Drosera salina - Saltlake Sundew

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Drosera salina - Saltlake Sundew

This species is known only from a handful of locations, but due to its small size and condensed colonies can occur in their thousands, so although not a rare plant, it does have a rare and unusual habitat. It grows around saltlakes (which are very common), but only those with a thin layer (less than 3/8” or 1 cm) of fine wind-blown white quartz sand overlying a heavier clay/sand mixture, which when combined is very unusual. This situation happens where rainwater run-off gently flows from small surrounding catchments; in this instance, soil from these catchments was a free draining sand/clay and had (if any) a low saline/alkaline content, although the saltlake water was very salty.

The plants grew from a tuber roughly 3 cm (little over an inch) below the clay/sand substrate and as it reached the overlying quartz sand formed a rosette of small green leaves, but these did not extend to the surface so were not visible from above. The red stemmed Drosera salina grew vertically to a height of around 3 cm, where they were so numerous that collectively they formed a red tide, which could be seen from some distance at the northern end of the lake.

The saltlake where these droseras were found is quite small, being of similar size to an athletics stadium; these lakes are normally dry, but rain had recently fallen and it had filled to a good level. When I was there in late June, the plants were only in bud and when I returned 2 months later, they had finished flowering, so unfortunately my timing was just out on both occasions, therefore currently there are no flower photos. The flowers are recorded from July to September, but would be dependent on local weather conditions; the plants die back as temperatures rise, but reappear the following winter/spring.

Drosera salina has a Priority Two conservation code rating, which means it is known from only a few locations (usually less than 5), most of which are not currently under threat, but are in urgent need of further survey. The lakes where this species occur, range in a band from Peak Charles to the Lake Grace region. The colony I encountered was a new location, but fitted within the known distribution pattern.

Drosera is part of the Droseraceae family.

UPDATE Sept 2016
Three flower photos added.

Drosera zonaria - Painted Sundew

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Drosera zonaria - Painted Sundew

Although an exceptionally common plant, few people have ever seen it flowering in the bush. I have done so on two occasions and then only when associated with a bushfire. Even when in flower they can be easily overlooked, as the rosettes only appear after the flowers have formed, so the (1 cm or 3/8” dia) white flowers that grow close to the ground and against their usual white sandy habitat can be difficult to spot.

The distribution of Drosera zonaria occurs in a band from Cape Arid to Ravensthorpe, then NW to the Perth region thereby excluding the SW corner of the State. Within its range, it would be difficult to find anyone interested in botany, who has not seen their compact colonies, as their green and red edged leaves form rosettes, commonly growing to over 5 cm (2”) diameter that are not easily missed in their heath or open woodland environments.

Drosera zonaria has little need to produce flowers, as it mainly reproduces vegetatively, which it does by budding off to form clones of itself from its subterranean stem and above the orange spherical tuber a few centimetres (2”- 3”) below the surface. However flowers are required for gene diversity and to establish new colonies, which from my experience they produce after bushfires, when the ground would be cleared of other vegetation and fertilised with their ashes. Seed would probably be spread after passing through the gut of ground feeding animals and birds.

From the flowering plants observed, one colony was where the fire had passed over and the other in an unburnt open space nearby, so the chemicals in smoke may have been sufficient to stimulate floral development. In both cases flowering (recorded from April to June) was in the winter period following a summer fire. The leaves appear during the latter stages of flowering, but will die-off at the approach of warm weather, generally by late spring or early summer.

Drosera is part of the Droseraceae (Sundew) family.

Drosera nitidula - Shining Sundew

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Drosera nitidula  -  Shining Sundew

The local habitat of Drosera nitidula is quite interesting and illustrates the subtle difference between its requirement and that a more common species Drosera pulchella. They are both found in swampy environments that may be inundated for short periods, but locally they do not grow together. The difference is D. pulchella is common in swamps or strong seepage areas, whereas D. nitidula is found on the edge, or low rises along flood plains in a silt/sand soil.

The difference between a swamp and a flood zone is the movement of water. Swamp water moves slowly or not at all, largely reducing in size by evaporation. Flood plains on the other hand, the water slowly moves through the area due to gravity, often ending up in a swamp. This means in the dominant winter rainfall of Esperance, the habitat of Drosera nitidula can be sodden after heavy rain, but as the habitat slowly dries at the approach of summer, the ground becomes completely dry and then the leaves shrivel and die.

Drosera nitidula is a perennial, therefore normally survives the hot dry summers to await the next wet period (including heavy summer storms) when new leaves will appear from between the long stipules of the stipular bud, which has protected the plant during its dormant phase. Drosera pulchella will often fully retain its leaves, as its habitat is more likely to remain moist throughout the dry summer period and possibly due to this compatible environment, the plant is more widespread.

The Shining Sundew although small (1.5 cm or 5/8” diameter) is well named, as the leaves glisten a bright orange/red. However it is even more identifiable by its large dark red orbicular stigmas, which besides a rare hybrid, is the only local Drosera to possess them. The hybrid is known as Drosera x legrandii that is only known from a small colony in the Cape Le Grand region (east of Esperance), it has 4-5 clavate (club shaped) blood red stigmas.

Drosera nitidula mainly occurs in the Perth to Albany region and around Esperance. It is recorded flowering from November to January

Drosera belongs to the Droseraceae (Sundew) family.

Drosera sargentii

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Drosera sargentii

This locally endemic, perennial pygmy Drosera is very common around Esperance in near coastal, non-calcareous, deep white sand, especially east towards Cape Arid. Apart from the soil type, it is highly adaptable, being found on low sandy rises around swamps to small sunny clearings on the tops of gentle sloping sand hills, commonly associated with Banksia speciosa.

On sandy rises above flooded swamps, it is not unusual to find three Drosera species growing together, with D. pulchella occupying the lowest zones closest to the water and D. australis growing just above in a moist soil, whilst D. sargentii are above them in a better drained location. On hilltops, this species is usually located in small level clearings, where rainfall will soak into the soil and not run-off.

Drosera sargentii is very easy to identify, as the stipules have long white whiskery hairs that are quite distinctive, which collectively also form a characteristic stipular bud. The number of flowers per stem apparently can number to 50, but locally they tend to be considerably fewer. The flowers are white with pink markings at their base and petals are noticeably rounded at their summit.

The rosettes are to 2 cm (3/4”) diameter and the flowering stems to around 5 cm (2”) in height, they usually flower during November and December and form open colonies that are mostly less than 10 square metres/yards in area. The habitat photo above had been burnt the year before, but the lightly slashed path (centre) and lack of fuel there had protected a Drosera colony.

Drosera is part of the Droseraceae (Sundew) Family

Drosera australis – Southern Sundew

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Drosera australis – Southern Sundew

This pygmy Drosera is currently known as Drosera occidentalis subsp. australis, but I prefer to go with Allen Lowrie (an Australian Drosera Authority) with his listing in his large and highly detailed 3 Volume work titled “Carnivorous Plants of Australia Magnum Opus.” In it he regards subspecies australis, as a distinct species and of which I concur can be very common along the south coast from Augusta to Israelite Bay (east of Esperance).

Locally it occurs in sandy soils, sometimes with a high humus content in light seepage areas, or the moist soil just above inundation zones, where species like D. pulchella commonly occur. Lowrie now places Drosera occidentalis, which is a very similar species along the west coast either side of Perth and spiking SE to the Gnowangerup region (north of Albany), so well outside the Esperance region.

In the Esperance district, Drosera australis usually has only one, occasionally two or three flowers, but apparently plants further west with better growing conditions can have several. The deep red leaf rosettes are mostly less than 2 cm and usually around ½” diameter, although they can congregate together to produce much larger clumps. The small flowers (to 5 mm or 3/16” diameter) are very shy bloomers and have 5 petals (the one shown above had lost a petal) and flower between October and January.

Drosera is part of the Droseraceae (Sundew) Family.

Drosera ramellosa - Branched Sundew

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Drosera ramellosa - Branched Sundew

This widespread Drosera (Geraldton to the edge of the Nullarbor) is a WA endemic and comes in two forms apparently dependent on geographical location, although both favour a similar habitat, this being granite outcrops or close by and under their influence. The species especially favours gently sloping ground in a coarse sand intermixed with a heavy loam over granite, limestone or clay, but also where light seepage moves slowly down over the substrates, thereby keeping the shallow growing medium moist.

Of the two forms mentioned above (at least locally) one occurs inland, whilst the other is coastal, the main difference being the amount of moisture and the period of time it is available to the plant. The coastal form commonly grows on gently sloping moss covered granite, where average rainfall is around 60 cm (24”) a year and reasonably reliable. These plants produce several tall (to 12 cm or 5” high) leafy erect stems from a basal rosette that progressively turn red; they also have one or more branched flower stems, each with 1-3 flowers.

The inland form has up to half the average coastal rainfall and is often unreliable; plants rarely form the leafy upright stems, but usually have only the basal rosette or combined rosettes that remain green. The flowering stem, although similarly branched as the coastal form is very short and largely hidden. On occasion during an unusually wet period, I have observed some plants with odd leafy stems, but these too remained green and were far less impressive than the coastal form.

Drosera ramellosa is a Tuberous Drosera with branched styles, but lacks the stipules of Pygmy Droseras. The flowers can be white or pink and are produced between June and September, however locally, the inland form tends to be the earliest and the coastal the latest.

The Drosera genus is part of the carnivorous plant Droseraceae family.

Drosera aff. pycnoblasta - Pearly Sundew

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Drosera aff. pycnoblasta - Pearly Sundew

Knowing the considerable interest in carnivorous plants, I have included this species in order to bring attention to a variation of D. pycnoblasta. It differs from this species in several respects and may be more widespread than is currently known. Specimens have been submitted to the WA Herbarium who are confident its closet match is D. pycnoblasta than to any other species. It is currently known as Drosera aff. pycnoblasta and will probably remain that way until additional information comes to light.

Currently only known from deep white or yellow sand to the south of Lake Tay (140 km or 90 miles NW of Esperance), where common and widespread. It most notably differs from D. pycnoblasta by having five (not three) styles, plus the petals lack any coloured markings, also plants produce considerably more flowers (numbering to 30 per scape). However the stipules are entire (without any pronounced projections or indentations), which are similar to D. pycnoblasta and an important identification feature.

Plants grow to around 5 cm (2”) in height, with a basal rosette of around 1 cm (3/8”) diameter and have tiny circular leaves. The previous year’s growth is persistent, eventually forming a 1 cm high pedicle supporting more recent growth. Interestingly, this pedicle is formed by tightly packed small windblown grains of sand that probably provide insulation, plus act as a moisture trap for the fibrous root system, which is surprisingly shallow.

All foliage dies (although still retained) during summer, when temperatures in this region can exceed 40 degrees C (over 100 degrees F) in the shade, and considerably more in the sun. Flowering has been noticed from September to early December, although October/November would be the main period.

My thanks to the WA Herbarium for their identification assistance.

The Drosera genus is the major part of the Droseraceae family.