The Grasstree of Southwestern Australia
Southwestern Australia is home to one of the world's most unique floras. A combination of highly diverse, nutrient-poor soil types, bush fires, and lots of time have led to amazing adaptive radiations, the result of which are myriad plant species found nowhere else in the world. One of the most unique members of southwestern Australia's flora is the grassplant (Kingia australis). Like all plants of this region, it is one hardy species.
The taxonomic history of the grassplant has been a bit muddled. As its common name suggests, it was once thought to be a member of the genus Xanthorrhoea, however, its resemblance to this group is entirely superficial. It has since been placed in the family Dasypogonaceae. Along with three other genera, this entire family is endemic to Australia. Growing in southwestern Australia presents lots of challenges such as obtaining enough water and nutrients to survive and for the grassplant, these were overcome in some fascinating ways.
The way in which the grassplant manages this is quite incredible. Its trunk is not really a true trunk but rather a dense cluster of old leaf bases. Within this pseudotrunk, the grassplant grows a series of fine roots. Research has shown this to be an adaptation to life in a harsh climate. Because water can be scarce and nutrients are in short supply, the grassplant doesn't take any chances. Water hitting the trunk is rapidly absorbed by these roots as are any nutrients that come in the form of things like bird droppings.
Coupled with its underground roots, the grassplant is able to eek out a living. That being said, its life is spent in the slow lane. Plants are very slow growing and estimates place some of the larger individuals at over 600 years in age. Its amazing how some of the harshest environments can produce some of the longest lived organisms.
As you can probably imagine, reproduction in this species can also be a bit of a challenge. Every so often, flower clusters are produced atop long, curved stems. Their production is stimulated by fire but even then, with nutrients in poor supply, it is not a frequent event. Some plants have been growing for over 200 years without ever producing flowers. This lifestyle makes the grassplant sensitive to disturbance. Recruitment is limited, even in good flowering years and plants take a long time to mature. That is why conservation of their habitat is of utmost importance.
