Endangered plant success!

Photos: E. Cousins, Orobanche flower; C. Schultz, Senecio + Orobanche together in one pot.Note the fine white roots of the host plant filling the pot, and the short fat yellowish roots of Orobanche.

Back from the brink of local extinction? …Perhaps a little dramatic, but a very positive sign for the parasitic plant Orobanche cernua var. australiana (Australian broomrape). SA Seedbank’s website says that the only place it grows in the “Southern Lofty” area is Cape Jervis, with only 15 plants recorded. You may remember from our December 2017 Plant of the Month that we found 100s of plants and collected some seed. This year Liz and I both tried germinating Orobanche seed along with its preferred host Senecio odoratus. Imagine my surprise when, sorting Liz’s excess Senecio seedlings for the COOTS September planting at Land’s End, I found an Orobanche poking its asparagus-like head through the potting mix. Only the one so far and it has been carefully planted on one of the sand dunes at the COOTS site, along with another 4 Senecio seedlings that all have Orobanche seed with them. Fingers crossed that more Orobanche plants germinate, including the ones we planted in June at our coastal display garden near the ferry terminal, and several other locations on our site.

COMMON GROUNDSEL

(Senecio vulgaris)

(Photos: E.Cousins; weed growing with other weeds; a stem; close-up of flower head)

Senecios come in many forms … from the rare and unusual to the very common, and from trees through to small weedy herbs such as this one. This groundsel grows to about knee high, with clusters of flower heads at the end of the stems. The individual flowers are only about 1cm long, and don’t seem to open properly, probably because of all those bracts surrounding the petals! Only a millimetre or two of the yellow petals show at the top. There are 15 bracts or more, each tipped with black as can be seen in the 3^rd photo above. There are also lots of little bracts at the base of the flower head, again edged in black. Eventually the flower head produces a fluffy white ball, with the seed on the inside of the ball, waiting to be blown away like dandelion seed. Although this weed is found along our coastlines and in our national parks, it is more common in urban areas, or disturbed sites.

BLADDER SALTBUSH

(Atriplex vesicaria)

(Photos: C. Schultz, sprawling bushes in the foreground; close up of leaves and male flowers)

As their name suggests, saltbushes have a high salt content. They can survive in harsh saline environments. Their ability to survive in a variety of conditions has lead to their becoming part of the diet of many animals…including lamb! Sheep and cattle will graze bladder saltbush readily. This small shrub will grow less than 1 metre tall, but can sprawl. The leaves are quite fleshy unless growing conditions are dry, when leaves might be shed. The grey-green appearance of the oval-shaped, short stemmed leaves is often a give-away for this (and other) saltbushes; leaf margins can be wavy. When you go looking for this one, you will need to look for two versions: the male and the female! The bushes are the same, but the flowers are different. Look for slender but dense spikes of tiny flowers on the newest branches of the male; on the female form, the flowers look more leaf-like, and are about 5mm across.

Return of the pretties! Since the group started in 2012, our aim has been to re-plant the small pretty plants not just gums, she-oaks and wattles. Our June tree planting weekend is in reality shrub, grass and herb planting. Herbs are non-woody plants and many of the local herbaceous “small pretties” are summer dormant which means they die down after flowering and setting seed. Planting these ‘herbs’ is a challenge because they have a short growing season and therefore they are very susceptible to snails and slugs. Annual herbs such as Senecio pinnatifolius must be planted in the season they are grown, but summer dormant perennials such as satin everlasting (Helichrysum leucopsideum) can be allowed to die back in pots and planted out in the following year. We hedged our bets this year with satin everlasting and planted some in August and will let others dry out it their pots till 2018. Thanks to SA seedbank for the hint to collect satin everlasting seed before they mature and leave them in a paper bag to after-ripen. Look out for these and other pretties on the nature trail on Flinders Drive and on the lower loop near the Ferry Terminal.

Photos (C. Schultz): Satin everlasting (Helichrysum leucopsideum); August planting of satin everlastings and other small pretties; pink bindweed (Convolvulus  angustissimus).

CLIMBING SUNDEW

(Drosera macrantha)

(Photos: E. Cousins, Cape Jervis; growth habit, single flower)

Macrantha comes from the Greek ‘macros’ for large and ‘anthos’ for flower, but the ‘large flowers’ here have 5 petals each only 10mm long! However, among the varieties of sundews growing at Cape Jervis, these are pretty large! There are normally only a couple of flowers per plant, clustered on the top of the long, twining stems. In the first picture, they aren’t flowers you can see along the stem, but the leaves! These leaves are cup-shaped, and placed opposite each other. They are covered in fine, soft hairs, with a fringe of longer hairs around the rim of the cup. Sundews are insectivorous; they attract and devour insects using a gooey substance that is exuded by the hairs. This goo glistens, hence ‘drosera’, for dewy!

COMMON CHICKWEED

(Stellaria media)

(Photos: E.Cousins; chickweed growing with other weeds; close-up of one stem)

Chickweed grows in a wide variety of soil types and habitats. It definitely prefers cool, moist conditions so is mostly seen as a winter annual. The slender branched stems intertwine to produce a large mat of foliage, from 5-50 cm tall. The bright green plant is distinguishable by a line of fine hairs on one side of the stems only, between nodes. Leaves are oval in shape, with pointed tips. Lower leaves have no stalk (sessile) but upper ones do (petiolate). The small white flowers are star-shaped (as stellaria would suggest) with 5 petals, each just 3-4mm long. These grow from the tip of the plant, or from joints along the stem.
This weed can be used as a cooling herbal remedy, to ease itchy skin. It is also grown as a food for humans and poultry because of its nutritional value. The plant does contain toxins called saponins, which are poorly absorbed by humans and break down if thoroughly cooked; however they can be harmful to some creatures or if consumed in large quantities. Plants can normally be removed easily after rain by hand-pulling…then maybe feed it to your chickens!

SMOOTH RICEFLOWER

(Pimelea glauca)

(Photos: E. Cousins; growth habit, flower cluster; Cape Jervis)

Come spring, you will see this little shrub flowering freely around Cape Jervis. It has 1 cm long blue green leaves, which are arranged very symmetrically around the many stems. The tiny, creamy-white flowers are arranged in balls about 3cm wide, at the end of those stems … you can see how many little flowers there can be in a flower cluster in the second photo above. Each little flower has 4 petals and yellow-tipped stamens. Under each cluster you will find four leaves (called floral leaves) which are slightly larger than the stem leaves; the inner two should have hairy edges. So look for tidy little shrubs covered in white this spring as you walk around Cape Jervis, and see if you can identify this riceflower.

COMMON BRIDAL CREEPER

(Asparagus asparagoides)

This creeper smothers native plants. Dormant over our dry summers, it sends out long, vigorous, twining stems after autumn rains. These form a thick, dense mat spreading over shrubs and up trees. The root system consists of a central stem, with many tubers attached. Like the leaves and stems above ground, these underground tubers also form a thick mat. In fact, the root system can be up to 90% of the plant’s total mass.¹ So while the creeper is preventing sunlight reaching its hosts above ground, the root system is preventing root growth of plants and seedlings below ground. The green leaves appear in groups on short side branches on the long stems. White flowers in spring are followed by berries which ripen to red. These contain black seeds… one plant can produce thousands. Birds feed on the berries, and excrete the seeds elsewhere, helping the plant spread. Biological controls (rust fungus and beetles) are often used to limit the spread of this pest; digging doesn’t guarantee removal of all the tubers. For more information see the PIRSA fact sheet http://pir.sa.gov.au/__data/assets/pdf_file/0010/145594/Fact_Sheet_BridalCreeper.pdf

¹ Bridal creeper (Asparagus asparagoides) weed management guide, at http://www.environment.gov.au/biodiversity/invasive/weeds/publications/guidelines/wons/a-asparagoides.html

ANNUAL BULBINE LILY

(Bulbine semibarbata)

(Photos: from https://florabase.dpaw.wa.gov.au/browse/profile/1366, https://www.plant-world-seeds.com/images/item_images/000/001/551/large_square/BULBINE_SEMIBARBATA.JPG?1495388088)

Now doesn’t that yellow brighten up a gloomy winter’s day? You might have to wait another few months to see it around though.  The flower of the bulbine lily appears in summer, with 6 bright yellow petals and some inner stamens. Three of these stamens are hairy, which you might be  able to see in the second photo above.  And since the flowers are only about 1 cm across, you might need a lens to see them in real life too! The entire plant is only ankle high, with cylindrical, fleshy leaves (like those of an onion only smaller and brighter). Above the open flower you would normally see more unopened flowers… a bit like a hyacinth: some dying, some open, some unopened flowers along a stem. So come summer, look out for these bright, rare plants along the coast in rocky places, or in the mallee, and enjoy!

GAZANIA

(Gazania rigens, Gazania linearis)

(photo of Gazania linearis from http://www.naturalresources.sa.gov.au/adelaidemtloftyranges)

We thought it would be beneficial to revisit some of the weeds we have looked at before, such as gazanias. These familiar natives of southern Africa can spread easily in coastal communities, because they withstand salt-laden winds and grow well in sandy soils. They also harbor white snails! Gazanias flower in bronze, yellow and orange shades, often with black markings.  Gazania linearis has short, mostly underground stems and dark green leaves, while the stems of Gazania rigens form a mat above ground, and leaves are paler, more silvery. Either can form a monoculture, outcompeting native species for nutrients and moisture.

Gazania is now a declared plant under the Natural Resources Management Act 2004; it can’t be sold at nurseries etc., and it can’t be transported around the state. The Southern Fleurieu Coastal Action Plan gave gazanias a “priority threat rating” of 8, making them the second highest rated weed in the area, behind bridal creeper. If you want to grow something with similar colours, try a native such as the pretty, yellow Common Everlasting Daisy (Chrysacephalum apiculatum).

(For control measures, see the gazania fact sheet from Natural Resources Adelaide & Mt Lofty Ranges, which can be downloaded  from http://www.naturalresources.sa.gov.au/adelaidemtloftyranges; search for gazania, 2017)