Carnivorous Plants Around Harvey, Western Australia

 

Robert Gibson

 

                In September, 1995, I visited Phill Mann and spent an afternoon looking for sundews in the hills east of Harvey. Our brief expedition proved to be very successful as we found 11 species of Drosera, many in the peak of their growth cycle and growing in great abundance. The following is an account of the species seen and their growing conditions.

 

Drosera erythrorhiza ssp ? collina

                Large green to orange robust rosettes of a taxa of Drosera erythrorhiza very similar to ssp collina were seen in a few locations in the Jarrah forest. The first site was a shaded, poorly defined creek bed where the scattered rosettes, to 7cm diameter, grew in peaty, moist soil. The plants grew with D. gigantea and none had flowered.

 

                This taxon grew in greater abundance in an area of lower density trees on an area with orange, rounded gravel piesolite-covered soil. The area was well drained, and the irregular, very coarse soil was uncomfortable to lie on. Here, however, this attractive variant grew in abundance. The fully bedewed rosettes to 10 cm diameter were variably orange pigmented and often grew in small clusters. This taxon, with 4 to 6 ovate leaves, and with rare asexual reproduction appears closest to ssp. collina. More work, however, is warranted on this, and other taxa in the D. erythrorhiza complex.

 

Drosera gigantea

                Drosera gigantea was seen in two sites, the first was in the bed of poorly formed creek in open Jarrah forest, on soil derived from laterite. The soil was moist, with some accumulation of organic matter on the surface. The plants grew amongst clumps of sedges, in the shadow of a range of shrubs of the Myrtaceae family. Despite the time of year the D. gigantea plants here were still forming the initial branches and were months away from flowering. Many still looked like stalks of asparagus, and they growing the company of variably green to orange rosettes, to 10 cm diameter, of D. erythrorhiza ssp ? collina.

 

                The second site was on a sodden, north facing granite slope which supported few woody plants. An abundance of annual and summer-dormant, often tuberous, herbs grew abundantly in the moss, and Borya-covered thin soil. Here D. gigantea grew in abundance and, in contrast to the previous site, most plants were in flower. The plants were generally golden green, although some plants had red stems, and produced a golden green glow when backlit by light of the setting sun. The plants grew to 70cm tall, and were most abundant towards the top of the granite outcrop, perhaps due to the slightly deeper soil where the slope was not too great. In places the plants grew in such abundance that it was difficult not to damage plants when moving around the site. Despite the abundance of flowers produced by the plants here in most general this species rarely sets seed in the wild. Perhaps the abundance of Drosera gigantea plants at this site reflects prolific asexual reproduction from the production of daughter tubers underground and by the formation of tuber s from the leaves of fallen plants. Perhaps this species needs a fire the summer before to trigger a greater amount of seedset? This sundew grew with D. stolonifera ssp stolonifera, D. macrantha ssp macrantha and D. glanduligera at this amazing site.    

               

Drosera glanduligera

                Drosera glanduligera were seen in the area. The plants had golden green rosettes to 3cm diameter, many of which were just starting to produce scapes. Plants were seen in moist sandy peat soil of a swampy creek bed which slowly cuts its way through the Jarrah forest. Plants were also seen growing in sodden moss, amongst boulders, on a north facing granite outcrop over which fresh water was continually seeping. This annual grew in the company of Drosera pallida, D. gigantea, D.stolonifera ssp stolonifera and D. macrantha ssp. macrantha.

 

Drosera macrantha ssp macrantha

                The first species of sundew found on the trip were climbing plants of Drosera macrantha ssp macrantha which grew in well drained laterite-derived soil on roadside embankments. Many plants grew immediately beside the road. Many plants were in flower, and showed some of the range in petal size and colour which is found in this variable taxa.

 

                Abundant plants were also seen growing in moss, and thin soil on a moist granite outcrop in the company of D. gigantea, D. glanduligera and D. stolonifera ssp stolonifera.

 

Drosera marchantii ssp marchantii

                Numerous plants of the erect growing Drosera marchantii ssp marchantii grew in well-drained laterite-derived soil on roadside hills, and in clearing in the jarrah forest. This attractive species has a swollen base, with many short, bract-like leaves at the base of its golden green stem.  Many plants were in flower at the time of our visit and the sweetly scented, rich pink petalled flowers, to 2cm diameter were a sight to behold. Many plants grew with D. macrantha ssp macrantha.

 

Drosera neesii ssp neesii

                A few erect plants of golden green Drosera neesii ssp neesii were found in damp peaty sandy soil in the swampy creek. The scattered plants often grew in, or adjacent to channels. They were up to 20 cm tall and were at least a month away from flowering, and could have either pink or yellow petals. This species has a preference to growing in damp peaty soil which rarely fully dries out during the summer, and was seen to grow near D. glanduligera and D. pallida.

 

Drosera pallida

                A few slender climbing plants of Drosera pallida scrambled over low woody shrubs on the drier parts of the swamp in the Jarrah forest. This species has a smooth, slender dark green stem with rounded leaves in threes with bright red long stalked retentive glands. In leaf and flower size it is a variable species, which is widespread in south west Western Australia. In this area it grew near D. neesii ssp neesii and D. glanduligera. However, from what I’ve seen elsewhere in the state this species is probably widespread in the Jarrah forest in the area but was not seen.

 

Drosera pulchella

                 A few non-flowering rosettes of Drosera pulchella grew beside and in the creek bed of a small ephemeral creek. The rosettes were variably hidden by grasses and sedges, and grew in soil which was likely to remain moist well into the summer. The plants grew downslope of an area cleared for Eucalyptus plantations, which otherwise would have supported a range of other sundew species.

 

Drosera scorpiodes

                Attractive, robust, often long stemmed plants of Drosera scorpiodes grew in an area of open Jarrah forest, on a coarse, well drained surface layer of which is composed of rounded, orange, gravel-sized piesolites. The rosettes were fully bedewed, up to 4cm diameter, on often leaning stems to 10cm long, and had the first scapes of the season just emerging from the centre of the rosette. This species grew with D. erythrorhiza ssp ? collina, and was very attractive when backlit by sunlight.

 

                This population of D. scorpiodes is unusual in two respects. Either it is a very isolated population or it shows that this species is more widespread than has been previously reported. In addition the petal colour of these plants is an attractive dark pink. It is a very attractive form of the species.

 

Drosera stolonifera ssp compacta

                A few very red plants of Drosera stolonifera ssp compacta grew on the open floor of Jarrah forest and were readily seen from a moving car. The plants grew upright, with up to 4 stems, and, rarely, the remains of a scape. Unlike Drosera stolonifera ssp stolonifera this subspecies grew in scattered colonies, was self-supporting and the above ground growth was immediately above the tuber. The plants grew in moist, but well drained, sandy soil, probably on laterite. The area where the plants had been growing had been burnt the previous summer and the forest floor was still very open. A thin layer of bright green moss grew on the charcoal rich layer on the soil surface. No other sundews were found growing with this species. 

 

Drosera stolonifera ssp stolonifera

                Stunning red, multi-branched plants of Drosera stolonifera ssp stolonifera grew in abundance in damp, shallow soil on a prominent granite outcrop over which water was continually flowing. The stunning red plants stood out from the accompanying grasses and summer dormant herbs and had between 3 to 6 fully bedewed branches, to 15 cm long. Many of the plants had flowered and most flowers had set seed, ripe seed was being shed from the dieing scapes at the time of our visit. This species grew with D. gigantea, D. glanduligera and D. macrantha ssp macrantha on the more exposed part of the granite outcrop, but this species also grew upslope on the same granite outcrop in the Jarrah forest. This very attractive species buries its tuber deeply into crevices in the granite. The above ground growth initially grows horizontally before the leaf rosette, with basal leaves branching stems, and, if large enough, scape is produced.

 

                Only a few plants of the winter-growing annual herbs assist in holding the plant upright. This species looked stunning when the large colonies of it glowed red by the light of the setting sun behind them. 

 

                The nine species of tuberous Drosera were found in all three subgenera and it was interesting to see which plants grew together and the environments in which they grew. The two species of pygmy Drosera seem grew in very different environments.

 

                It was excellent to see such a range of native sundews growing in the wild on a short trip. It provides food for through of what could be found in the area by spending more time and travelling further in the region.

 

Acknowledgments:

                I wish to thank Phill Mann  for his company and showing me a few plants in his “backyard”.