Walking my favourite cliff top track recently, I was amazed how the Cypress Daisy-bush, Olearia teretifolia really stand out in this sea of grey foliage.
In spring these plants will put on a spectacular display of small white flowers but for now it is the rounded green growth that cannot be missed. There are no prizes for working out the derivation of this plants common name.
A contributor to the sea of grey along the Anglesea Clifftop Heathland Track, must be the forever flowering Winged Spyridium, Spyridium vexilliferum var. vexilliferum.
We have examined this plant under the microscope during a plant study group, observing the very hairy nature of the floral leaves, also known as bracts. When in the field this can easily be seen with the use of a hand lens. The actual reproductive flowers are very small and found in a cluster just above the three distinctive floral leaves.
In last month’s flora notes Ellinor suggested we look out for Common Heath, Epacris impressa and Prickly Cryptandra, Cryptandra tomentosa var. 1. Both the bright and pale pink forms of Common Heath and the gorgeous white flowered Prickly Cryptandra are flowering very well in this area.
It may interest you to know that the flowers of both Prickly Cryptandra, and the Winged Spyridium are botanically similar, placing them in the plant family Rhamnaceae. If you were to examine flowers from the Pomaderris species you would also see why they are classified within this same plant family.
A plant which generates a lot of interest wherever it grows is Slender Dodder-Laurel, Cassytha glabella forma dispar. Along the clifftop track it can be seen growing in very close association with many of the heathland plants including Prickly Teatree, Leptospermum continentale and Small Sheoak, Allocasuarina misera. This close association is due to the semi parasitic nature of Slender Dodder-Laurel.
The Cassytha species all contain chlorophyll, the green pigment that enables plants to photosynthesise and manufacture their own food. Semi parasitism is essential as after germination in the soil, the roots are designed to last for the time it takes for the stem to successfully attach itself to the host and establish access to water and minerals.
These remarkable plants have developed haustoria, areas of growth that penetrate the stems of the host plants, gaining access to the xylem within the vascular system. This in turn ensures a continuous flow of water and minerals between the semi parasitic plants and their hosts.
A close look at any host plant will reveal the twining nature of Slender Dodder-Laurel, with the aid of a hand lens you will see the descriptively named attachment cups or haustoria positioned between the duplicating stem of the Slender Dodder-laurel and the stem of its host.
Fruit of this fascinating plant is abundant in these cooler months, each fruit containing one seed, coated in a sticky mucous-like substance, which is revealed as they open.
This substance has the wonderful name of snotty gobble and no doubt plays a role in seed dissemination, I am intrigued as to its purpose and feel I only have half the story. My theory is based on the behaviour of the Mistletoe bird and the fruits of a similar semi parasitic plant, Mistletoe, which also contains sticky seeds.
An untidy eating habit leaves birds with some of the sticky snotty gobble seeds attached to their beaks and feet rather than travelling down their gullet, associated scratching then relocates the seed to an area suitable for germination. In the case of Slender Dodder-laurel this would be the ground, differing from Mistletoe species which germinate on potential host stems.
But what is the role of the snotty gobble when the seeds are eaten and passed through the bird’s digestive tract? We know the digestion process acts as a means of scarification but why the snotty gobble? Is it retained on the seed and acts like a gluing agent? Maybe it is necessary for germination on the ground?
I think we have the makings of a follow up article ……. who has the answers?
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