This article was published in The Fringe, May 2016
Taurepo, Matata, Waiuatua, New Zealand Gloxinia.
Rhabdothamnus solandri, is the only member of the genus Rhabdothamnus and is part of the tropical family called Gesneriaceae.
That makes it a monotypic genus, endemic to New Zealand, and a special plant, but sadly, also one that is little known. Although relatively common, particularly in the Waitakere Ranges, it is seldom noticed and rarely referred to in reference books. It is not a tree therefore misses out entirely in books on NZ trees. Being a single species with no near relatives it does not feature prominently in books about shrubs, and having a particular niche habitat it is missing from large areas of our forests. Furthermore, it is not so threatened that it is mentioned in articles and books on endangered plants.
If you have it growing on the steep rocky slope behind the house, or down the slope to the stream, do learn to love it, not just for its interesting look and beautiful flowers, but also for its singularity. The Gesneriaceae are a widespread family throughout the world and the largest genus is the Cyrtandra which occur throughout Asia and the Pacific, but no members of the Gesneriaceae grow in New Zealand, other than Rhabdothamnus.
Taurepo got off to a good start in the history of NZ botany having been first recorded by Banks and Solander in 1769 on Captain Cook's first voyage when they arrived at Mercury Bay. But it was another 57 years before being noted again by Allan Cunningham in the Bay of Islands. Today the Auckland region appears to be its stronghold although it does occur less frequently throughout the North Island.
Taurepo prefers free draining, rocky yet fertile sites particularly on limestone karst formations. It is a 2m shrub with harshly hairy leaves arranged in opposite pairs and a conspicuous red/orange tubular flower. It is the structure of the flower that is critical to the future of the plant. While it seems to be capable of self-pollination, it is reliant on birds to provide the cross-pollination necessary for the best genetic strength and variability.
Therein lies the problem as the main pollinating birds are only now starting to recover with all the pest control we have put in place in recent years. There are extensive areas of the North Island where one or more of the bellbird, tūī, and stitchbird are absent, and even worse the huia is of course extinct. So the natural niche that each bird fills is vacant and plant species reliant on them for pollination and perhaps seed dispersal suffer accordingly.
In the millennium that Rhabothamnus has been isolated in New Zealand it has started to evolve and the hint of new species can be seen where the conditions are such that a degree of adaptation is necessary for the species to tolerate them. On Maunganui Bluff in Northland, Rhabdothamnus has evolved into a densely bushy form with quite scabrid hairs on the smaller leaves which provide extra protection against the salt spray and wind to which it is exposed. At North Cape there is a similar but different adaptation where some plants exhibit small leaves but have chosen to grow as a vine or groundcover that can escape the winds by merging into the surrounding vegetation. Perhaps another adaptation is the flower colour where it ranges from shades of dark red in the North Island to a yellow-coloured form on off-shore islands on plants with distinctly larger leaves.
Not the easiest plant to establish, but in the right place it will flourish with very little attention for many years.