Life in the pond: Chara

Chara globularis stalks and side branches

An interesting green alga, about 100 mm tall, growing on the bottom of the Botanic Garden’s ponds has appeared — it is Chara globularis.

Carolyn Ricci and Bob Baldock from the State Herbarium’s Phycology Unit report that the alga is often found in calcium-rich waters. Its central stalks are ribbed with cells that accumulate lime crystals, and there are rings of stiff side branches ending in points.

Chara globularis, close-up

The female organs are bottle-shaped, wrapped in five twisted cells and stoppered with a cellular plug. Male organs in this species are spherical, lurk just beneath the females and are orange.

Who said that algae are simple life forms?

No seminar in March

We regret to announce that due to lack of venue, the It’s All About The Plants seminar on 4 March, 2014 has been cancelled. The following seminar will take place on 1 April, 2014.

New Journal article, Feb. 2014

Today, 18 Feb. 2014, the first paper of Vol. 27 (2014) was published in the online edition of the Journal of the Adelaide Botanic Gardens.

Placynthium australiense sp. nov. (lichenised Ascomycota, Placynthiaceae) from South Australia
by P.M. McCarthy & G. Kantvilas
describes a new species of lichen from the Murray River region of South Australia.

To access content of all volumes of the Journal of the Adelaide Botanic Gardens since 1976, please visit the journal’s web-site at flora.sa.gov.au/jabg.

Placynthium australiense

Interesting algae in the lake

Botryococcus braunii

This photograph shows a microscopic image of Botryococcus braunii. Hon. Research Associate Bob Baldock reports that this interesting algae has appeared within floating rafts of filamentous green algae (mainly Oedogonium sp.) in the storagepond of the new Adelaide Botanic Gardens’ First Creek Wetland.

Botryococcus braunii grows as a colony of egg-shaped cells within a tough, gelatinous sheath: individual colonies may cling together by gelatinous strands. Although a member of the green algae, it, and its colonial matrix are usually coloured yellow or brown. Individual cells store oil droplets, and this feature is currently being researched as a possible source of bio-fuel. — But don’t worry, there is insufficient to set the pond alight!

Bob Baldock is a long-time associate of the State Herbarium of South Australia, responsible for the creation of the Algae Revealed fact-sheet series on marine algae of southern Australia.

The invading flora: a regional account of the assault

Recently, State Herbarium botanist Peter Lang has compiled the numbers of vascular plants occurring in the wild in South Australia for 2013. There are 4,940 taxa (= species, subspecies & varieties) in the state, of which 1,267 taxa (25.6%) are naturalised alien plants (weeds). A further 232 taxa (4.7%) are questionably naturalised: these are, for example, plants that are found in cultivation and have escaped, but it is not proven whether they will maintain their wild populations. Including these the total for alien taxa is 1,499 (30.3%), or almost one third of plants found in the State.

The graph below depicts the numbers of plants for each of the 13 botanical regions (as used by the State Herbarium). The lowest number of introduced taxa is found in the NW (North Western) region of the State, with only 5.9% of naturalised and questionably naturalised plants. The SL (Southern Lofty) region, which includes Adelaide, the Adelaide Hills and Fleurieu Peninsula, has the highest number of alien plants, 46.4%. As expected, more remote regions, away from large settlements, have fewer naturalised and questionably naturalised taxa.

Weeds are not only introduced through agricultural practices, but also escape from gardens. Plants listed as questionably established highlight potential weeds of the future and warrant monitoring or control, to prevent them becoming established.

Click here to see the original data.