Australopyrum retrofractum (Vickery) Á.Löve, Feddes Repert. 95: 442 (1984).

Agropyron retrofractum Vickery, Contr. New South Wales Natl Herb. 1: 340 (1951). T: Rock Flat near Cooma, N.S.W., Feb. 1893, E.Betche s.n.; holo: NSW, K.

Vegetative form. Perennial, erect, caespitose. Leaves scattered along the culms. Culms (27-)49.5-58(-95) cm high, unbranched above, 2-3 noded. Mid-culm nodes glabrous (slightly sunken, lightly pigmented). Mid-culm internodes hollow, glabrous (although acropetally puberulous for c. 5 mm), terete. Young shoots intravaginal. Leaves auriculate. Auricles 1.5-2 mm long, glabrous. Basal leaf sheaths not keeled, terete, glabrous or scabrous to puberulous (sparsely), with margins free, hyaline to membranous, smooth or ciliate (sparsely). Ligule 0.2-1 mm long, hyaline, smooth, truncate, entire. Collar glabrous. Leaf blades almost flat to involute (but not strongly so), linear, 70-128(-260) mm long, 3.5-5 mm wide; sparsely to densely adaxially scabrous to adaxially pilose (indumentum confined to veins); abaxially glabrous or abaxially puberulous to abaxially pilose (isolated to sparse, confined to veins); with margins smooth to with margins ciliate, apices acuminose; convolute in bud.

Reproductive organization. Plants bisexual. Spikelets homomorphic. Incomplete spikelets absent. Inflorescence of cleistogamous spikelets (although anthers exserted from some florets).

Inflorescence. Inflorescence a single spike to a raceme, open (spikelets not imbricate), oblong. Main inflorescence axis 170-263(-570) mm long. Peduncles 88-220(-580) mm long, glabrous. Rachides 50-95 mm long, strap-like to subterete, densely puberulous to pilose (retrorse for the proximal 3 nodes). 11-19 spikelets on the rachis. Rachis angles densely puberulous to pilose (retrorse). Spikelets distichous, spreading to divaricate.

Hermaphrodite (`perfect') spikelets. Hermaphrodite spikelets sessile to pedicellate, 8-15 mm long, slightly laterally compressed or not noticeably compressed, ovate to obovate, disarticulating as a separate unit, disarticulating above the glumes. Pedicels 0-1.5 mm long. Glumes two per spikelet, diverging from the spikelets, free (divergent, not basiscopic), similar, equal in length, lateral to the rachis. Lower glume narrowly oblong to narrowly ovate, 4.75-7 mm long, 0.5-1 mm wide, carnose to cartilaginous, asymmetrically, slightly keeled, acuminate to acute, muticous or mucronate (shortly), margin hyaline to margin membranous (broadened proximally), margin smooth; 5 veined, veins obscure to veins prominent (slightly), midvein glabrous or midvein scabrous (isolated, acropetally); intercostal regions glabrous. Upper glume narrowly oblong to narrowly elliptic, 5.75-7 mm long, 0.5-2 mm wide, carnose to cartilaginous, asymmetrically, slightly keeled, acuminate to acute, muticous or mucronate (shortly), base broadly cuneate, margin hyaline to margin membranous, margin smooth; 7 veined, veins obscure to veins prominent (slightly), acropetally, isolated midvein glabrous; intercostal regions glabrous. Incomplete florets present, distal to the hermaphrodite florets. Hermaphrodite florets 4-9 per spikelet. Rachilla disarticulating between the florets, disarticulating directly below the florets, straight, scabrous to puberulous, elongated between all florets, apically prolonged. Callus present, blunt, 0.2-0.5 mm long, glabrous. Lemma similar in firmness to the glumes, narrowly ovate to narrowly elliptic, 8.5-10 mm long, 1-1.75 mm wide, chartaceous to cartilaginous, acropetally not keeled, long acuminate or acute, entire or emarginate (rarely), muticous. Lemma margins smooth to ciliolate (sparsely). Lemma 7-8 veined. Lemma veins confluent towards the apex, obscure, scabrous, with the hairs on the midvein (or sometimes on all veins), with the hairs extending the length of the veins or with the hairs only at the vein base; intercostal regions glabrous or scabrous (sparsely), the hairs over the entire dorsal surface or only at the base. Palea fully developed or vestigial (rarely), 1/2 the length of the lemmas, thinner than the lemmas, tightly clasped by the lemmas, narrowly ovate to narrowly elliptic, 5-7 mm long, 1-1.5 mm wide, membranous to chartaceous, 2-keeled, keels wingless, acute, entire or apically notched (shallowly); 2 veined, veins scabrous; intercostal regions glabrous, or intercostal regions scaberulous. Lodicules 2, free, hyaline, acute to obtuse, lobed or with entire margins, with margin divisions lateral, basally glabrous to pilose (apically), the hairs dense to the hairs sparse. Stamens 3. Anthers 3-4 mm long (lobes distally divergent). Ovary without a conspicuous apical appendage, basally glabrous and pilose (apically), with the hairs only at the apex. Styles 2, free to their bases. Distal incomplete florets 1-3 per spikelet, male or neuter, merely underdeveloped, awnless or awned (shortly), epaleate. Distal male florets with 3 stamens.

Fruit. Fruit free from both lemma and palea, elliptical or obovoid, ventrally compressed, 4-5 mm long, 1 mm wide, pilose, with dense hairs, the hairs confined to a terminal tuft. Hilum 3-4 mm long, linear.

Abaxial leaf blade epidermis. Leaf anatomical data recorded.

Costal/intercostal zonation conspicuous; the intercostal zones bordering the midrib 12-22 cells wide; epidermis differentiated into long- and short-cells; long-cells different in shape costally and intercostally (costals rectangular with undulate long-cell walls, intercostals tending fusiform with moderately undulating or straight long-cell walls); long-cells of similar wall thickness costally and intercostally (the costals slightly thicker).

Microhairs absent.

Crown cells absent. Prickles present (and abundant); intercostal, costal, and marginal; antrorse and retrorse; variable in size and form (the intercostal prickles being smaller); of more than two types. Prickle bases paired with a short-cell (costally), or not paired with a short-cell (intercostally). Costal prickles along all zones; frequent in their files. 0-10 prickles per field in the costal zones either side of the midrib. Bases of the costal prickles longer than the width of an intercostal long-cell; barbs of the costal prickles more than twice as long as the bases. Intercostal prickles adjacent to the costal zones and in the astomatal files; 16-70 prickles per field in the intercostal zones bordering the midrib. Bases of the intercostal prickles about as long as the width of an intercostal long-cell; shorter than the stomata; barbs of the intercostal prickles about as long as the bases to up to twice as long as the bases to more than twice as long as the bases. Macrohairs present; costal; intergraded with long prickles; unicellular; robust; with thickened walls; sparse but frequent; more than twice as long as an intercostal long-cell. Macrohair bases one-celled.

Intercostal long-cells fairly constant in shape, or variable in shape; varying in shape within a single intercostal zone (rectangular laterally, tending fusiform centrally). Mid-intercostal long-cells markedly elongated; tending fusiform; somewhat inflated; long-cell walls straight, or slightly undulating; the undulations irregular; end walls vertical, or angled; the intercostal long-cell walls not conspicuously pitted; outer surfaces of intercostal long-cells not pitted. Papillae absent.

The costal zones all histologically similar; costal short-cells conspicuously in long rows, or predominantly as cork/silica cell pairs, or solitary, or occurring sporadically in the files of long-cells as mixtures of solitaries, pairs or short rows. Costal silica bodies present and perfectly developed; throughout the costal zones; horizontal-crenate, horizontal-smooth, horizontal-nodular, and cuboid (and tall and narrow or irregular in White Sn.).

Intercostal short-cells absent, or infrequent (rare); when present, mid-intercostal only; solitary. Unsilicified intercostal short-cells square to round or elliptical; walls straight. Intercostal silica bodies absent, or imperfectly developed; ,when present, cuboid.

Stomata common; present in all the intercostal zones; restricted in distribution within intercostal zones; arranged in definite rows. Stomatal rows in the widest intercostal zones 2-4; bordering the costae, or in the mid-regions and bordering the costae. Stomata 33-36-45 m long; with guard-cells overlapped by the interstomatals to having guard-cells flush with the interstomatals. Subsidiaries dome-shaped to parallel-sided. The domes of medium height, or low.

Photosynthetic pathway and related features. C3. XyMS+. The PBS sheaths of the primary lateral vascular bundles interrupted. Mestome sheath complete.

Transverse section of the leaf blade. Lamina mid-zone in transverse section open; more or less flat; exhibiting adaxial ribs only, or with ribs both adaxially and abaxially (rarely, seen in Michael RSBS 1545 only); the adaxial and abaxial ribs when present, opposite one another. Adaxial furrows deep; wide. Wavelength 137-279 m. Amplitude 33-105 m; depth of adaxial furrow/width of lamina 0.24-0.45. Adaxial furrows between all the vascular bundles. Adaxial ribs usually more or less constant in size, or irregular in size (i.e. of two size orders); round topped; opposite all vascular bundles (excluding the minor bundles adjoining the midrib which do not always form ribs). Vascular bundles in the mid-lamina 17-25; 1 per rib. Abaxial furrows absent, or present between the vascular bundles (when present). Abaxial ribs when present, opposite all the vascular bundles (though slight); smaller than adaxial ribs.

Midrib pronounced in outline, or not pronounced in outline (rarely); adaxially raised and rounded; prominent abaxially; 1 keeled abaxially; tissue layout similar to that of other primary vascular bundles. Vascular bundles in the mid-lamina region of the midrib 1. The median vascular bundle with a protoxylem cavity; with an enlarged protoxylem vessel; without sclerosed phloem. Midrib without colourless tissue adaxially; without lacunae. The lamina symmetrical on either side of the midrib.

Mesophyll chlorenchyma non-radiate; loosely packed. Mesophyll without lacunae; without any obvious adaxial palisade; without `circular cells'; not traversed by columns of colourless cells; without arm cells; without fusoids. Bulliforms present in discrete groups. The bulliform groups situated between vascular bundles. The bulliform groups without contiguous colourless mesophyll cells; small; simple, irregular, and of small cells, or simple, fan-shaped (with contiguous irregular bulliform cells). Abaxial epidermis of bulliform-like epidermal cells.

The major and minor vascular bundles alternating; outlines of primary vascular bundles more or less circular; primary vascular bundles centrally situated. Primary lateral vascular bundles with adaxial sclerenchyma; with abaxial sclerenchyma; the adaxial sclerenchyma forming girders; the abaxial sclerenchyma forming girders; the combined girders forming I's. Outlines of lower order vascular bundles more or less circular. Lower order vascular bundles centrally situated; with adaxial sclerenchyma, or without adaxial sclerenchyma; with abaxial sclerenchyma, or without abaxial sclerenchyma; the adaxial sclerenchyma ,when present, forming girders; the abaxial sclerenchyma ,when present, forming girders, or forming strands; the smallest vascular bundles lacking sclerenchyma. The adaxial sclerenchyma of the mid-lamina all associated with vascular bundles.

Cytology. 2n = 14.

Distribution. Endemic. New South Wales.

Ecology. Distribution by vegetation region: temperate sub-humid grasslands. Flowers Nov.-Jan.

Vouchers. Specimens examined morphologically: P.Michael s.n.: Mt Cooper, 16 mls. from Nimmitabel (N.S.W.); 18.i.1961; Fr. Anat. 1545; CANB - R.Pullen. 11079: c. 15 km W. of Nimmitabel along rd. to Dalgety near Coopers lake (N.S.W.); 12.i.1984; Fl., Fr. Anat. 1193; CANB - J.H.Willis s.n. MEL 626859; E. Gippsland, Wulgulmerang (C. 70 km NNW. of Orbost), rocky slopes along Boundary Ck, near Junction Falls Ck (Vic.); 28.xi.1962; Fl.; MEL - R.Melville 3011: Little R., Wulgulmerang, c. 33 mls. NNE. of Buchan, Gippsland (Vic.); 20.i.1953; Fr.; MEL - J.H.Willis s.n. MEL 502456: E. Gippsland, Mt. Tingiringi (N.S.W. border), 0.5 mls. NE. of summit, 4100 ft (Vic.); 30.xi.1962; Fl. (pre.); MEL.

Material examined anatomically: R.Appels CSIRO Jan. 1987 RSBS 1329; R.Pullen 11079, Coopers Lake, NSW. RSBS 1193; Steinhauser; P.Michael s.n. NSW RSBS 1545 ;Bänorlen; White.

Classification. Triticodae; Triticeae.

In this work A. retrofractum is treated in the sense of Vickery (1951), and is not placed within A. pectinatum as proposed by Simon (1986), nor is it considered to include A. velutinum at subspecific rank as circumscribed by Löve (1984).

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