Native Pig-Face, Carpobrotus rossii

Park of the Month in Feb. 2017 was Hallett Cove Conservation Park

Herbarium sheet – before the plant is dried, of Carpobrotus rossii. Photo: State Herbarium.

Among the amazing geological features of an ancient landscape a plant which might go unnoticed except when flowering is the native coastal species of Pig-Face, Carpobrotus rossii. In fact, Carpobrotus (Pig-Face) is a world-wide genus of succulent plants, with species native to South Africa, Australia, South America and California.

In South Australia there are four species of Carpobrotus and two species in a closely related genus Sarcozona. Carpobrotus modestus and C. rossii are native to South Australia as are the two Sarcozona, S. bicarinata and S. praecox.

In the coastal areas of Hallett Cove the native species, Carpobrotus rossii is an important member of the ecosystem forming dune protecting ground cover and fruits that animals eat.

Carpobrotus edulis flower type, this plant likely to be a hybrid backcross to C. edulis. Photo: C. Brodie.

However, South Australia also has a species of Carpobrotus that is an introduction from South Africa, Carpobrotus edulis, which is listed in the Global Invasive Species Database for 24 countries.

Honorary Research Associate Dr Hellmut Toelken from the State Herbarium of South Australia has been researching the taxonomy of this group and discovered that some pairs of species may form hybrids in South Australian locations. A partnership between the State Herbarium, The University of Adelaide and The Samphire Coast Icon project and Adelaide and Mount Lofty NRM applied molecular techniques to work out what was going on. The DNA analysis that this project conducted revealed that Dr Toelken was correct, and in fact there are many hybrids forming between the local native species and the introduced one. Hybrids are widespread in many areas, in fact where the two species come into close proximity.

A big problem is that while the yellow flowered C. edulis is relatively easy to identify, the hybrids in South Australia appear to be typically pink flowered plants.

Hallett Cove Conservation Park is well known for its geological and archaeological features, and is just outside of Adelaide.

From the parks webpage:

‘In the park ‘glacial pavements’ show evidence of a large glacier that covered the park and surrounding areas 280 million years ago when Australia was part of Gondwana. Over the past 600 million years the Park has undergone a number of changes from being beneath the sea and covered in an ice sheet to being a mountain range. Throughout the Park there is informative signage along the trail that help you understand the story of Hallett Cove Conservation Park.’

F1 C. rossii X C. edulis South Australia. Photo: C. Brodie.

More information is available on the Carpobrotus hybrid project:  Waycott, M. (2016). Hybridisation in native pigface, Carpobrotus rossii. (State Herbarium of South Australia, Adelaide). 8 pp. ISBN 978-1-922027-47-4

The Sea Nymph — Amphibolis antarctica a seagrass only found in the cooler ocean waters of Australia

The Park of the Month January 2017 was Encounter Marine Park

Sea-nymph, Amphibolis antarctica, South Australia in foreground. Photo: KJ van Dijk.

Our plant of the month for January, the ‘sea nymph’, Amphibolis antarctica, is an Australian endemic species of seagrass which typically occurs in cooler temperate oceanic waters. The earliest collections of Amphibolis antarctica are likely to have been made on the Baudin expedition which were then used by P. Labillardière in 1807 to describe the new species. Plants of the genus Amphibolis are characterised by having a cluster of leaves at the end of sinuous, wirey stems.

Amphibolis antarctica is often found growing attached to rocky or harder substrates, the rhizome and root mat helping them attach by growing into crevices and enabling plants to cling to locations where other seagrasses might become detached. For this reason, Amphibolis antarctica is associated with rocky reefs, limestone and granitic underwater reefs. Amphibolis plants create a significant 3 dimensional surface area for other plants and animals to use as their home and these epiphytes and epifauna are often very obvious elements of local communities.

There have been declines in areas of Amphibolis antarctica and its sister species Amphibolis griffithii closer to the Adelaide Metropolitan region historically, and some areas on Kangaroo Island. The declines have been shown to be due to poor water quality.

Amphibolis plants produce unusual seeds – they in fact form seedlings which remain attached to the mother plant for months after they are formed and then detach and float away to settle as seedlings. This allows them to travel long distances and gives the seedlings of the sea-nymph a better start in life. Research in partnership between the State Herbarium, the University of Adelaide and Murdoch University is studying how genetically diverse populations are and how far the seedlings might travel. A field guide is available that explains more information on Southern Temperate Seagrasses including the sea-nymph.

The Encounter Marine Park is covers 3,119 square kilometres of the Gulf St Vincent and Coorong Marine Bioregions and extends from southern metropolitan Adelaide waters around the Fleurieu Peninsula and past the Murray Mouth to the Coorong coast. A baseline report on the Encounter Marine Park published last year summarised our knowledge of the reserve.

This Encounter Marine Park region contains some very large areas of seagrass and supports numerous fisheries species and other species of conservation value such as the Leafy Sea Dragon. In fact, the density of leafy sea-dragons was surveyed by divers using photo-identification methods near West Island, with density estimated at 57 per hectare (see baseline report on EnviroData SA).

Cryptandra tomentosa. Photo: C. Lindoff, CC-BY 2.5 AU (natureshare.org.au).

The State Herbarium of South Australia has chosen Cryptandra tomentosa Lindl. as Plant of the Month. It is widespread in south-eastern Australia and also occurs in DEWNR’s Park of the Month for March 2017, Anstey Hill Recreation Park. The Park includes the site of the former Newman’s Nursery, which featured in an article by Taplin & Symon, published in the Journal of the Adelaide Botanic Gardens (21.3mb PDF).

Cryptandra tomentosa was named by British botanist John Lindley from plant material collected by exporer Thomas Mitchell in the Grampians, Victoria. From the account of Mitchell’s journey, it is clear that the collections were made on 15 July 1836, when the expedition party was on Mt Willam. The new species was described to be “remarkable on account of its downy leaves”.

Typical Cryptandra tomentosa plants are small shrubs, with inconspicuous white flowers clustered towards the end of the branches; the flowers tend to turn reddish or pinkish when older. Leaves are narrow and up to 5 mm long, rarely longer, the margins are usually tightly rolled so that only the midrib is visible on the lower surface. The upper surface of the leaves is glabrous and smooth, however, not “downy” as described by Mitchell. What is hairy in C. tomentosa are the stems, especially young ones, and the lower surface of the leaves, which is usually obscured. Some early botanists believed the red- and white-flowered forms were different and described them as separate species, e.g. C. erubescens F.Muell. was published as a name for a red-flowered specimen of C. tomentosa.

Typical Cryptandra flower. Modified from K.R.Thiele, J. Adelaide Bot. Gard. 21: 64, Tab. 1 (2007).

Flowers in the plant family Rhamnaceae are quite unique in that the petals are placed opposite the stamens (obhaplostemonous) and “hooding” the anthers, whereas in “standard” angiosperm flowers, the stamens are opposite the sepals. Sepals in Rhamnaceae are colourful and are the most conspicuous parts of the flower; the typical condition for angiosperms is that the sepals are green and smaller than the petals. Most Rhamnaceae flowers also have a conspicuous nectar-secreting disk that covers or surrounds the ovary. In the genus Cryptandra, all flowers are also surrounded by numerous brown bracts.

C. tomentosa, older flowers turning red. Photo C. Clarke, CC-BY 2.5 AU (natureshare.org.au).

The name C. tomentosa was applied wrongly to many plants in south-eastern Australia, even Western Australia. The taxa related and similar to C. tomentosa and C. amara Sm. are currently being revised by State Herbarium botanist Jürgen Kellermann and his colleague Frank Udovicic from the National Herbarium of Victoria. Some taxa that had been named in the past as C. tomentosa are now known as Cryptandra sp. Floriferous, Cryptandra sp. Hiltaba, Cryptandra campanulata Schltdl., C. nutans Steud. and C. myriantha Diels (interestingly, the only species of Cryptandra to occur on both sides of the Nullarbor).