Western Australia is home to the greatest number of carnivorous plant species anywhere in the world. The south-west of the state is known for its incredibly varied geography, leading to intense floral biodiversity especially in Drosera. This region is the dream travel destination for many carnivorous plant enthusiasts.
At the end of winter in 2019, Boaz Ng, medical researcher and carnivorous plant enthusiast, turned this dream into a reality when he embarked on an expedition to document the carnivorous plants of Western Australia. He started his journey in Perth, performing a broad circuit of the south west of the state, before heading north for a few days. His search for these plants led him through dense forests, thick swamps, dramatic mountains and ancient plains. Over two and a half weeks and almost 3,500 km on the road, he was able to observe over 50 species of carnivorous plants in their natural habitat.
As soon as I landed in Perth I was ready to begin exploring. This two-and-a-half-week expedition to document carnivorous plants in the wild was months in the making and I had spent hours compiling sites, species lists and scouring Google maps for locations to investigate. I met up with my good friend Peter at the airport and hurriedly picked up the rental car. It wasn’t long before we were speeding southbound on the highway towards the coastal city of Bunbury, where we were to spend the night. There was no time to waste. Drosera were waiting …
South-west Western Australia is home to over 100 tuberous and pygmy species of Drosera, most of which are found nowhere else in the world. These plants have adapted for the harsh seasonal dichotomy of the region, actively growing in the cooler winter months before going dormant in the bone-dry summers. Many are tuberous species, which retreat into an underground corm to survive the annual desiccation. Of these, there are three main morphological groups: The first is the tuberous rosetted sundews, which develop flat ground-hugging leaves from a central growing point. The second is the erect and scrambling species that send up a thin stem on which carnivorous leaves emerge at regular intervals. The last is the fan-leaved sundews, with rounded leaves along fleshy stems that arise from a central rosette. There are also the pygmy Drosera, diminutive rosetted plants that form a tight reflective bud in the summer to bear out the heat.
After an hour or so of driving, we tried our luck and stopped at a disturbed rest area by the highway. As I poked around the weeds and grasses, my eyes were drawn to a sparkle and I was ecstatic to discover that it was from the dewy leaves of Drosera stolonifera! I was particularly impressed by the imposing form of this fan-leaved species – the cuneate laminae that emerged from the thick sprawling stems reminded me of the tentacles of an octopus. I had discovered my first sundew and I had only been on the ground for a few hours. Keen to find more, we forged onwards towards Bunbury.
The Bunbury area is situated on the flat Swan Coastal Plain and is dissected by swamp, forest and seasonal watercourses. This variable environment gives rise to many different niches, which in turn supports a great diversity of species. Our next stop, a forested reserve on the outskirts of the city, gave us a better glimpse into the natural state of the area. Immediately we saw the scrambling stems of D. pallida tangled amongst the bushes. Growing over 2 meters in length, the species uses its leaves to latch onto surrounding vegetation and elevate itself above the ground. I also saw massive colonies of D. erythrorhiza in the sandy soil. It is known that this sundew reproduces prolifically through lateral stolons that produce new tubers and is often encountered as dense and isolated carpets as a result of asexual reproduction. In some areas, the plants grew so prolifically that they covered entire clearings with their round, green rosettes. By now the daylight was rapidly diminishing so we hurried on to check into our accommodation in Bunbury and rest after a long day travelling from the other side of the country.
We awoke early the following morning before sunrise to get some exploring done in a nearby nature reserve. The trail we followed took us through a variety of habitats, with each niche presenting different species of sundews. Beginning in a woodland area similar to the one we explored the day before, the first rays of the sun illuminated nice patches of the familiar D. stolonifera, pallida and erythrorhiza. As we continued onwards, we were taken to a low-lying swampy area where I noticed D. rosulata, a rosetted species with a sunken midrib colonising the peat. The scrambling red stems of D. drummondii could be seen in exposed sandy areas and I was able to spot a single stem of D. porrecta, a fan-leaved species with whorls of leaves emerging from the bushes. On top of this, I sighted two species of pygmy sundew, most of which are unfortunately almost impossible to identify without flowers. I had already spotted so many species in such a short amount of time and my day had only just begun.