Forest Vines to Snow Tussocks: The Story of New Zealand Plants
Notable among the large alpine herbs are the Spaniards or speargrasses belonging to the genus Aciphylla of the Umbelliferae (carrot family).138 Nothing could look more unlike a carrot plant than the larger spaniards of tall tussock grassland. In their tussock-like clumps the large leaves are deeply divided into hard, rigid segments tipped by needle-sharp spines. The flower, and later seed, heads are equally unusual in that, instead of being broad and open as is more typical for the family, they are dense, narrow and lance-like. The individual flower clusters, densely aggregated on the upper parts of the lances, are exceeded in length by their associated bracts. These bracts have segments as spiny as those of the leaves. Having suffered while collecting specimens of such spaniards page 175for study, I am inclined to agree with the suggestion that the excessive spininess is a defence against browsing animals (and botanists), which in pre-human times in New Zealand would have been the moas. However, despite their unpleasant characteristics, many of the spaniards are striking in appearance and, when strongly coloured, decidedly handsome as well. Some species have grey-green leaves and flower heads ranging from green to pale yellow, others have both leaves and flower heads with a quite strong yellow to orange colouration as, for example, in the golden spaniard (Aciphylla aurea) (Fig. 98).
Figure 98 The golden spaniard (Aciphylla aurea) scattered through tussock grassland comprised of narrow-leaved snow tussock (Chionochloa rigida). Mt. St. Bathans, Otago.
Photo: J. W. Dawson.
The golden spaniard, A. aurea, is often prominent in drier habitats in the eastern South Island and is characteristic of narrow-leaved snow tussock grassland (Fig. 98). In higher herbfield where the plant cover is shorter the larger species of Aciphylla give way to smaller forms. Some of the smaller forms are spiny with narrow inflorescences; others are more like the related Anisotome with soft leaves and broad inflorescences.
It is difficult to understand why narrow dense inflorescences should have evolved in Aciphylla. It could be seen as a protective device as the short flower clusters are readily shielded by the spinescent bracts, but similar (although not spiny) inflorescences occur in quite unrelated plants elsewhere in the world — the tree Senecios and Lobelias of the central African Mountains, the Puya (Bromeliaceae) of the northern Andes, Echium in the Canary Islands and the grass trees (Xanthorrhea) in Australia, to name a few.