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Diagnostic features for identification in the field

Blue Wheatgrass Tussocks

(elybot2)

These tussocks are very palatable. In grazed areas, they may only occur as small inconspicous tufts within other less palatable plants, such as matagouri or hard tussock. However, where grazing pressure is low, large conspicuous tussocks can be found.

(i)Elymus apricus

Restricted to Central Otago valleys

  • A medium sized golden-green tussock with leaves to 30cm long.

  • Long flower stalk with curved awns on seeds

(ii)Elymus solandri

Recently renamed; used to be known as Elymus rectisetus

Found throughout South Island.

  • Highly variable appearance

  • Pale-green to blue-green tufts

  • Distinctive flower heads of up to 10 spikelets, in which the 5 - 12 florets have very long slender awns.

Rytidosperma species

(rytbot2)
    Rytidosperma clavatum

  • A small lax tussock, with leaves to 15 cm long and 2mm wide. hairy above, and sparsely hairy below. The sheath is densely hairy or hairless.

  • The ligule has a dense bunch of long hairs.

  • The flower stalk can be to 90cm tall; not hairy, with a branched flower head.

  • Long bent awn; rough to touch.



References:
  • Mark A.F. and Adams, N. 1996. New Zealand Alpine Plants. Reed Methuen.
  • Jane, G. 1995. 1995, Field guide to grasses. 1.Alpine grasses.

Description of community and habitat

Elymus apricus tussock grassland of the Central Otago valleys is now virtually extinct, due to it's palatability to stock. Where stock and rabbit numbers are low (e.g. Flat Top Hill reserve; eastern side of Manuherikia River), these tussocks occur with other species of Elymus tussock and Rytidosperma clavatum, especially on free draining gravelly slopes, and at the bases of rocky outcrops.

Other species present

Elymus apricus and Rytidosperma clavatum occur with natives such as blue tussocks, Lepidium species, a rare cress, and broom (Carmichaelia compacta). Exotic plants include hare foot's trefoil (Trifolium arvense), Kentucky blue grass (Poa pratensis), Aira caryophyllea, Vulpia bromoides, thyme (Thymus vulgaris), woolly mullein (Verbascum thapsus) and Vittadinia australis.

Vegetation History

 The Central Otago region has a complex history of disturbance. Post-glacial forest may never have extended to the drier basin of Central Otago, and the establishment of grassland, possibly through natural fires, preceded human settlement by several centuries (Wardle, 1985; McGlone, 1989; McGlone et al., 1995). Human impact since Polynesian times has led to changes in soils and vegetation. those changes brought about by pastoral use of the land since European settlement may be traced from early (e.g. Buchanan, 1868; Zotov, 1938) and recent descriptive accounts (e.g. Wardle, 1963, 1985). Degradation has often been blamed in the rabbit pest, which can reach plague proportions, although burning and overgrazing by sheep and feral goats have also contributed.

Information taken from: Walker, S; Mark, A.F., and Bastow Wilson, J. 1995: the vegetation of Flat Top Hill: an area of semi-arid grassland/shrubland in Central Otago, New Zealand. NZ Journal of Ecology, 19(2): 175-194.



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