State Herbarium Hon. Associate Bob Baldock from our Phycology Unit provided these photographs of Thuretia australasica.

This small, red alga was found attached to the stems of a seagrass collected at the Head of the Great Australian Bight in 2010. At first glance the plant appears mundane, even uninteresting.

But, under the microscope, a delicate mesh of microscopic threads forming the small, hollow, cylindrical plant body is revealed, another example of the surprises awaiting us in the microscopic world. (Note that the white, glassy particles are sand grains trapped in the mesh and not part of the alga.)

Click here for a detailed description of the species from the online version of Prof. H.B.S. Womersley‘s Marine benthic flora of southern Australia.  More images can be found in Bob Baldock’s Algae revealed fact-sheet “Pictured key to some common re-mesh algae of southern Australia” (1.3MB PDF).  A detailed colour plate from W.H. Harvey‘s Phycologia australasica is available from the Internet Archive (under the name Thuretia teres).

State Herbarium Hon. Research Associates Hellmut Toelken and John Jessop have yesterday examined flowering branches of Phyllostachys aurea Rivière & C.Rivière (fishpole bamboo) from Dr Toelken’s garden. This bamboo species only sets flowers every 15–20 years. As the State Herbarium does not have flowering material of the species preserved in its collection, herbarium specimens were prepared from these branches.

Phyllostachys aurea, inflorescence.

The long interval between flowering in bamboos has perplexed many botanists over time. If you want to know more about this, the US Forest Service gives an overview for P. aurea, and Janzen (1976) provides a comprehensive review for all bamboo species. According to this article, the longest recorded intervals between flowering are for Bambusa vulgaris (150+ years), Chimonobambusa quadrangularis (100+ years) and P. bambusoides (120–130 years). Many bamboo species seem to die after flowering, but reports for P. aurea are not conclusive, some authors claim that plants die, others state that they die down to the rootstock but can resprout.

Phyllostachys aurea is native to China and has been introduced to many countries around the world. It is mainly used as an ornamental plant. The species has been listed as a weed in many countries, due to its invasive nature. In Australia, it is a declared weed in Queensland and New South Wales; it is prohibited in the Australian Capital Territory. It is recorded in the South Australian Census of Plants, Algae and Fungi as possibly established in the Southern Lofty (SL) region. It is not listed to occur in the other States and Territories, but parts of Victoria also treat it as a weed (e.g. the Alpine Shire).

Phyllostachys aurea, inflorescences, shoots and leaves.

When it flowers, then usually all plants from the same clone come into flower, and as many horticultural plants are derived from the same parent clump, it can be expected that many Phyllostachys aurea plants in South Australia or even other parts of Australia will be flowering at the moment (or any time soon). If you have bamboo planted in your garden, then have a look…

State Herbarium Hon. Research Associate Bob Baldock reports on the following two images.

They depict not a sea shell, or a coral, but a red coralline alga — no more than 2 mm tall! It was found scattered on the fine branches of a brown alga, Cystophora (2.6MB Algae Revealed fact-sheet) from 20 m deep at Pearson Island, off Ceduna, by the Marine Park Monitoring Group in March 2015. Finding a name for it is proving difficult. It doesn’t fit exactly into diagnostic features of known species. The closest match that has been suggested is Hydrolithon farinosum (link to species entry in the online version of H.B.S. Womersley‘s Marine benthic flora of southern Australia).

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A fine pale yellow dust has recently been seen coating cars and floating on puddles: pollen. This has led to enquiries being made to State Herbarium staff and discussions on local media. Samples were collected by staff member Carolyn Ricci and analysed under high magnification with a compound microscope and an electron microscope.

SEM of opening Acacia pycnantha anther with pollen polyad leaving the anther (arrow).

Wattle day is September 1^st, and the national floral emblem, Acacia pycnantha has been flowering strongly for some time. The favourable season this year has also resulted in many Acacia species flowering together when they are more typically staggered. These prominent blossoms occur around the time that some people start to experience hay fever, but other less obvious plants are having a great season as well: pines are producing large amounts of pollen from their strobili and oaks are producing pollen from their catkins. These wind pollenated species must produce huge amounts of pollen to achieve successful fertilisation by chance, so the pollen’s ability to float in the wind over long distances is advantageous. Acacia pollen is transported by insects, so the pollen tends to be heavy and sticky. Wattle blossoms are made up of hundreds of tiny flowers that effectively become pollen brushes to its visitors. Acacia pollen is also distinct in that it forms polyads, balls of pollen commonly in multiples of four. In comparison pine pollen comes as single grains with two air sacks to help it float in the wind.

Light microscope image of pine (left: with two air sacs) and wattle pollen (right: polyad consisting of 16 pollen grains).

The images here show what was found, large amounts of pine pollen with its distinctive twin air sacks. A polyad of Acacia pycnantha is included for comparison, this was collected from a blossom from the Adelaide Hills and the polyad physically removed for examination. Acacia pollen was not found amongst the pine pollen but should be present in lower amounts.

SEM of pine pollen.

Grass pollen is well known for its strong allergic reactions. This wind pollinated group is likely to become more prevalent in the next few weeks! Enjoy spring.

A radio interview with State Herbarium staff member Martin O’Leary on pollen was conducted on ABC South East SA on Thu., 4 Sep. 2014. It is available online on the ABC web-site.