Native ‘Easter lilies’

Calostemma purpureum. Photo: L. Jansen

February and March are a tough time for plants; the heat of summer has killed off annual grasses, and few native plants are in flower. It is at this time that, almost miraculously, the flowers of the Calostemma purpureum (garland lily, purple bells) emerge from the hard and parched ground, a cluster of purplish-pink flowers at the end of a fleshy stalk — and not a leaf to be seen.

This species has been chosen as this month’s Plant of the Month: it is a native bulbous herb of grassland and open woodland habitat that features prominently in the current Park of the Month, Shepherds Hill Recreation Park.

When encountered for the first time, Calostemma is often mistakenly thought to be an introduced plant: its robust and succulent appearance simply does not fit the stereotype of a native. In many features it resembles a smaller version of the garden plant belladonna lily (Amaryllis belladonna) and is in fact a member of the same family (Amaryllidaceae). However, Calostemma is uniquely Australian and confined to the eastern part of this continent.

C. purpureum, flowers and close up showing corona. Photo: P.J. Lang

Although their initial appearance is usually triggered by a fall of rain, their flowering and growth is sustained by a bulb about the same size as that of a daffodil. The bulbs are buried deep, as much as 30 cm below the ground, having been pulled down a little further each year by contractile roots. By the end of summer each mature bulb is primed with three almost fully developed flower stalk buds awaiting the signal to expand as soon as some rain arrives.

These plants have reversed the usual cycle of a spring flowering after winter vegetative growth prevalent in Mediterranean climates. Instead, Calostemma behaves like a number of other autumn flowering species where flowers first appear on their own, with the leaves to follow later. Calostemma remains in its vegetative growth phase through winter and spring when conditions are much more favourable, until eventually the fleshy strap like leaves die back again for summer.

C. purpureum, plants weighed down with fruit. Photo: P.J. Lang

One of the most fascinating aspects of the garland lily’s ecology concerns its seeds, strictly ‘pseudoseeds’, which behave as bulbils. These are green, water-rich, fleshy but firm and similar in appearance to a large pea. The fruit itself is reduced to a mere papery shell surrounding the seed. The flowering stems dehydrate as the fruits swell, leaning over under their growing load. Soon the stems become prostrate and release the fruits, so dispersing them by a radius equivalent to their height. This limited reach is enhanced by the ability of the seeds to roll down-slope, to float in water, and perhaps sometimes to be carried and dropped by birds.

Perhaps the most remarkable feature of these propagules is their lack of dormancy. They start to ‘germinate’ as soon as they are mature and do so without water, drawing on the moisture contained within them. The cotyledon with root and shoot sometimes even emerge while it is still attached to the plant.

Calostemma was first described by Robert Brown in 1810. The name is derived from the Greek καλός [calos], beautiful, and στέμμα [stemma], garland or crown, which refers to the conspicuous golden corona in the centre of the flower formed by the fusion of the six stamens.

Calostemma purpureum often grows in dense colonies, and can create a mass of pink when in full flower. Flower colour on individual plants varies from a purplish maroon to pale pink and occasionally white.

C. luteum (right, photo: SA Seed Conservation Centre) and C. abdicatum (left, photo: P.J. Lang)

The genus has two other species, both found in South Australia. The slightly larger yellow-flowered Calostemma luteum (yellow garland-lilly) occurs in the Riverland and Lake Eyre drainage systems. The aptly named Calostemma abdicatum (the epithet is from the Latin abdico to disown, renounce or resign) is remarkable in lacking the definitive corona, from which the genus takes its name. It is endemic to the Everard Ranges in the Anangu Pitjantjatjara Yankunytjatjara Lands in the north-western region of the State, and was described as a new species by State Herbarium Botanist Peter Lang in 2008.

The State Herbarium has chosen Eucalyptus camaldulensis Dehnh. (river red gum), as Plant of the Month for February 2016. It is an iconic tree across South Australia and in the Murray River National Park, this month’s Park of the Month.

River red gums at Katarapko Island, Murray River National Park. Photo: Peter Canty.

Eucalyptus camaldulensis has one of the widest natural distributions for an Australian tree, and is one of the most commonly cultivated eucalypts around the world. Accordingly this wide distribution has produced much variation, and seven subspecies are now recognised, E. camaldulensis subsp. camaldulensis occurs along the Murray River.

The habitat of E. camaldulensis is typically along watercourses and floodplains, however the species also occurs on hills in the Mt Lofty Ranges. Its tolerance to flooding is in part due to its massive size and its ability to grow roots quickly and produce adventitious roots on submerged stems. One study has shown that 9 month old cloned plantlets could produce more than 8 km of roots. Its seed floats for some time and is released predominantly during flooding months.

“Spirit of endurance”, Harold Cazneaux well-known photograph of a river red gum near Wilpena Pound, Flinders Ranges. Art Gallery of NSW.

The trees ability to attain massive sizes with hollows makes it an important habitat for many animals (regent parrots, bats, possums, goannas) and insects (49 species have been recorded from a E. camaldulensis forest canopy on the river). Submerged roots and branches are important to many fish like the murray cod. Many intimate fungal associations also exist, one example being the basidiomycetous yeast Cryptococcus gattii. This is released from the tree during flowering and has resulted in the deaths of immune suppressed people (pdf) in Australia and around the world where E. camaldulensis grows, the spores being transported to other countries with the seed.

The age of large trees is difficult to ascertain in part due to the natural hollow formation, some authors indicate ages from 500 to 1000 years. The long history of human use of the tree is still very evident from all the Aboriginal Nations along the river, with many canoe and shield trees found on living and dead trees of considerable age. More recent use has seen the wood used for heavy construction, railway sleepers, furniture and firewood. Honey and a good source of pollen for bees is also significant.

Canoeing under river red gums along Katarapko Creek, Murray River National Park. Photo: Juergen Kellermann.

The name relates to the cultivation of the type specimen at Camaldoli near Naples in Italy in 1832. However study of the type indicated that it was another eucalypt, possibly quite unrelated. An earlier used name, E. rostrata Schltdl., was invalid, while a name given by Mueller, E. longirostris F.Muell. ex Miq., was valid. Because the name E. camaldulensis is so widely used around the world, Brooker & Orchard (2008) applied to conserve the name and select a new holotype. This was successful and a Dean Nicolle collection from Currency Creek was selected. The full discussion of this fascinating typification can be found in a paper by McDonald et al. (2009).

Feel free to contact the State Herbarium’s expert on the eucalypt family Myrtaceae, Martin O’Leary (martin.oleary@sa.gov.au), for specific references or more information.

Further reading can be found at:

• J.Williams & J.Woinarski. (eds). Eucalypt ecology: individuals to ecosystems. Cambridge University Press. 1997.
• http://www.anbg.gov.au/cpbr/WfHC/Eucalyptus-camaldulensis/
• Nicolle, D. (2014). Myrtaceae (partly) (version 1) [10MB PDF]. In: Kellermann, J. (ed.), Flora of South Australia (ed. 5). 102 pp. (State Herbarium of South Australia: Adelaide). flora.sa.gov.au/ed5
• Anon. (2010). River red gum woodlands of watercourses and floodplains. (SA Arid Lands NRM Board: Port Augusta). [560KB pdf factsheet]

The State Herbarium has chosen Posidonia sinuosa Cambridge & J.Kuo. as the plant of the month for January, 2016 and it is found the Encounter Bay Marine Park.

Posidonia sinuosa is a species of seagrass that is endemic to southern Australia and does not occur further East than the SE of South Australia. It forms very dense, stable meadows, however this species of seagrass has been listed as Vulnerable to extinction on the IUCN Redlist due to its slow growth rates, infrequent recruitment and highly fragmented habitat across its range. Posidonia sinuosa plants have very long leaves and dense rhizome mats, and as a result the meadows form important habitat for many animals and marine algae which use the plants as a home base. This species of seagrass is typically found in the relatively protected areas of South Australian waters up to around 20 m in depth. Posidonia sinuosa forms floating fruits in summer and along with the fruits of other species of Posidonia, may be often found littered along the beaches at certain times of the year.

Posidonia sinuosa meadow in Yankalilla Bay. © photo by Simon Bryars

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Acacia alcockii, habit

This month’s Park of the Month is Coffin Bay National Park on southern Eyre Peninsula. The State Herbarium has chosen Acacia alcockii Maslin & Whibley (Alcock’s wattle) as the Plant of the Month, as the species is endemic to southern Eyre Peninsula. It grows in coastal and near-coastal areas, mainly in sand over limestone. Alcock’s wattle is listed as ‘rare’ for South Australia.

The species was described by Bruce Maslin and David Whibley in 1987. It is a bushy shrub, 2-3 m in height, and can be distinguished from its closest relatives, A. anceps and A. leiophylla, by the combination of racemose inflorescences consisting of small pale yellow globular flower heads, and transverse seeds in the pods (see line drawing from worldwidewattle, below).

The collector: C. Ray Alcock (1921-2015)

The wattle is named after Ray Alcock, one of the State Herbariums most prolific collectors, who died earlier this year. Besides A. alcockii, he is also commemorated in the species name Rumex alcockii Rech.f., now a synonym of R. brownii Campb.

Charles Raymond Alcock (1921–2015) followed his father’s footsteps into the field of agriculture. Ernest Simpson Alcock was an early (1904) graduate of Roseworthy College, where his son was later to study as a scholarship student. Ray’s childhood was spent on the Kybybolite Experimental Farm in the south-east of SA, where his father was employed as a supervisor. From Roseworthy, Ray left to serve in World War II, later with the RAF in Britain, gaining a DFC for his efforts.

Acacia alcockii, phyllodes and pods

Although Ray also gained a diploma in dairy studies from Hawkesbury College and spent his early working in the dairy industry, he turned his attention to plants (and specifically weeds) in the 1950s. Plants and nature conservation became his passion from then until his death, and he became a prolific collector for the State Herbarium, which holds around 12,000 specimens under his name. He joined the Nature Conservation Society of SA in 1964, only 2 years after its formation. He was nominated for membership by then head of the State Herbarium, Dr Hansjörg Eichler.

Most of his earlier plant collections are from Eyre Peninsula, where he was employed by Local and State Government as a Weeds Officer for the Eastern Eyre Peninsula Weeds Board / Lincoln Council and the Department of Agriculture. His collections were certainly not restricted to weeds, and early correspondence with the Herbarium indicates that he found a number of plants not previously recorded for the Eyre Peninsula region. In 1971 he was transferred to the head office of the Agriculture Department in Adelaide, where he was employed as an agronomist with the Weeds Section. He was the Local Government Liaison Officer for some time and latterly specialised in weeds identification and advice with the Pest Plants Commission, building up an extensive herbarium of weed specimens, which has since been transferred to the State Herbarium.

In his retirement he worked with the State Herbarium as a volunteer and collected widely around Australia during his holiday trips. Plants even extended to his hobbies, as he was an avid and talented wood carver.

worldwidewattle.com

Correa glabra var. leucoclada, photo by P.J. Lang

We kick off our new series Plant of the Month with Correa glabra var. leucoclada (rock correa), which is a plant characteristic of Morialta Conservation Park, DEWNR’s Park of the Month for Nov. 2015.

Rock correa is found in the southern Mt. Lofty Ranges and eastern and central New South Wales. In South Australia it is confined to sheltered rocky habitats and steep gorges, mainly at Morialta, Torrens Gorge and Sturt Gorge. (Because of its restricted distribution it is listed as “rare” in S.A.) Morialta C.P. probably conserves the largest of these populations and you are bound to encounter it there, especially if you are on the walking trails near the waterfalls. With its yellowish-green tubular flowers the variety is adapted for pollination by honeyeaters: their long bills they are able to reach the nectar at the base of the flower.

Correa glabra var. turnbullii, photo by L. Jansen

Correa glabra var. leucoclada is related to the more common and widely distributed C. glabra var. turnbullii (narrow-bell correa), which is found on rocky hills and plains in dryer habitat. Rock correa is distinguished from var. turnbullii by its yellow-green rather than red flowers, and the underside of the leaves and stems with more obvious scurfy hairs (giving a pale almost whitish appearance) rather than appearing smooth.

Like the rock correa, other genera of Australian plants such as Eremophila (Emu-bushes) and Prostanthera (Native Mint-bushes) have evolved species with tubular flowers adapted for bird-pollination, and furthermore these also have some taxa with red flowers and others with greenish flowers. (In contrast the insect-pollinated species of these genera have more open flowers that are usually white or violet in colour.)