Australopyrum retrofractum (Vickery) Á.Löve
Leaf-sheath 4-5 cm, coarsely pilose with long dense retrorse or mixed hairs, striate. Auricles 1.0 mm, clasping, glabrous. Ligule 1.5 mm, erose, glabrous. Collar white, margin sparsely hairy. Leaf-blade 3-6 cm × 2 mm, rough, hairs coarse long (0.5 mm) and shorter, margin long-hairy, prow-tipped. Culm 10-25 cm, internodes glabrous, nodes evident some geniculate, inflorescence node with long soft hairs. Inflorescence a spikelike raceme 2-5 cm, spikelets c. 6, rachis retrorse hairy on margin, elsewhere hairs mixed, internodes c. 2 mm. Spikelets to 15 mm, florets 4-8, ± appressed broadside to rachis; pedicel 0.5 mm, hairy. Glumes ± unequal, 6-8 mm, nerves 1-3, indurate, shining, glabrous, becoming reflexed, swollen at base, awn-like above, linear triangular, asymmetrical, adaxially with short white hairs, margins chartaceous. Lemma 7.5-10 mm, narrowing into glabrous shining indurate awn ± 4 mm, keeled, ± glabrous or with scattered prickle-teeth, adaxially with short white hairs above, margin chartaceous. Palea 5-6 mm, denticles long and stout on upper keels, interkeel with few short white hairs. Callus 0.15 mm, broad, disarticulation flat. Rachilla 0.75 mm, finely short stiff hairy. Lodicules 0.7-0.8 mm, hairy. Anthers 0.7-1.5 mm. Gynoecium: ovary 1.0 mm; stigma-styles 2-2.5 mm. Caryopsis c. 4 mm; embryo 0.6 mm; hilum = caryopsis.
N.: Hawkes Bay, T. Kirk 1202; S.: inland Marlborough; inland Waitaki and Central Otago basins.
Naturalised from Australia.
See Jacobs, S. W. L. Telopea 3: 601-603 (1990) for discussion on the correctness of the binomial A. retrofractum.
Cockayne, A. H. N.Z. J. Agric. 3: 1-8 (1911) and Petrie, D. N.Z. Dept Agric., Ind. Comm. Bull. No. 23 [i.e. 28] (1912) recorded this species from several localities in Central Otago, and the Waitaki Valley; in Marlborough Cockayne (1911 op. cit.) listed it as present on Upcott, Middlehurst and Molesworth stations in the Awatere Valley. In all these places it was said to be well established on badly depleted semi-arid areas. Modern records indicate that there are now no well established populations at any of those sites. Other than T. Kirk 1202, no plants referrable to A. retrofractum have been seen in North Island.
Plants referred to A. pectinatum by Hamilton, A. List of the genera and species of New Zealand plants (1899); Cheeseman, T. F. [Man. N.Z. Fl. (1906), Man. N.Z. Fl. (1925)]; Cockayne, A. H. (1911 op. cit.); Petrie (1912 op. cit.); Thomson, G. M. The naturalization of animals and plants in N.Z. (1922); and Allan, H. H. N.Z. DSIR Bull. 49 (1936), N.Z. DSIR Bull. 83 (1940), are A. retrofractum.
Hamilton, A. (1899 op. cit.) listed Agropyron velutinum (currently Australopyrum) as present in New Zealand, but we can find no supporting evidence.
GENOME ANALYSIS
Australopyrum, the only diploid triticoid in Australasia, to which Löve (1984 op. cit.) had allocated the genomic formula W, has contributed that genome to Australasian hexaploid species of Elymus [Torabinejad, J. and Mueller, R. J. Genome 36: 147-151 (1993)]; that association is unrecorded in Kellogg et al. (1996 op. cit.).
