Parakeelya habitat

It's somewhat of a mystery why a showy and hardy plant like Calandrinia balonensis is not more widely cultivated. Possible reasons are that plants tend to be short-lived, and more than one clone has to be grown to set seed. Also, seed can be tricky to germinate. In the wild, it's common and widespread, at least in arid regions. Finding out how it succeeds naturally could make it easier to grow as a cultivated plant.
Calandrinia remota in western NSW

See other people's in-habitat photos of P. balonensis  at Owen Springs, NT,  somewhere in Central Australia, and off Adventure Way NE of Innamincka ~12 km into QLD which features a plant with bicoloured flowers.
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Clouds of native bees pollinate the flowers. Then they wilt and the flower stem turns downward. However, as the seed capsuIes mature and open, their stems tend to turn up again. This helps the forty or so seeds be retained for a little when the flask-shaped capsules open (photo below).


 
My initial attempts to germinate seed produced less than 1% germination. However, Seeds of South Australia advised me that Kew Gardens in London had found that the seed coat is impermeable to water. After nicking of each seed with a scalpel, while observing under a dissecting microscope, they had 80 - 90% germination. Too lazy to do this myself, I soaked some seed in concentrated sulphuric acid, a commonly used method for making resistant seeds permeable water. This sounds drastic, but it works with many seeds that have tough, impermeable coats. The photo below shows a germinated seed after soaking for 20 minutes in just enough 98% sulphuric acid to cover the seed, followed by tipping the acid + seed into plenty of water. Be careful if you do this - wear eye protection and never add water to sulphuric acid as the water will boil and spatter acid. Pour the acid + seed into plenty of water instead. After tipping the seed into water, I washed it by repeated decantation. Some seed floated off during washing and I assumed that this was probably empty. The washed seed was germinated on damp paper towel at 18 - 22 C under LED lights here.

It was obvious which seed had become permeable to water, because it swells to about twice its original size on the damp towel. The photo below shows a magnified seedling with the cotyledons starting to separate, 9 days after putting the acid-treated seed on damp paper towel. The scale bar is 1 mm.
 Calandrinia balonensis germination after sulphuric acid scarification

Here is a young plant of Calandrinia balonensis growing in piles of red sand graded from a dirt road north of Bourke, NSW.  Perhaps it's advantaged by the road grading, because plants were most plentiful in the banks of sand along the road, while they were more scattered where there had been less disturbance. The plants were all of a similar age, perhaps having germinated with the onset of the unusually wet autumn/winter of 2016. This had broken a drought of several years. By mid-September, when this photo was taken, the young plants were just starting to flower. It was still so wet in this normally arid area that getting the car bogged was a constant hazard.

Seedlings form a leaf rosette, anchored by a distinct taproot. Dandelions and lettuce have a similar habit until they "bolt" at flowering stage, when they send a flower stem up from the centre of the rosette. This parakeelya species occasionally does this, with the central shoot elongating out of the rosette and producing flowers. However, it's more usual for flowering shoots to come from the lateral buds of the rosette, like the plant in the photo. These flowering shoots can be detached and rooted as cuttings. This provides a convenient method of propagating plants. However, the cuttings tend to flower prolifically over summer at the expense of producing leaves. 

A short life seems typical for C. balonensis. Of some seven seedlings that I had over the 2016/17 summer, only one kept its initial rosette after flowering through the summer. It produced new flowering shoots over winter and, by mid August, had started to flower again. I've had better results at preserving the central rosette in 2018 by ruthlessly removing the flowering shoots in the autumn. Short segments of the flowering shoots that have at least some leaves have taken as cuttings. Fleshy stems  without leaves seem reluctant to root.

 A seedling of P. balonensis germinated after surviving mechanical seed scarification between pieces of fine enery paper. It's magnified to show the fleshy cotyledons, each about 4 mm long. Although I was able to get a few seedlings by this method, I found it difficult not to grind many seeds to flour. The sulphuric acid treatment has produced a few seedlings using seed 3 months after harvest but, like mechanical scarification, nowhere near 100% germination. In many desert annuals, seed needs a period of after-ripening that can be a year or more. A possible explanation is that this species combines two methods of delaying germination, an impermeable seed coat and a period of after-ripening. The two delays on germination could help it survive the unpredictable droughts that are such a feature of Central Australia.

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