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Fresh eyes, new discoveries

It’s something of a cliché, but sometimes it really does take a fresh pair of eyes to spot the difference – or, in the case of a new Victorian species of Brachyscome discovered among RBGV’s dried plant collections, the fresh eyes of a visiting research team from Japan.

The discovery of Brachyscome dichromosomatica was made when a visiting research team from Japan, including Professor Emeritus Kuniaki Watanabe (Kobe University), Dr Shota Sakaguchi and Hiroyuki Kondo (both from Kyoto University), inspected all 4,397 Brachyscome specimen sheets held in the Herbarium.

Hidden amongst the Brachyscome lineariloba specimens was a new species for Victoria. Closely allied to the common mallee species (B. lineariloba), on closer inspection B. dichromosomatica is quite distinct.

The new Victorian record is from Neds Corner, a Trust for Nature conservation reserve in the far north-west corner of the State. Its distribution was known and recorded from fairly close to the Victorian border in both New South Wales and South Australia, so the discovery  has filled a gap in the geographical and floral map.

The Japanese research team is studying phylogeny and chromosomal evolution in Brachyscome and, having previously studied closely the Brachyscome dichromosomatica–lineariloba complex, they readily spotted the subtle distinguishing characteristic – a well-defined ring of ligulate florets (these are the outer ‘petals’ on a daisy flower), compared to the tiny ligulate florets of D. lineariloba.

Remarkably, as the species name suggests, Brachyscome dichromosomatica has just two pairs of chromosomes, and according to Professor Watanabe there are only five plant species known to have such a low number of chromosomes: another daisy (Haplopappus gracilis), two grasses (Colpodium versicolor, Zingeria bibersteiniana) and Ornithogalum tenuifolium, a member of the Asparagus family.

Perhaps even more remarkably, the Australian jumping-jack ant or jack-jumper (Myrmecia pilosula), widely detested for its savage bite, has just a single pair of chromosomes – the only animal known to bear such an honour.

Read more at VicFlora