Lobelia anceps – Angled Lobelia

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Typical plants growing in a non-calcareous sandy/peat soil

Plants growing in deep calcareous sand near creek outlet to the sea

Plants from a hollow and seepage zone in deep calcareous sand

Lobelia anceps – Angled Lobelia

In Western Australia due to the Classification System now adopted, Lobelia anceps is regarded as belonging to the Campanulaceae family, but may be placed into Lobeliaceae elsewhere. The species name has also been known as Lobelia alata, but has now been universally changed to Lobelia anceps. This species is very widespread and in Australia occurs from Geraldton (north of Perth) around the south coast (including, SA, Victoria, Tasmania and NSW) to north of Brisbane in Queensland, where commonly found in near coastal, cool moist soils. It is also found in New Zealand, South America and South Africa.

Lobelia anceps is a low sparsely branched perennial that will ramble near the ground or lean against taller vegetation to a height of around a metre (3’). It will grow in sun or shade, but requires a moist soil in exposed situations, so is usually encountered around seepage areas, swamps, lakes, streams, etc. It mainly flowers in the warmer months (September to May), but blossom can be found anytime.

Most Lobelia spp. are very sensitive to soil type, particularly the pH by either growing in acid or alkaline conditions. Locally, Lobelia anceps grows in both soils, but when in calcareous soil has different features from the norm and is probably evolving into a different species, but to what extent it has progressed down this path and if it should be classified differently, requires further study.

The above photographs have been divided into three groups, with the top four taken from plants growing around a non-calcareous sandy/peat soil and are reasonable typical of this species.

The centre four photos are from plants that were growing in an exposed moist situation, in deep calcareous sand near a creek outlet to the sea.

The bottom four photos are from plants growing around a hollow and seepage zone in deep calcareous sand, also close to the sea, but a more sheltered position.

The three colonies above are within 14 km (8.5 miles) of each other, to the west, and south of Mt. Merivale (20 km east of Esperance).

Lobelia sp. aff. gibbosa - Campanulaceae

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Lobelia sp. aff. gibbosa - Campanulaceae

This Lobelia is an undescribed annual species with affinity to Lobelia gibbosa and is currently lumped with it, but they have no ability to reproduce, despite in this instance growing within a kilometre of each other, simply because they flower at different times of the year. This species blooms in November and December, but locally L. gibbosa flowers from January to April.

Apart from the flowering time discrepancies, they differ considerably in appearance, with Lobelia sp. aff. gibbosa having smaller flowers that are purple (not blue) and a slender (not stout) stem, which is also purple (not a pale straw brown). Habitat is also very different with Lobelia sp. aff. gibbosa being only found in a low-lying area after fire, on the outer edge of a winter/wet depression, plus in shallow sand/clay loam over granite in association with Borya sp., Lobelia gibbosa does not occur in either of these habitats.

Lobelia sp. aff. gibbosa is currently only known from 4 colonies all near coastal to the east of Esperance and within a few kilometres (miles) of each other; three very small ones are on a couple of large rocky outcrops, each of less than five plants (2 colonies noted after fire). The forth and largest colony was in a moist sub-surface (not wet), sand/peat soil in a low-lying environment. Here there were around 30 plants in an area approximately 20 x 10 metres (66’ x 33’), with sedge and spaced Melaleuca sp. to 1.5 metres (5’) in height. This colony was first noted after fire (2005) and has been reducing in number ever since as taller species dominate.

An interesting observation concerns the small granite colonies of Lobelia sp. aff. gibbosa, which were found growing next to the equally rare coastal colonies of Lobelia cleistogamoides that were not seen elsewhere. This strange relationship may possibly relate to a symbiotic association of these species with soil microbes. It may also mean that like Lobelia cleistogamoides, Lobelia sp. aff. gibbosa is more common somewhere inland.

Locally, Lobelia sp. aff. gibbosa and Lobelia archeri are highly susceptible to a fungal disease (shown above) that is usually fatal. This disease strikes during high humidity after rainfall during November/December and is only curtailed by a bout of hot dry weather that kills it. Around Esperance, rain is unusual or of short duration at this time of year, so most plants escape this fate, although with climate change they could become early casualties.

Lobelia heterophylla subsp. heterophylla - Wing-seeded Lobelia

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Lobelia heterophylla subsp. heterophylla - Wing-seeded Lobelia

In Western Australia with the adoption of a different classification system, the genus Lobelia has been placed into the Campanulaceae family, although it may still be listed under Lobeliaceae by other authorities. Lobelia heterophylla and other species have recently been reviewed using DNA analysis, with this species being now separated into three subspecies. However it does not affect areas roughly south of Carnarvon, as only subsp. heterophylla is located here, with the others in Central Australia and the Pilbara.

Lobelia heterophylla subsp. heterophylla is an annual and a very widespread plant, found growing in a number of habitats, from coastal dunes to inland desert regions including granite outcrops. In the Esperance region there are two distinct varieties whose DNA has been investigated and although there are notable differences, they have not been considered sufficient to warrant subspecies status. However I shall separate them here to point out some of the differences.

Basically, the two varieties can be separated by habitat preference, with one occurring in smallish colonies (100 or less plants) and favouring low-lying areas in non-calcareous soils, although sometimes occurring directly over limestone, which would retain moisture for longer periods than purely deep sand. So I would suggest there are two main factors here, non-calcareous soils and a higher moisture requirement despite being found well inland. The flowers of this variety vary from sky blue to purple, but always have a yellow throat. It often branches into multi-stems that carry far more foliage than the other variety. Although if a dry year or germinated away from a sufficient moisture supply, will be stunted, single stemmed and with limited foliage.

The other variety is very habitat specific and only occurs in deep calcareous sandy soils, on stabilised, near coastal tertiary dunes. Here they can occur in their thousands and spread over large areas after fire, but most will disappear after a only few years. They do not occur in neighbouring deep acid (non-calcareous) soils or other habitats. They mostly have a single stem, but grow to around ½ metre (20”) in height and only after high rainfall will much foliage grow near the plant’s base; mostly they have small slender leaves that quickly shrivel. The flowers are sky-blue and always have a white throat, although a few all white flowering plants have been seen. The only overlap between these varieties, is on the different pH soil boundary where the non-calcareous variety is occasionally found growing in hollows in shallow soil mixtures over limestone.

Flowering is recorded from October to December, but locally both forms are seldom seen before November and rarely flower into the New Year, so November and December would be typical for this species in the Esperance region. The common name of Wing-seeded Lobelia refers to the wing on each corner of the triangular shaped seed.

Lobelia archeri – Campanulaceae

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Lobelia archeri – Campanulaceae

Lobelia archeri is a recently named annual species and has amongst the smallest of Lobelia flowers. It is only known from private property and neighbouring public land south of Mt. Merivale (20 km or 12.5 miles east of Esperance). It grows on the upper slopes of tall non-calcareous sand hills, although odd plants can be found lower down after fire.

Growing to around 40 cm (16”) in height, it usually has a thin unbranched stem with several small pale blue flowers near the summit. Being such a small plant, Lobelia archeri requires open spaces to survive as it can be quickly displaced by other vegetation, therefore it benefits from the after-effects of fire that temporally reduces dense or taller vegetation. This provides space for small plants to flower and set seed, some of which is added to the soil seed-bank for future use.

The need for open spaces is I suspect the reason why this species favours the upper slopes of tall sandy hillsides, as these dry windswept positions do not encourage colonisation by many plants, particularly large ones, thereby providing an environment with gaps between vegetation for longer periods. Lobelia archeri will spread quite quickly with a regular fire routine and is probably a species that has been disadvantaged by bushfire reduction under European Fire Management (see http://natureitems.blogspot.com/2006/12/fire-management-european-verses.html for further details).

Another reason why this species prefers an open windswept environment is a fungal disease that attacks the vascular system causing collapse and death. This and other Lobelia species are particularly susceptible to this infection after rainfall in sheltered places during the latter part of the year. Lobelia archeri flowers from late November to early January.

Lobelia rarifolia – Campanulaceae

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Lobelia rarifolia – Campanulaceae

Lobelia rarifolia is an annual herb and quite common in the Esperance region, although mostly near coastal and favouring winter-wet depressions and low-lying areas. Locally it can be encountered after fire in sandy/peat loams, or shallow sand over gravel, where they usually form scattered reasonably compact colonies of 10-100 plants, but as taller surrounding vegetation matures; colonies disappear until after the next fire.

Ranging from Cape Arid (east of Esperance) to Kalgoorlie in the north, then west to Geraldton, Lobelia rarifolia is quite widespread, but represented by limited collections, possibly because you need to be in the right place to catch them in flower. Locally this is from late October to December, although they may bloom earlier further north.

Unlike most other Lobelia spp. that have multiple flowers along the stem, Lobelia rarifolia has only a single flower at the summit, although there may be two or three minor ones branching from the upper portion of the main stem, which also produce a single flower. The stems often have scattered small linear leaves, which as its name suggest are not overly numerous, but as the 2 cm (3/4”) long flowers are an attractive deep blue, they readily draw the observers eye. Overall, plants seldom exceed 20 cm (8”) in height, but can grow taller if pressed by surrounding vegetation.

Lobelia cleistogamoides – Campanulaceae

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Lobelia cleistogamoides – Campanulaceae

Until the year 2007, Lobelia cleistogamoides was known only from a few herbarium specimens and called Lobelia sp. ‘small flowers.’ It is closely related to Lobelia heterophylla, but has a much smaller flower. Generally it is a slender upright and unbranched annual herb to ½ metre (18”), but when young, it will branch (mostly at the base) if damaged. New growth has narrow stem leaves to 2 cm (3/4) in length, but these shrivel during hot weather to leave only the flowers.

Although Lobelia cleistogamoides can occur near the coast, it is very much an inland species, favouring a coarse sand or gravelly loam often over granite. As such this species can be found in alluvial deposits around granite outcrops, where although localised is often very common. Like other Lobelia spp. they require open conditions to thrive, so do very well after bushfire, although these dry inland environments are rarely short of open areas, so some plants can usually be seen.

Around local near coastal granite outcrops I have encountered less than 20 plants in a handful of very small colonies, usually after fire or in shallow soil amongst a Borya sp. The reason why this species may be less common here, is possibly due to a fatal fungal disease (shown in a later post), which the higher coastal rainfall and humidity encourages.

Herbarium records have Lobelia cleistogamoides ranging from Mt. Ragged to east of Geraldton and a couple of collections from the Eyre Peninsula in SA. The mainly blue flowers (occasionally lighter or even white) have a yellow centre and are less than one centimetre (¼”) in length. They bloom between October and December, with odd flowers surviving into the New Year.

Lobelia gibbosa - Tall Lobelia

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Lobelia gibbosa - Tall Lobelia

The genus Lobelia was until recently part of the Lobeliaceae family, but in Western Australia with its adoption of a different classification system, it is now placed in Campanulaceae. Lobelia gibbosa is one of its most widespread plants, being found from Geraldton to Mt. Ragged, then across the Nullarbor to SA, Tas, Vic, NSW, Qld and the NT, so virtually Australia wide. Naturally, ranging over such a large area, variances do occur, so I shall restrict myself purely to the Esperance region.

Locally Lobelia gibbosa can be found in deep non-calcareous sand (Banksia heath), around granite outcrops (particularly coastal), plus shallow sand overlying gravel, where they can be quite common in small scattered groups. During mid-summer, these habitats are mostly very dry, but this is the only time these annual plants flower. It achieves this by germinating around October when there is usually sufficient moisture and occasional rainfall, and if unusually dry then, there will be fewer plants later on. As it develops, it takes up moisture and stores it in its bloated stem, but when it starts to flower (often-late January) the roots are almost non-functional and act mainly to anchor the plant in the soil. The plant if uprooted and provided with sunlight, will continue to grow and bloom.

The flowers are between 2-3 cm (1”) in length and due to summer temperatures that can exceed 40 degrees Centigrade (over 100 degrees F), are often the only herbaceous plants flowering. They prefer an open sunny position, so receive whatever the weather can throw at them, yet these delicate looking plants thrive in these conditions. If the habitat becomes too overgrown, Lobelia gibbosa will eventually die out or with odd ones remaining, so slashed walking tracks can be very good places to find them.

The flowers come in various shades of blue and very occasionally almost white; they mostly have a central white stripe along the three large petals. Several flowers are produced at the summit of the usually unbranched stem to 40 cm (16”) in length, which open progressively from the bottom up, so commonly bloom for a couple of months. Locally they flower from January to April, although February and March are their main period. This flowering time is important, as I shall refer to it in later Lobelia posts.