Recently Debbie Reynolds gave a fascinating talk about Spiny Rice-flower to a small group at Federation University Ballarat. These are my notes from that talk.

There are about 150 species of pimelea (rice flowers) which are mainly found in Australia, New Zealand, Timor and New Guinea. In Australia there are 110 endemic species and of these 18 are listed as rare and threatened. The ones seen in basalt derived grasslands are Pimelea humilis, P. curviflora, P. glauca and P. spinescens subsp. spinescens.

Pimelea spinescens subsp. spinescens is listed as critically endangered and only found in Victoria. The common name is Spiny Rice-flower which relates to the end of the stems which are pointed or spine tipped. It is a small spreading shrub to 30cm, winter flowering and usually seen from April to August.

The best time to look for it is when it is flowering especially if the area has been burnt late summer to remove the grass. Otherwise it is very hard to find. There are still probably populations of this pimelea to find on the Victorian Volcanic Plain, Victorian Midlands and Riverina. Recent genetic studies indicate the populations in the three bioregions are different enough that current recommendations are that the seeds are not to be used outside that bioregion without further research. Pimeleas do look different in each region.

The plants are usually dioecious, meaning there are male and female reproductive structures on separate plants but sometimes plants are hermaphrodites, having both male and female reproductive organs on the same plant. This relates usually relates to water availability.  If you see orange on the flowers they are male. The female flowers do have small anthers but are less showy. This may be a protective mechanism to stop them being eaten.

Insects carry out the pollination and the winter flowers are important for a range of grassland insect species. It is believed that this pimelea fulfills an important ecological role as not much else is flowering. The 3mm fruit is about the size of a grain of rice and sometimes fleshy fruit is produced. It is an oily seed and the test for viability is to squash them in a paper bag. Gibberellic acid is used to test how well the seeds will germinate. If growing them from seed don’t be too hasty to decide that have all germinated as seedlings will appear over a long period. Germination take place in winter. Currently work is being doing to see how the plants go with direct seeding.

The advice is to take advantage of a germination event. There is initially more seedlings than will survive and these could be potted up and planted elsewhere. It needs to be a group of 100 -300 plants, more the better so they may form a viable population.

Seedlings produce a taproot that can grow down 50-60cm and laterals spread up to 150cm. To establish plants into a grassland they need to be from seed as cutting grown plants don’t produce the same root system. It is the root system that sees this pimelea live to about 50-60 years. They may live longer but this has yet to be determined. So together with Feather Heads Ptilotus microcephalus, Spiny Rice-flower should be considered the trees of the grasslands.

Reduction in the grass and other plants growing around the pimelea (biomass) is very important for the ongoing survival of this species. They are able to with stand a hot fire and need a fire every 3-4 years.

The winter after a burn is a good time to do surveys for the species as they are easier to find. If possible when a population is discovered and counted it should be left for a while and many more plants will appear especially after a burn. Survey 6-12 months later.

Spiny Rice-flower are found on road and rail reserves, cemeteries and on private land that has low intensity grazing and no cropping. The plants are not poisonous and are palatable to stock and protecting the populations after a burn will help to protect the soft growth. Rabbit control is essential. Many of these isolated populations on Crown land need a Friends Group to look after them and funds are usually available.

An example of this is Skipton Common which is managed by the Ballarat Environment Network (BEN). A seemingly small population is now considered to have more than 1000 plants after some dedicated counting and tagging. It is anticipated that even more will be discovered next week when members of the Field Naturalists Club of Ballarat join with BEN to conduct another count. Funding has been received which has allowed new fencing to better manage grazing.

Many of the plants still under threat are in the urban growth corridors. Recently about 400 plants were to be lost in a rail upgrade so work was carried out to translocate about 300 plants with a large plug of soil using a large tree spade. Seed was collected as well. The success of various translocation methods was reviewed in 2013 and the methods are gradually being refined. The planting site needs to be a viable long term, weed free and activity managed and monitored.

Developers need to factor in a considerable amount of money for translocation if endangered species are found on their site. There are strict processes in place for working with the translocation of threatened species and further advice is available from the Spiny Rice-flower Recovery Team. The team meets 3 times a year and visitors are welcome. They also managed a trust fund that provides yearly grants.

Here are some other the other pimeleas in Australia.