
“Unravelling the Secret Lives of Plant Root Systems” has explained another interesting feature of our local bush: Large groups of the same small perennial plants amidst an otherwise diverse shrub understorey.
These plants usually reproduce vegetatively rather than from seed.
It all comes back to plant strategies for coping with fire.
Some plants only reproduce sexually by seed (obligate seeders) and some only asexually by vegetative growth (obligate resprouters) and many do both.
Root suckering plants send shoots up from shallow spreading roots, which are deep enough to be protected from fire.
They tend to be more common on fire-prone sandy surfaced soils, and in higher rainfall areas.
As resprouters don’t rely on fire for seed germination, they can outcompete seeders in the absence of fire. A downside is that each resprouter plant is a clone, putting them at risk of extinction when conditions change. They overcome this by being very-long lived with plants commonly living for 50 to 100 years. Some resprouters live to 1000! During this time random mutations create genetic variation, which enables them to change.
Common Popflower Glischrocaryon aureum produces few fertile seeds, along with clonal members of the Goodeniaceae family (Goodenias, Dampieras). All those lovely flowers for the the pollinators produce few seeds!
These plants usually reproduce vegetatively rather than from seed.
It all comes back to plant strategies for coping with fire.
Some plants only reproduce sexually by seed (obligate seeders) and some only asexually by vegetative growth (obligate resprouters) and many do both.
Root suckering plants send shoots up from shallow spreading roots, which are deep enough to be protected from fire.
They tend to be more common on fire-prone sandy surfaced soils, and in higher rainfall areas.
As resprouters don’t rely on fire for seed germination, they can outcompete seeders in the absence of fire. A downside is that each resprouter plant is a clone, putting them at risk of extinction when conditions change. They overcome this by being very-long lived with plants commonly living for 50 to 100 years. Some resprouters live to 1000! During this time random mutations create genetic variation, which enables them to change.
Common Popflower Glischrocaryon aureum produces few fertile seeds, along with clonal members of the Goodeniaceae family (Goodenias, Dampieras). All those lovely flowers for the the pollinators produce few seeds!
In the image below lines of White Goodenia/Goodenia scapigera clones have sprouted from lateral roots in Foxes Lair.
Another example is Persoonia quinquinervis. Persoonias are the only members of the Proteacea family that rely on mycorrhizae instead of cluster roots to enhance water and nutrient uptake.
Here is a strange one. There are three patches of quandongs (Santalum acuminatum) in Foxes Lair. they flower annually but I have never found a nut. When a fire swept through one side of a clump that was bisected by a road there was no difference in density between burnt and unburnt sides. This indicated to me that there was no seed germination in the unburnt side. They must all be clones.