Prickly Lettuce (Lactuca serriola)

Prickly Lettuce (Lactuca serriola), direct progenitor of garden lettuce and ubiquitous feature of disturbed, paved and wasted landscapes.

The growth cycle of Prickly Lettuce is cleverly arranged to exploit otherwise marginal periods in the seasonal environment. Its seeds germinate in autumn, establishing discrete rosettes at a time when there is more available moisture and lessened competition. Then at the threshold of high summer, at a time when other competing vegetation burns out, its little whirling pyramids of leaves suddenly bolt into wiry inflorescence.

Widespread in dry Central Victoria and in the Melbourne metropolitan, where it is an able of exploiter of constrained and encased urban soils where there is little access to runoff or soil moisture. Prickly Lettuce is unusual among the top tier of common Eurasian imports in that it was only recorded in Australia from 1899 (in NSW) and does not appear to have been a part of the early waves of seed and stock contaminants. The plant’s first recorded appearance in Victoria apparently stems from a collection in a Melbourne garden in 1909 (it then showed up in Benalla a few years later).