Splendid isolation

March 16, 2020

In a welcome break from the recent news cycle, I spent much of the weekend out of cellphone range in the Eyre Mountains; whilst showing 2 colleagues from a UK-based project around various sites in Wellington and Southland. Our visit turned out to be very well-timed, with Southland’s weather on best behaviour for 2 days spent observing interesting landscapes and native plant communities in that region.

We were fortunate to be spending both days within Southland in the company of one of the foremost experts on that region’s flora (especially montane species), Steve Newall. Whilst the opportunity to explore the Eyres was a novel experience for us, Steve has gained a comprehensive knowledge of this range (and in fact much of the South Island’s mountainous areas) over decades of botanising and working with plants.

During the long walk up the river valley, we came across large specimens of one of our small-leaved tree daisies (mostly associated with southern parts of the country) – in this case, possibly Olearia lineata (pictured at the top of this entry).

It was valuable to see the expressive branching that develops on very old specimens of this and related species (such as O. fimbriata and O. virgata), as I had never observed plants of this age range within the wild. Their gnarled form is a characteristic that was firmly in mind when specifying Olearia fimbriata within a recent design for a Central Otago project.

After several hours of walking upstream along Eyre Creek, where the vegetation was relatively even in character (consisting of exotic grassland and native shrubland, dominated by Coprosma propinqua, Corokia cotoneaster and Discaria toumatou), we turned abruptly uphill.

In contrast with the river valley and its adjoining sections of beech forest, open montane communities like those that grow amidst shattered rock on the exposed mountain slope change frequently as one ascends. In upper parts of the hillslope, broad patches of snow tōtara (Podocarpus nivalis, pictured above) are a dominant element – around (and within) which other plant species find opportunities to grow.

At the point where the exposed slope rolls over to a slightly more sheltered aspect, vegetation of a different character takes hold, including the ferocious species of spaniard (a distinct form affiliated with Aciphylla horrida, tag named Aciphylla ‘Lomond’, shown above) and a spectacular species of mountain daisy called Celmisia semicordata subsp. stricta.

The diminutive species of native ‘puha’ shown above cuts a much less threatening figure where it emerges from the bare rock. Seeing Sonchus novae-zelandiae in the wild was thoroughly unexpected on this trip, due to its rarity – with this dryland species officially classed with the threat ranking, ‘Nationally Vulnerable’.

Marking the point where we decided to turn back towards our vehicles was the endemic Eyre Mountains Daisy (Celmisia philocremna); one of the main species that we hoped to encounter. This vibrant green mountain daisy is a somewhat anomalous sight amidst the comparatively muted hues of surrounding plant and lichen species (as well as the distinctly mineral, fawn colour of this apron of shattered rock).

Residing in the uppermost reaches of the mountain, C. philocremna is a strange beast; with the appearance of an over-sized cushion plant that can’t quite decide whether it’s going to go the whole hog and take on a growth form like its more hardcore compadres, Raoulia buchananii and Helichrysum intermedium.

That said, it’s in good company with the nearby occurrence of another mountain daisy that seems to be doing its best to look like a spaniard (Celmisia lyallii, in the centre of the photo above). In the case of this striking species (which is known by the common name of ‘false spaniard’), convergent evolution truly is a wonderful thing.