Callitris canescens - Scrubby Cypress Pine

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Callitris canescens - Scrubby Cypress Pine

This conifer is not a common tree of the Esperance region, with the above seen growing on and around a 2 metre high gypsum mound on Lake Sharpe that is to the west of Peak Charles and 130 km (80 miles) NW of Esperance. Here there is only handful of plants in various stages of development and have obviously survived in this remote habitat for a considerable period of time, as the surrounding low open saltbush and samphire vegetation has been insufficient to carry flames from the outer wooded areas during bushfires.

Callitris canescens grows to around 6 metres (20’) and forms either a small tree with a single trunk or a tall shrub with multiple trunks. It is certainly a very tough plant growing in a totally exposed, hot, arid, windblown environment in dry alkaline gypsum soils. Rainfall here is generally less than 250 mm (10”) a year and temperatures in the shade are commonly over 40 degrees C (over 104 degrees F) during summer.

The Scrubby Cypress Pine can be easily confused with Callitris roei that is a more common conifer in the area. Visually the most distinguishing feature is the foliage; C. canescens has shorter leaves on the ultimate branchlets of between 2-4 mm (mostly around 2-3 mm or 1/8”) in length, and importantly the dorsal surface is rounded. Callitris roei on the other-hand has leaves almost twice that length and commonly 4-5 mm or ¼” in length; the dorsal leaf surface however, is strongly keeled as if a boat had been turned upside down.

Both C. canescens and C. roei have female cones with dorsal protuberance near the apex, but those of Callitris canescens are very small, lightly structured and easily damaged. C. roei are far more robust, the cones are also slightly larger (around 2 cm or ¾” diameter) and from the many I have seen, have a distinct silvery grey appearance.

The White Cypress Pine, Callitris columellaris has even smaller leaves than Callitris canescens and also with rounded dorsal surfaces, but the cones are much larger (commonly to 2.5 cm or 1” diameter) and often have a less even surface with slight bumps, ridges and hollows that become more pronounced as they dry.

Callitris canescens is endemic to Australia and is mainly found in WA (mostly inland) from Kellerberrin to the Kalgoorlie region and south to Ravensthorpe, plus on the Yorke and Eyre Peninsulas including southeastern parts of SA.

Callitris is part of the Cupressaceae (Cypress family).

Callitris columellaris - White Cypress Pine

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Callitris columellaris - White Cypress Pine

This Callitris is very widespread and generally found in the warmer regions of all mainland States, although around Esperance it is only recorded for the far NE and NW of the region where it favours gypsum soils around saltlakes, but elsewhere it may be encountered in a variety of habitats. Those photographed above are from the Lake Tay southern shoreline and what looks like white sand is actually gypsum crystals.

The gypsum forms on the dry open saltlake and is blown by strong summer winds to form low dunes around the shore; behind these dunes are Samphire flats, and behind those are much taller powdery gypsum dunes.

The status of Callitris columellaris is not recognised by all State Herbaria and is known to them as Callitris glaucophylla (including C. columellaris in WA), although they do recognise a species called Callitris columellaris, which is a taller near coastal tree restricted to NSW and Queensland. This difference of opinion will likely remain until these plants are reviewed at some future time. My thanks to the WA Herbarium for clarification of this matter.

In WA the White Cypress Pine grows to around 8 metres (26’), but in the Eastern States can reach 20 metres (65’) and are commercially harvested. The timber is highly valued as it is attractively marked, durable and resistant to termites.  Because of its hardiness, skeletons of trees that have died may be standing for many years before eventually falling over.

The cones of Callitris columellaris are smooth or finely wrinkled to 2.5 cm (1”) diameter and the tiny leaflets that are arranged in three’s around branchlets, are to 3 mm (1/8”) in length. On most plants the new foliage is glaucous (pale blue or whitish), to give the common name of White Cypress Pine.

The Callitris genus belongs to the Cupressaceae family.

Callitris pyramidalis - Swamp Cypress

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Callitris pyramidalis - Swamp Cypress

This Callitris was until very recently (2010) listed in the Actinostrobus genus, which has since been discontinued. It was initially separated from Callitris by having scales at the base of the mature female cones, plus the valves being of similar length, but after DNA study they were found to be very closely related and so were combined under the Callitris banner.

There were three Actinostrobus species, which were separated from each other by the shape of the mature cones, which with C. pyramidalis has a rounded top. This feature, plus the basal scales and the similar length valves will now distinguish it from other Callitris spp.

In the Esperance district Callitris pyramidalis is only known from the Cape Le Grand National Park, but is common in low-lying areas west of Ravensthorpe both inland and along the coast to Kalbarri (500 km or 310 miles NNW of Perth). Locally it grows in a sandy soil overlying granite, where rainwater run-off from a nearby granite outcrop would likely create sub-surface seepage.

Above are shown the juvenile male and female cones that occur on the same plant, plus mature female ones that will release their seed after a bushfire. Apparently this Callitris species burns readily and intensely, which has restricted its use in home gardens. Trees are generally bushy and unless damaged when young, will usually produce a single trunk that can grow to 5 metres in height, however if the young growing tip is damaged or eaten by a browsing animal, a multi-trunk shrub is often the result.

Callitris belongs to the Cupressaceae family.

Callitris roei - Roe's Cypress Pine

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Callitris roei - Roe's Cypress Pine

Australia is not normally considered when conifers are being discussed, as environmental conditions here are so unlike the cooler, moist habitats of the Northern Hemisphere. Yet we have a diverse selection of these plants ranging from Cycads to Pine Trees, which collectively are known as Gymnosperms. These shrubs and trees like flowering plants also produce seed, but whereas seed from flowers are contained within an ovary-like structure formed by the carpel, Gymnosperm seed are formed within a cone.

There are a number of Australian Gymnosperm family members, with Callitris belonging to Cupressaceae. In Western Australia there are 10 Callitris species, of which 5 can be encountered in a variety of habitats within the Esperance region and distributed from the coast to the inland mallee region. The main distinguishing features of these plants are the shape and arrangement of the foliage and female cones.

Callitris roei is found from the NE of Perth to Israelite Bay and around the coast to Albany, an area largely explored between 1829 and 1848 by John Septimus Roe, the first Surveyor-General of Western Australia, after which this conifer is named. Around Esperance this species mainly occurs on level ground within the mallee region, particularly where sandy loams overlie clay or gravel.

Roe's Cypress Pine can grow to 5 metres (16’) in height, but locally is mostly half that size. It seems to like warm weather coupled with a moist well-drained soil, which if found will stimulate a larger and bushier tree, but in the dry mallee, trees are often spindly and more stunted. The attractive foliage is commonly blue/green (glaucous) and the 2 cm (3/4”) diameter cones, bright silvery brown.

This species is distinguished from others by having a smooth cone, with a single dorsal point on each cone valve, plus three leaves that encircle the branchlets to produce a triangle in cross section with acute edges. The only similar looking conifer in the Esperance region is Callitris drummondii, which does not have any dorsal points (the cone valves being smooth all over), plus is more a bushy small tree or shrub, with greener foliage and darker coloured cones.

Above is a photo of the tiny male cone that forms on most branchlet tips. Pollen sacks (microsporangia) can be seen at the base of the cone scales, the pollen from which is carried by the wind to hopefully intersect and fertilise tiny female cones, which are both produced on the same plant. The mature seed is only released after a bushfire, or if the tree or any part thereof that dies.