I spent a couple of days of the long weekend with the Wellington Botanical Society, exploring the Foxton area, between Whanganui and Palmerston North. Much of the first and second days were spent in the sand dunes between Himatangi and Foxton Beach, and at Koitiata near Turakina.
A huddle of prostrate people peering intently at the ground; can only mean a botanical society has fixated on some small plant. Photo © Leon Perrie.
Many of the plants in the wetter parts of the dunes are very small. This is mudwort (Limosella lineata). Photo © Leon Perrie.
Arrowgrass, Triglochin striata, is not actually a grass, and belongs to the unusual monocot family Juncaginaceae. The arrangement of the flowers and the narrow leaves are distinctive. Photo © Leon Perrie.
Intermixed Selliera rotundifolia, with the round leaves, and Lilaeopsis novae-zelandiae, with the jointed linear leaves. Selliera rotundifolia is only found in the south-west of the North Island. Photo © Leon Perrie.
The tiny Isolepis basilaris is distinctive in holding its inflorescences amongst its leaf bases, near ground level; see just below the image’s centre. Immediately behind are the small, oval leaves of Myriophyllum votschii. To the rear are the green oval fruit of Selliera rotundifolia, whose leaves flank the image’s left and right. Photo © Leon Perrie.
The dunes are also home to larger plants. This is the sand daphne (Pimelea villosa). It has a conservation status of Declining because of ongoing damage to sand dunes and apparent seed-set failure. Photo © Leon Perrie.
Close-up of the flowers of sand daphne. With its abundant hairs, it is easy to see the relevance of the recently reinstated species name, villosa (= covered with soft hairs). This was previously known as Pimelea arenaria. Photo © Leon Perrie.
Some surprising things can become weedy in the sand dunes.
Formosum lily (Lilium formosanum), from Taiwan, is abundant in the dunes around Foxton Beach. A pretty problem. Tree lupin (Lupinus arboreus), with yellow flowers, is the bush behind and is also a weed. The orange stems in the foreground belong to the native knobby club rush (Ficinia nodosa). Photo © Leon Perrie.
An exotic Fuchsia in the sand dunes at Koitiata, near Turakina. Just one or two plants were seen. Does anyone know what species/cultivar of Fuchsia this is? Photo © Leon Perrie.
One plant of what I think is French lavender (Lavandula stoechas) in the Koitiata dunes. © Leon Perrie.
The ‘Red Apple’ cultivar related to Aptenia cordifolia (thanks to Colin Ogle for the identification), from South Africa. This is in the same family as our native iceplants. A couple of patches of Aptenia ‘Red Apple’ were established next to a garden-discard site in the dunes at Koitiata. Photo © Leon Perrie.
Pumpkin had also self-established next to the Koitiata garden-discard site. Several fruit were harvested, albeit for nutrition rather than science. Photo © Leon Perrie.
A few plants of the aristea iris (Aristea ecklonii) were found in the Koitiata sand dunes. The species is already a menace in Northland, and hopefully it doesn’t become as abundant in the southern North Island. Photo © Leon Perrie.
Weeds also caught our attention elsewhere.
The abundant pom-pom daisy heads of wavy leaved fleabane (Conyza bonariensis) caught my eye in the carpark of Round Bush/Omarupapako, where it was growing in the gravel with the related broad leaved fleabane (Conyza sumatrensis), which I’m more familiar with. Photo © Leon Perrie.
Wavy leaved fleabane (Conyza bonariensis) has larger daisy heads than broad leaved fleabane (Conyza sumatrensis). Additionally, the inflorescence bracts of wavy leaved fleabane are tipped red, which can be clearly seen in the image, compared to green in broad leaved fleabane. Photo © Leon Perrie.
The botanical society did not progress far through the tangled swamp forest vegetation of Round Bush/Omarupapako Scenic Reserve. However, we went far enough to encounter karaka (Corynocarpus laevigatus) and to debate its merits in the southern North Island, where some people consider it to be weedy. The large trunk at centre is a podocarp, while the trunk to the immediate left is a tall and reproducing but not particularly old karaka. Karaka seedlings are evident in the foreground. Photo © Leon Perrie.
Water purslane (Ludwigia palustris), at Lake Koitiata, was new to me. I identified it using David Glenny’s Key to Flowering Plant Genera of New Zealand. Photo © Leon Perrie.
David Glenny’s (Landcare Research) Key to Flowering Plant Genera of New Zealand.
We found the exotic ferny azolla (Azolla pinnata) at Lake Koitiata. Normally this floats, but it had become marooned in the mud with the summer-lowered water levels. This is only the fourth record of this invader in the southern North Island. Photo © Leon Perrie.
How to distinguish the native Azolla rubra from the weedy Azolla pinnata, and how you can help track their distributions.
Botanical Society trips are a great way to learn how to distinguish plants. I certainly learnt a lot during this trip, and thanks to all those who took part and shared their knowledge.
Contact details for local botanical societies in New Zealand.