Drosera oblanceolata in Hong Kong
The Drosera on Lantau Island are confusing; there are lots of little rosetty plants that resemble an abstract intermediate point between typical Drosera spatulata and Drosera oblanceolata, but nothing that is clearly Drosera spatulata. Are the sundews simply a particularly aberrant form of D. spatulata? Are they hybrids of some sort, or perhaps a new species due to be split out on its own in an upcoming taxonomic revision? I certainly don’t know.
Drosera oblanceolata was described from material collected in mainland China’s Guangdong and Guangxi provinces, but is known primarily from a location at Hong Kong’s Sunset Peak. I have visited Lantau Island a number of times hoping to see real D. oblanceolata but only found it recently. With its erect posture and thin lamina, the species looks more interesting that D. spatulata; it also may have exerted genetic influence over the form of the other local sundews at some point and thus be an interesting genetic keystone of sorts.
The Flora of Hong Kong describes Drosera oblanceolata habitat as “sunny meadows and bogs.” I previously assumed that description of the habitat was made in error; most carnivorous plants I know from mountains occupy wet slopes a significant distance down from the apex itself, which is often a bit dry and hostile to water-loving plants. Sunset Peak has meadows, but only quite near the apex of the peak; there aren’t any bogs I have been able to spot.
The Lantau Trail runs along the side of the mountain and ascends to a point near the peak, but doesn’t quite reach the top. A smaller side trail juts off for those who feel a strong urge to summit mountains; I am not of that persuasion so hadn’t bothered on earlier hikes.
Drosera oblanceolata grows in an area that could be called a rocky meadow. It’s close enough to the top of the mountain that all water it receives appears to come from rain or mist, not drainage off higher elevations. Sunset Peak is often shrouded in clouds or fog, so this perhaps shouldn’t come as much of a surprise.
Drosera spatulata (or whatever you want to call it) also grows at the peak. D. oblanceolata is at right in the image below and D. whatever plants are on the left.
Drosera oblanceolata prominently differs from the non- D. oblanceolata plants at Sunset Peak in shape and posture of its lamina (which are narrower and more erect). It also flowers more abundantly than the other Drosera and its inflorescences have thinner, more wiry scapes. A D. spatulata (or whatever) is below for reference.
Drosera spatulata and Drosera oblanceolata are supposed to be separated, in part, by hirsute vs. glabrous scapes; since all the Drosera at Lantau have more or less glabrous scapes, that characteristic seems to be of little use in defining the local flora.