Drosera finlaysoniana (Droseraceae) was just one of many species we found in flower during our recent outing to White Mountains National Park, but it was a bonus for the Editor who is a long-term Drosera enthusiast.
Unlike compact Drosera species with their leaves arranged in a rosette close to the ground, Drosera finlaysoniana is a slender upright plant with long narrow leaves reaching out like octopus arms.
Drosera finlaysoniana leaves are covered in glistening sticky tentacles that reflect sunlight beautifully, inspiring the common name ‘Sundew’ for these and other Drosera species. More importantly for the plants, their sticky tentacles trap unwary insects (photo above). Then the leaves secrete enzymes to digest the insect bodies, providing extra nutrients that allow these so-called ‘carnivorous’ plants to thrive in very low fertility soil.
Drosera finlaysoniana is “tall” compared to compact rosette Drosera species but still a small plant with a central stem typically less than 50 cm. It tends to sprawl sideways among other herbs and grasses (photo above) so it can be quite difficult to spot.
There’s further difficulty, because Drosera finlaysoniana can easily be confused with some other octopus-arm Drosera species (section Arachnopus in botanical taxonomy).
In the photo above, Drosera finlaysoniana and Drosera serpens are growing side-by-side, but who noticed?
Their flowers look similar and can be pink or white in both species, so flowers don’t help with identification. Instead, look at the base of the leaves, marked with red arrows in the photo above. This is where botanists would look for the petiole. The leaves of Drosera finlaysoniana (A) have tentacles extending all the way to the junction with the main stem. In contrast, Drosera serpens (B) has distinct tentacle-free petioles.