracted, symmetrical. Rachides to 250 mm long, terete (becoming angled toward apex), glabrous (becoming scabrous toward apex). Primary inflorescence branches paired (to 8 cm long), appressed. Spikelets erect, spreading.

Hermaphrodite (`perfect') spikelets. Hermaphrodite spikelets pedicellate, 8-15 mm long, laterally compressed, not disarticulating as a separate unit, disarticulating above the glumes. Pedicels to 30 mm long, erect, hispid. Glumes two per spikelet, dissimilar (the upper longer and broader), unequal in length (green with broad straw-coloured margins), shorter than the florets, approximately half the proximal lemma in length (?). Lower glume c. 2/3s the length of the upper glume (?), 3.6-5.3 mm long, 1.4-2.3 mm wide, weakly keeled, acute, muticous; 3-5 veined, midvein glabrous; intercostal regions glabrous. Upper glume elliptic, 4.7-7.3 mm long, 2.2-3.6 mm wide, weakly keeled, acute, muticous; 5-7 veined, midvein glabrous; intercostal regions glabrous. Rudimentary florets distal to the hermaphrodite florets (?). Incomplete florets absent (?). Hermaphrodite florets 2-6 per spikelet (all cleistogamous). 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 (? swollen), 5.6-7.5 mm long, not keeled, dentate (the 2 central teeth 0.3-0.65 mm long, the lateral teeth shorter), 4 -lobed; apex membranous; awned. Lemma 7 veined (the veins dark-coloured near the apex). Lemma veins not confluent apically (but extending to the margins), papillose, with the hairs on all the veins; intercostal regions papillose. Awns 1, median. Median awn about as long as the body of the lemmas or much longer than the body of the lemmas, 9-16 mm long, 1 veined, dorsal, arising from the upper half of the lemma (1/4-2/3s of the lemma length from the tip), geniculate, column twisted. Palea fully developed, 1/2 the length of the lemmas to slightly shorter than the lemmas, 2-keeled, acute; 2 veined, veins ciliate; intercostal regions glabrous. Lodicules 2, free, hyaline, lobed, with margin divisions lateral, glabrous. Stamens 3. Cleistogamous anthers 0.6-1.5 mm long.

Fruit. Fruit free from both lemma and palea, oblong, dorsiventrally compressed (dorsally), 1.6-2.1 mm long, glabrous (yellow-brown). Hilum 40-50% the fruit length, linear (dark red-brown). Embryo 25-30% the fruit length.

Distribution. Endemic. New South Wales and Victoria.

Ecology. Helophytic. Grows in seasonally swampy areas. Flowers in response to rain or flooding.

Classification. Pooideae; Poodae; Aveneae.

Similar to A. neesii but differing in the dark-colourd veins, the longer lemma lobes and the more swollen lemma.

References. Morphology: Jacobs & Lapinpuro 725 (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