Friday, 30 December 2011

Wandering Willy

One of the worst weeds in disturbed bush remnants (and some barely tended gardens I'm a bit familiar with) is wandering willy, or Tradescantia fluminensis.  The genus is found in North and tropical America and is named after John Tradescant, who was gardener to Charles the First.  (First aside: there's a family story that we're descended from Col. John Jones, who married Oliver Cromwell's sister and signed Charles's death warrant, but I've been unable to verify it and for several reasons it seems unlikely.) (Second aside: Philippa Gregory's two historical novels about the Tradescants, Earthly Joys and Virgin Earth, are good reads.)
Tradescantia fluminensis
Wandering willy used to be called wandering Jew in New Zealand, but that's considered offensive, and along with similar common names like wild Irishman and Spaniard has largely disappeared. I'm not sure that puritans, like Cromwell and others of his time, would have approved of wandering willy either.

Tradescantia is flowering well this year.  At least I think it is, but I don't have quantitative data to verify my impression.  Normally I'm aware of occasional flowers, but this year I've noticed a lot of flowers.  It'll be interesting to look for fruit later.  It's not easy to verify such impressions without counting and measuring, and that requires keeping a notebook year after year.

Tradescantia is a serious weed because it's rapidly spread through fragments of stem that can root easily.  Almost any attempt to control it manually is destined to just spread it further (at least that's my excuse for letting it run rampant in my garden).  And of course avoiding tip fees by dumping garden rubbish in gullies and on roadsides just spreads weeds further.

Thursday, 29 December 2011

Urban forest remnants; the balance between planting and killing

Wellington abounds with small forest remnants in gullies and on hillsides, most of them second-growth.  Many of them have dedicated "friends" groups that plant and weed to encourage the natives and discourage the invaders.  My local patch is the Birdwood Reserve, which is continuous with its more glamorous neighbor the Karori Wildlife Sanctuary, now rebranded as Zelandia.

Kaka, Birdwood reserve.

Birdwood Reserve is kohekohe/titoki/mahoe forest, with some kotukutuku thrown in and a lot of kawakawa in the understory.  Tui and kaka are the common native birds, along with fantails and silvereyes.  Once I saw a tieke.  There are a few big cherries and sycamores that'll have to be removed some day, and some agressive introduced climbers, particularly old man's beard.  Around the edges it suffers the usual urban fates of rubbish dumping, landslides, clearing, and vandalism; there are road cones, a bicycle, a bathroom sink, roofing iron, and old election hoardings flung down the bank.

Sprayed understory, now collecting weeds and rubbish.
A few years ago I started planting out there a few natives (mahoe, ngaio, rangiora, matipo, makomako) that had come up in odd corners of my garden where wind or birds had dropped the seeds.  Each year I'd plant out a dozen or so, and a few of them are now quite big.  But each year someone would decide the area needed tidying up, and would organise for the weeds along the paths to be sprayed.  Whenever this happened I'd lose about half my plantings to spray drift.

Spraying has yellowed the leaves on this planted karamu (Coprosma robusta), but the orange-flowered Tropaeolum majus  appears unharmed.
Worse than that though, the spraying has eaten into the original bush edge, mostly by killing off the kawakawa, which is particularly sensitive, so that the area needing replanting keeps getting bigger.  The understory and bush margin dies, then the wind gets in and tears branches from the trees.  It's a steep bank, and prone to slips after heavy rain; there have been two quite big ones in recent years, both following vegetation clearance.  Before you know it, weeds, especially wandering willy, have invaded under the trees, so that next year's tidy-up has to go further from the path.  In places, where once there was a sharp and impenetrable bush edge at the path, there's now an ugly bare and dying area, and you can see 10–20m into the bush.

Spraying has isolated a titoki and a mahoe (left) by opening a gap right through the forest where once was dense undergrowth.
I've tried to discuss this with the Council.  They were concerned and helpful.  But my impression is that the team that manages reserves is different from the team that manages weeds.  In response, the council generously offered to provide me with more plants, free from their own nursery, if my group (i.e., me) would plant them.  But I don't see the point of planting more until the sprayers are brought under control.  And as a ratepayer, I also don't see the point of raising plants in a nursery, planting them out, and then killing them.

Sprayed Crocosmia xcrocosmiiflora.  Vandals repeatedly damage the fences, pushing over posts and ripping off the rails.

The plant names

Prunus spp.
Piper excelsum
Dysoxylum spectabile
Fuchsia excorticata
Melicytus ramiflorus
Aristotelia serrata
Myrsine australis
Myoporum laetum
old man’s beard
Clematis vitalba
Brachyglottis repanda
Acer pseudoplatanus
Alectryon excelsus
wandering willy
Tradescantia fluminensis

Thursday, 8 December 2011

Is there a lower limit to flower size?

How small could a flower get?  In a previous post I mentioned New Zealand's smallest flower, Wolffia arrhiza.  The smallest New Zealand flower that has a corolla and so looks like a flower however, is considerably bigger (Myosotis brevis, at 1 mm diameter).  But what's the smallest a flower could be?

Most flowers are hermaphrodite, but there are plenty of flowers that are either male or female.  But for the sake of argument, let's say our flower must be hermaphrodite.  It needs a pistil and at least one stamen, but maybe it doesn't need petals (corolla) and sepals (calyx).

The pistil is the female part of the flower.  Let's keep it as simple as possible, a single carpel with a single ovule (the ovule becomes the seed).  The carpel is a modified leaf, and its wall needs an epidermis on each side (say 10 µm thick), and a minimum of 1–2 layers of mesophyll in the middle, cells that are probably at least 15 µm ; that's a layer 4 cells in thickness (say 50 µm ) wrapped around the ovule.  The ovule can have a single integument if it's an Asterid (other flowering plants have 2 integuments), maybe 2 cells in thickness.  Inside that is a single layer of nucellus (megasporangium wall), and inside that an embryo sac of 7 cells.  The whole ovule could be shrunk down to about 100 µm (the lily ovule featured in first year textbook Raven Evert & Eichhorn is about 400 µm across).  The ovule needs a vascular supply, but it it's orthotropous (erect on its stalk) the thickness of a vascular bundle doesn't need to be added to the flower's diameter.  So the single ovule surrounded by  carpel wall could be about 200 µm diameter.

The stamen could similarly be reduced.  If this tiny flower is cleistogamic, maybe it doesn't need complex walls like a lily stamen has (200 µm thick).  Maybe 50 µm is enough, like the carpel wall.  The smallest pollen grains are about 10 µm , and even a cleistogamic flower will need more than one of them.  Firstly, because pollen grains develop from spores, and spores are produced by meiosis, 4 would be a theoretical minimum (without abortion, such as happens in the ovule).  Secondly, even a habitual self-pollinator needs an excess of pollen grains to ovules, maybe 20–30:1 at a minimum.  The internal volume of the anther couldn't be much smaller than about 30 µm diameter; adding the wall on both sides would make it about 130 µm across.

Such a flower doesn't have to have the pistil and stamen packed side by side.  If the ovary of the pistil overlapped the filament of the stamen, and the anther of the stamen overlapped the style of the pistil, they could fit together into a smaller space.  The resulting flower is about 230 µm diameter, a pretty good match for Wolffia arrhiza at around 250 µm.

Friday, 2 December 2011

Diggers' speedwell

People are starting to get used to the idea that the hebes and parahebes of New Zealand really do belong back in the genus Veronica, where they were first classified by Forster after Cook's second voyage.  Our 120+ species of shrubby hebes, subshrubby speedwell hebes & sun hebes, and cushion plant snow hebes are an amazing group of plants that have diverged from the standard northern veronicas in many different ways.  They're classified now as Veronica section Hebe, and their sister group (with a shared ancestor in common) is the Australian Veronica sect. Labiatoides.

Diggers' speedwell is one of these Australian veronicas (Veronica perfoliata).  It grows in south-eastern Australia and it's occasionally cultivated in New Zealand.  This rather straggly plant has been growing in a pot, but given a good spot in the garden it will adopt a nice rounded form from a bunch of new shoots that arise from the rootstock each spring.  The leaves are very Eucalyptus-like, bluish green and very firm, and joined in opposite pairs to surround the stem—that's what perfoliate means.  In fact if you saw it when not in flower, you'd probably think it was a gum tree seedling.

The flowers are a strong mauve colour, with a little pink surrounding a dense tuft of glassy hairs in the centre.  These long glassy hairs are found in quite a few of the Australian species (like V. derwentiana and V. nivea), but we don't see anything like them in New Zealand Veronica.  It's easy to propagate from cuttings.  You can cut the stem up just above every pair of leaves, so each internode makes a good cutting.

Just as our veronicas have evolved away from the northern type here in New Zealand, so have their relatives in Australia.  The similarity to a eucalypt isn't an accident; such sclerophyllous leaves are adaptive in the Australian environment and common in many unrelated plant groups.

Saturday, 26 November 2011

Introducing the herbarium

A herbarium is one of the main tools for research and documentation of plant biodiversity.  It sounds like a garden, and in fact an old name for a herbarium is hortus siccus, or dried garden.

A herbarium is a collection of dried and pressed plant specimens.  The first herbarium is thought to have belonged to Luca Ghini, an Italian professor of botany, in the 16th century.  Early herbaria were kept in bound books, but mounting each specimen on a separate card—we call them "sheets"— means the specimens can be rearranged and studied separately, and it minimises damage.

The specimens are pressed only to keep them flat while they dry.  It's the drying that preserves them.  The best specimens have all the plant parts represented, so they can be studied, but this gets tricky with large plants.  With palms and tree ferns, where a single leaf can be several metres long, there are compromises to be made.  Kept dry and free of pests, a herbarium specimen can last for hundreds of years.  Several New Zealand herbaria have specimens collected on Cook's first voyage in 1769, and they're still in good condition.

The label on a herbarium sheet is very important.  It identifies the plant, tells where it was collected (now with GPS reference), what habitat it was growing in, who collected and identified it, and when, and provides notes (e.g., flower colour, abundance, scent, etc.).

The main advantage of a herbarium is it brings a large sample of different species together in one place where they can all be compared.  And it brings a large sample of individuals together too, sampled from different locations and different habitats.  While field work is important in biodiversity, the detailed research and discovery often takes place in the herbarium.  I remember sorting buttercup specimens (Ranunculus) with the late Tony Druce in the late 1970s.  We found an odd specimen in the Ranunculus hirtus folder that we thought might be an unidentified introduced plant.  Among the specimens of the next species we looked at, we found another, similar, one.  By the end of the day we had a pile of specimens of what we were now sure was an unnamed native species, now called R. altus.  It's a common plant on montane forests of the South Island, on disturbed sites like old landslides.
Ranunculus altus at Rough Creek, Arthur's Pass National Park.
We use herbarium specimens all the time in taxonomy.  Most often we use them as references to check our identifications.  In very critical cases, we can go back to the type specimens, which define the usage of a name.  We also use them when we describe species for publications.  We can even extract chemicals, including DNA, from herbarium specimens for study.

Another important role for herbaria is to document observations.  Let's say I observe red admiral butterflies pollinating Veronica stricta.  I can report that in a scientific paper, but how can the reader be sure of my identification?  If I collect a specimen of the actual plant, then even if I'm wrong it can be checked and if necessary corrected.

Modern herbarium label data are becoming databased, so that on line searches for information are increasingly possible.  Thus we can map distributions, and compare these with other information in geographic information systems.  Traditionally, herbaria have been organised taxonomically, following the scientific classification system, but databasing allows information to be assembled using other parameters, like location, habitat, flowering times, or growth forms.  If you cared, you could generate a list of dicotyledon trees growing in Canterbury above 500m altitude that flower in January.

New Zealand has three large herbaria, at Landcare Research, Te Papa, and the Auckland Museum.  There are smaller ones at other research institutes and universities.  They collaborate through the New Zealand National Herbarium Network. Overseas, there are many much bigger collections, like those at Kew, Paris, Berlin, St Louis, and New York.  The herbarium is an essential tool for studying and documenting plant diversity, and a valuable resource for its conservation.

Wonderful as they are, herbaria have their imperfections and problems, which I intend write about in future blogs.

Friday, 11 November 2011

Hayfever (allergic rhinitis) time

I love it when the spring winds die away and the warm days of summer arrive.  But I hate it too, because when Dactylis glomerata flowers, my life becomes miserable.  I'm allergic to its pollen, and a bit less so to the pollen of a bunch of other grasses and wind-pollinated trees and herbs: oaks, chenopods, and plantains.
Cocksfoot, Dactylis glomerata, Wellington, NZ.

Dactylis glomerata, or cocksfoot, is a major pasture grass and weed in New Zealand. Its pollen is abundant from early November until the first week of January (I'm a walking bioassay) and again with a minor peak in March.  In 1990, we bought a house in Okuti Valley, Banks Peninsula (this one), only to discover after we'd moved in that this valley used to be the cocksfoot seed growing centre of the known universe.  It was Hell.

My first hayfever attack happened when I was about 9 or 10.  My brother and I were playing outside with toy bombs that carried percussion caps, which exploded when you dropped them.  (Fifteen years after WW2, these military toys were still very popular.) So we both reported in with itchy eyes and the parents assumed it was to do with the gunpowder in the caps.  They called the doctor—doctors used to visit, on Saturday afternoons too, in those days— and we were sent to rest in darkened rooms.  It was some time later they realized it was hayfever.

The TV advertisements for hayfever remedies always feature showy flowers: lilies, daisies and the like.  But hayfever is an affliction caused by the insignificant flowers, the ones that are wind pollinated.  Wind pollinated flowers have a rather haphazard method of dispersing their pollen; it's random and inefficient and so they need to produce a huge  number of pollen grains for every ovule.  They're insignificant because they don't need to attract a pollinator with showy petals and scents.  But they fill the air with their pollen and it gets up our noses.

Insect- and bird-pollinated flowers have a much more efficient mechanism for dispersing their pollen, one that delivers it reliably to another flower.  Because it's so much more efficient, they don't need to produce so much pollen, and it's not out there in huge amounts causing misery to folks like me.

You might think I'd hate all grasses.  I have to admit I don't find them very interesting. But I do like this genus, Briza:

It sucks to be a botanist who's allergic to flowers.

Tuesday, 8 November 2011

How small can flowers get?

A few weeks ago, I blogged about the plants we saw on a short walk along the coast south of Makara.  This week, I had the opportunity, courtesy of Meridian Energy, to visit two bays a bit further south.  I was with Heidi Meudt (Te Papa botanist), Jessie Prebble (PhD student), and Ewen Robertson (Environmental Compliance Specialist with Meridian), and we were looking for one of New Zealand's smallest plants.

Te Ikaamaru Bay and Ohau Bay are on Terawhiti Station, but access by road and 4WD track is through Meridian Energy's wind farm of 62 giant turbines.

Much of Terawhiti Station is returning to forest, and the intermediate stages are dominated by mostly native shrubs: manuka (Leptospermum scoparium), tauhinu (Ozothamnus leptophyllus), Olearia solandri, coprosmas, and small pockets of introduced gorse and Darwin's barberry.  Pale yellow native clematis was prominent among the scrub. Goats are common, and the understory commonly features the giant nettle ongaonga (Urtica ferox).

Te Ikaamaru Bay
The tiny plant we were seeking is Myosotis pygmea var. minutiflora, now treated by many botanists as a separate species, Myosotis brevis.  One of the aims of Heidi and Jessie's research is to test whether it's a "good species", that is, whether the evidence indicates it's a separately-evolving lineage from its relatives.

Like many native forget-me-nots, it's rare, though it's easy to see why it's often overlooked, so it might be more common than we think.  We had records of it growing in both bays, on coastal turf of Selliera radicans and Leptinella dioica.  And that's just where we found it, wherever the soil was a bit peaty.

Myosotis brevis
Myosotis brevis is so small that you need to first find the habitat, then get down on your hands and knees to find it.  Even then, we might have missed it but for the tiny—no, minuscule—flowers (the world's smallest flower is the tiny duckweed, Wolffia, where the whole plant is about 1 mm across and the flower is about 0.25 mm).
Myosotis brevis, the flower is about 1 mm across.
Forget-me-not flowers are mostly blue in other parts of the world, but nearly all of ours are white, cream, yellow, or rarely brownish.  Interestingly, there are two blue-flowered ones in the Subantarctic Islands, where other plants have brightly coloured flowers too. The creamy flowers of M. brevis are about 1 mm in diameter.  Do they self-pollinate, or is a tiny pollinator required?

On the cliffs at the headland, we found some Peperomia urvilleana.  This tiny pepper relative makes a good indoor plant, but here it thrives in the open, exposed to salt spray.
Peperomia urvilleana
The oystercatchers were making a racket.
Oystercatchers among cape weed, Arctotheca calendula.
No wonder; they were sitting on their second clutches of eggs. I saw one ferret, so I guess life's tough for oyster-catchers.

There were plenty of other native small-flowered plants, like Limosella lineata...
Limosella lineata
... Dichondra repens, here being visited by an ant, ...
Mercury Bay weed, Dichondra repens
... and Colobanthus muelleri (seed capsule top centre).
Colobanthus muelleri
An odd plant for me, because I had only seen it once before, was a thistle-like member of the carrot family (Apiaceae).  This is Eryngium vesiculosum.
Eryngium vesiculosum
Ohau Bay.  Coastal turf along the tops of the low cliffs.
At Ohau Bay the coastal turf is quite extensive along the top of a short eroding cliff, between a stagnant ponded creek—which has lost its way among the piles of driftwood—and goat-infested pasture inland.  There were plenty of introduced weeds among the turf, but Myosotis was mostly in the pristine bits.  Even the weeds are mostly small-flowered.
Pearlwort, Sagina apetala. That's an open capsule, not a flower

Sand spurrey, Spergularia rubra

Field madder, Sherardia arvensis

Friday, 4 November 2011

Nettles without stings

Every plant family name is typified by a genus, which means the name of the family is based on the name of a genus.  For instance, the name Brassicaceae, for the mustard family, is based on the name Brassica, which is the so-called type genus of the family.  But it would be a mistake to think the type genus is necessarily typical of the family in any other way. Viola, with its bilaterally symmetrical flowers and capsular fruits, is not a typical member of Violaceae, nor is wind-pollinated Plantago typical of Plantaginaceae.
The same applies to the nettle family, Urticaceae.  Most people have been stung by nettles, and I used to think, wrongly, that this is a family of stinging plants.  Heywood et al. (2007, but see Hadiah et al. 2008 for an update) refer to five tribes in the family and mention stinging hairs for only one, the Urticeae.  Interestingly, all five tribes are represented in New Zealand, suggesting the members of this family may be easily dispersed.
Tribe Urticeae includes the widespread temperate genus Urtica, which has five native and four naturalized or casual species in New Zealand.  These nettles all have stinging hairs, but U. australis on the subantarctic islands has very few of them. 
Urtica australis on Enderby Island, Auckland Islands.
Nettles often grow in nitrate-rich environments and they can accumulate rich nutrient reserves in their leaves.  This makes them a target for herbivores and the stings are an effective protection from some grazers.  Nevertheless nettle soup is a traditional dish in Europe.  Also nettles are readily eaten by caterpillars and thus they provide environmental support for butterflies.  I wonder if U. australis has few stinging hairs because it has few natural predators in its subantarctic home.
Urtica australis, flowers and a few hairs
New Zealand has one of the most spectacular nettles, Urtica ferox (the name means fierce) or ongaonga.  Ongaonga stings can be fatal, especially to horses and dogs, but humans have also been affected.  One botanist colleague has had a lucky escape, only just managing to stumble out of the bush in time.  Friends called an ambulance when they found him numb, partly paralysed, and disoriented.
Ongaonga, Urtica ferox.
The stiff stinging hairs are like little (not so little in ongaonga) hypodermic needles that inject the toxins under the skin.  The brittle tip of the hair breaks off on contact, and as the hair is pushed into the sac of toxins at its base the toxins are forced up its hollow shaft.  These toxins include formic acid, serotonin, and histamine according to Wikipedia, while some species contain oxalic acid or tartaric acid.  Connor and Fountain (2009) mention a toxin called triffidin that may also be involved.
With such active chemicals, it's no surprise that Urtica is widely used in herbal medicine and homeopathy.  Homeopaths believe that a substance that causes a symptom in a healthy person can be used to treat that same symptom in a sick patient. They also believe the more dilute a solution is, the more powerful it is as a treatment, even when so dilute that none of the original substance remains. They combine those two principles and believe highly diluted nettle extract is a remedy for skin rashes.
Nettles in the tropical genus Dendrocnide grow as small trees with very dangerous stings, and another genus Laportea is also notorious.
Parietaria judaica
The rest of the family is not so scary.  Parietaria judaica (pellitory, Tribe Parietarieae) is a common weed around Wellington city and many other parts of the country.  There is a native species, P. debilis.  Pellitory doesn’t have stinging hairs, but it is implicated in asthma and skin irritations.
Elatostema rugosum
Elatostema rugosum (parataniwha, Tribe Elatostemeae) is a large herb from the north of New Zealand, where it grows on stream sides and wet cliffs.  There’s also a good patch of it in the Wellington Botanic Gardens, just downstream from the duckpond.  No stinging hairs here either, so it’s an attractive plant for the garden.
Pouzolzia australis (Tribe Boehmerieae) is a small tree found on the Kermadec Islands as well as Norfolk and Lord Howe Islands.
Finally, Australina pusilla (Tribe Forsskaoleae) is a little creeping herb that’s said to be common in coastal and lowland forests.  I think I must often have overlooked it, so now I intend to keep an eye out for it.
So all these New Zealand Urticaceae are stingless nettles except for Urtica.  They shouldn't be considered to have evolved from ancestral plants that had stings, since stings seem to have evolved only in Tribe Urticeae.  Stinglessness doesn’t mean they’re entirely benign though.  The flowers in this family are small and wind pollinated, and the copious pollen production associated with wind pollination makes them a minor cause of hayfever.
Connor HE, Fountain J 2009.  Plants that poison—a New Zealand guide. Manaaki Whenua Press.
Hadiah JT, Conn BJ, Quinn CJ 2008. Infra-familial phylogeny of Urticaceae, using chloroplast sequence data. Australian Systematic Botany 21: 375–385.
Heywood VH, Brummitt RK, Culham A, Seberg O 2007.  Flowering plant families of the world. Firefly.

Sunday, 30 October 2011

Why are kawakawa falling over?

In Birdwood Reserve, near where I live, there’s been an epidemic of some sort affecting kawakawa, Piper excelsum.  Large plants lose their leaves and the roots seem to die off, because the whole plant falls over, as if wind-thrown.  There are still plenty of small plants alive, so it's not wiping them all out:

Kawakawa is very susceptible to spray damage, and certainly some of these dead plants are alongside tracks where weeds have been sprayed lately.  I’ve found the slightest spray drift of glyphosate is enough to wither kawakawa leaves and slowly kill the plants.

But some of these plants were growing where I don’t think there would have been any spraying, so I’m wondering if a disease is involved.  Indeed one such dead plant is in my garden, where I certainly haven't sprayed, but where nevertheless quite a few plants (not just kawakawa, but also northern rata (Metrosideros robusta) and akeake (Dodonaea viscosa)) have suddenly died.  The weather has been normal, except for the snowfall in August. 
In cabbage trees (Cordyline) sudden decline is caused by a phytoplasma.  This is an extremely small bacterium that's spread by sap-sucking leaf hoppers.  So far it's been implicated in deaths of cabbage trees, strawberries, coprosmas, and Phormium (New Zealand flax) (Liefting et al., 2007).  I've no reason to suspect any particular cause in this case, but the cabbage tree disease does show how devastating these things can be.
I'd be interested to hear if anyone else has observed similar collapse of kawakawa anywhere.
Lia W. LIEFTING, Ross E. BEEVER, Mark T. ANDERSEN, Gerard R. G. CLOVER Phytoplasma diseases in New Zealand.  Bulletin of Insectology 60: 165-166 (2007).

White mignonette

Reseda alba, Karori, Wellington, New Zealand

Resedaceae is a small family in the glucosinolate-producing Order Brassicales.  Reseda alba, white mignonette, is a cottage garden flower grown for the sweet scent of the flowers, and it’s naturalized in New Zealand.  These ones were semi-wild on a crib wall in Karori, Wellingon.

Saturday, 15 October 2011

Wellington coast at Makara

We took a great little walk today from Makara towards Opau Bay, along a section of Wellington coast.  The walk itself is described here, but I want to write about some of the plants.
The coastal cliffs are formed along the Ohariu Fault, one of the three main fault lines that define, and threaten, Wellington.  The cliffs are about 180 m tall here, and not so steep that you can’t scramble down them in most places.  Still, they give spectacular views up the coast to Kapiti and Mana Islands and westward across Cook Strait to the South Island.
Looking north from the cliff top.  Mana Island with Kapiti Island behind; Pukerua Bay headland (distant right) and Pipinui Point (closer, right)
East of the cliffs, it’s sheep farming country, but now also a wind farm.  The huge turbines were spinning slowly in today’s gentle breeze.
Down on the coast, it's pretty weedy, but a few native plants persist here.  Tetragonia is an edible, scrambling, slightly fleshy, plant in the ice-plant family Aizoaceae; this one is probably T. trigyna.
Tetragonia trigyna
A relative in the same family was also common on the coast: Disphyma australe.
Disphyma australe
At the high point of the track, there are more turbines, and on the cliff top two old gun emplacements from World War II.  Here the track descends again towards Opau Bay.
Looking south to Opau Bay
In the gully here a few trees of Pennantia corymbosa form the beginnings of a low forest among the mostly native scrub of tauhinu and coprosma.
Pennantia corymbosa
A few plants of Clematis forsteri were in flower among the scrub.  Sabrina said they smelled like feijoa fruit and she could smell them from a few metres away, whereas I could detect no scent even close up.  Callum said feijoa too, independently.  All the ones we saw were male.
Clematis forsteri
The flowers are pale yellow, and hairy on the backs of the sepals:
Clematis forsteri male flower
One patch was heavily infested with a rust fungus that distorted the growth of stems and leaves.  The little pink dots on the right hand piece are pustules where spores are released.
Clematis forsteri, infected by rust fungus (right) and not infected (left).

Some quite spectacular weeds grow in places along the coast.  Artemisia arborescens is a common hedge plant in coastal areas and has probably spread here from the nearby settlement.
Artemisia arborescens.

Aloe saponaria was growing beside one of the gun emplacements.  I wonder if it was originally planted there by the gun crews.
Aloe saponaria

Although we had an almost still day, there's no doubt this is a windy coast.  First of course, the decision to put a wind farm here reflects that, but also many of the plants are wind-shorn.  This Melicytus alpinus was so stunted that it was almost a solid outer shell of wood, with a few fleshy leaves attached.

Melicytus alpinus.

They say you can't beat Wellington on a good day.  I think the statement is deliberately ambiguous; it could refer to the rugby team, or to the weather.  Whatever, today was a good day.