Australopyrum calcis subsp. optatum Connor & Molloy
; Holotype: CHR 468526a! B. P. J. Molloy FH 1a Canterbury, Flock Hill, above cave, Cave Stream; 780 m, 23 Jan 1991.
Shorter and finer than typical subspecies. Leaf-blade shortly toothed on ribs; culm internodes glabrous; rachis glabrous but margins toothed; lemma abaxially shortly stiff toothed.
S.: North Canterbury: inland at headwaters of Waimakariri River, slopes of Mt Torlesse, Castle Hill, Flock Hill, Prebble Hill, and coastal at Mt Cass. Sparse grass-herb communities on skeletal to weakly developed soils at shaded bases of overhanging limestone tors; 500-900 m.
In cultivation the differences between subspecies are maintained.