Anthoxanthum aristatum Boiss., Voy. Bot. Espagne 2: 638 (1842).

T: In Sardinia (Thomas), Hispania interiori propé Matritum (Carreno)

Vegetative form. Annual, caespitose. Leaves scattered along the culms. Culms slender, 55-65 cm high, branched above (rooting at the lower nodes), 4-7 noded. Mid-culm nodes glabrous, exposed, slightly constricted. Mid-culm internodes glabrous, terete. Young shoots intravaginal. Shoots aromatic (coumarin scented). Leaves non-auriculate (but with setae at the sheath-blade junction). Basal leaf sheaths not keeled, terete, glabrous, with the veins equally striate, with margins free, membranous, smooth. Ligule 1.7-2.1 mm long, membranous, smooth, obtuse, entire. Collar glabrous. Leaf blades becoming dry and disintegrating flat, linear, to 55 mm long, to 2.3 mm wide; adaxially glabrous or adaxially pilose (sparsely), not grooved; abaxially glabrous, with the veins equally striate; with margins smooth or with margins scabrous, apices acute. Prophyll 15-32 mm long, keels retrorsely scabrous.

Reproductive organization. Plants bisexual. Rudimentary spikelets at the base of the inflorescence, or absent. Incomplete spikelets absent. Hermaphrodite florets protogynous. Inflorescence of chasmogamous spikelets (?).

Inflorescence. Inflorescence a panicle, erect, contracted, 5-8 mm wide, narrow and spike-like, oblong, symmetrical, fully exserted. Main inflorescence axis 75-170 mm long. Peduncles 57-140 mm long, glabrous. Rachides 15-35 mm long, terete, usually glabrous. Primary inflorescence branches glabrous; solitary or paired, usually branching at the base, spreading, spiral, without spikelets inserted at the base (?). Spikelets 2-3 on a typical ultimate inflorescence branch, spiral, on second order branches, erect, spreading.

Hermaphrodite (`perfect') spikelets. Hermaphrodite spikelets pedicellate, 5.1-6.8 mm long, laterally compressed, narrowly ovate, not disarticulating as a separate unit, disarticulating above the glumes. Pedicels 0.4-2.1 mm long, erect, slender, sparsely scabrous to pubescent, straight. Glumes two per spikelet, similar, unequal in length, equalling the proximal lemma and longer than the proximal lemma (G1 equal and G2 longer). Lower glume c. 1/2 the length of the upper glume, ovate, 3.4-3.8 mm long, 0.85 mm wide, membranous, keeled, acute, entire, apiculate, margin margin smooth; 1 veined, veins prominent, midvein scabrous; intercostal regions glabrous, or intercostal regions scabrous (the hairs sparse and antrorse). Upper glume large, enclosing the florets, narrowly ovate, 5.9-6.3 mm long, 0.85 mm wide, membranous, keeled, acute, entire, apiculate, margin margin smooth; 3 veined, veins prominent, midvein papillose; intercostal regions papillose to intercostal regions scabrous (minutely). Rudimentary florets absent. Incomplete florets present, proximal to the hermaphrodite florets. Proximal incomplete florets 2 per spikelet, neuter (reduced to well developed lemmas), clearly specialised and modified in form, awned, epaleate. Incomplete lemmas becoming decidedly firmer than the glumes, clearly longer than the hermaphrodite lemma (the fertile floret 3/4s the length), equal in length, (dorsally) narrowly elliptic, 2.8-3 mm long, 0.4-0.6 mm wide, chartaceous, not keeled, apices the hairs long, straight, golden, acute (dorsally in situ), emarginate or bifid (appears irregular laterally), awned, with margins ciliate; 5 veined. Incomplete lemma veins not confluent apically, obscure; pilose, with hairs on all veins, extending the length of the veins; intercostal regions pilose, the hairs only at the base (i.e. the hairs on the lower 2/3s only, not on the colourless lobes). Incomplete lemma awns 1, median. Incomplete lemma median awn dorsal (arising from above the midpoint c.1/3 from the apex of the first lemma, and from near the base of the second lemma), much longer than the body of the lemmas, markedly unequal in length (the awn of the first lemma 3.6-3.8 mm long, straight, scabrid; the awn of L2 7.4-7.6 mm long, geniculate, with a pigmented, twisted column, scabrid), 3.6-7.6 mm long. Hermaphrodite florets 1 per spikelet, asymmetrical, glossy and golden-brown at maturity to bronze at maturity. Rachilla not disarticulating between the florets, glabrous, not obviously elongated between glumes or florets, not apically prolonged. Callus absent. Lemma becoming decidedly firmer than the glumes, broad, completely enclosing the palea, (dorsally) elliptic (rotund when open), 1.6-1.8 mm long, (dorsally) 0.7 mm wide, becoming indurate, not keeled, in situ acute (but truncate when open), in situ entire (but emarginate when open), muticous. Lemma margins smooth. Lemma veins obscure, glabrous; intercostal regions glabrous. Palea fully developed, slightly shorter than the lemmas, thinner than the lemmas, tightly clasped by the lemmas, elliptic, 1.2-1.4 mm long, 0.6 mm wide, chartaceous, keel-less, obtuse, apically notched, margin smooth; 1 veined, veins glabrous; intercostal regions glabrous. Lodicules absent. Stamens 2 (in overseas material). Anthers 4 mm long (in overseas material), basally 2-lobed. Ovary glabrous. Styles 2, apical, free to their bases.

Fruit. Fruit free from both lemma and palea, elliptical, slightly laterally compressed, 1.2-1.4 mm long, 0.7 mm wide, glabrous. Hilum 0.2 mm long, punctiform (?). Embryo 0.5-0.6 mm long, not waisted.

Distribution. Introduced. Victoria. World distribution: Western Eurasia, USSR and Mediterranean.

Ecology. Mesophytic; in open habitats. Flowers Jan.

Vouchers. Specimens examined morphologically: Vic.: between Burrowye & Thologolong, 7.2 km E of the Flaggy Creek crossing of the Murray Valley Hwy, 22 Jan. 1981, fringes of billabong on hard set, silty soils, N.H.Scarlett (MEL BRI).

Classification. Pooideae; Poodae; Aveneae.

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