The Rail Corridor had reopened after a long hiatus on March 22, 2021 and I decided to visit, even though I was expecting a large Sunday crowd (but thankfully it was still bearable).

Along the walkway from Hillview MRT to Rail Mall, there are a couple of lithophytic species emerging from the base of the concrete walls. Every time I walk past, there seems to be a new species composition. The area is located just next to the busy Upper Bukit Timah Road, where the heavy traffic of whizzing cars bring some breeze and carry seeds from elsewhere. The seeds probably got lodged in the cracks and germinated. Here are the species sighted on 11 April 2021.

Acalypha alopecuroidea (Foxtail Copperleaf) is a useful tropical plant that has anti-inflammatory properties. It may be used in traditional medicine. That green inflorescence reminds me of a mini hair brush.

Coccinia grandis, also known as the ivy gourd, is considered a noxious weed in places like Hawaii. It grows vigorously in dense blankets, covering walls and spreading laterally on the ground as well.

Paspalum conjugatum is a naturalized species of grass in tropical southeast Asia. It is a vivacious plant with inflorescence composing of two slender racemes.

Ruellia tuberosa is known by its many common names and showy purple flowers. It has elliptic (oval-shaped) leaves.

The seed pod will develop and when a mature pod becomes comes into contact with moisture, it will be undergo an explosive dehiscence, catapulting disk-shaped seeds into the air. The plant adapts well in moist and shady environments, by roadsides and in grasslands.

Check out the plants sighted at the same area in 2013 here.

Personal conclusion: The ecology of this urban microhabitat is dynamic due to the harsh and changing environmental conditions. As long as the species is adaptable and tolerant of shade, limited nutrients and (some) competition for sunlight and space, it may thrive surprisingly well – well enough to bear flowers for pollination and seeds for dispersal. Even if their “stay” here is short-lived, being able to survive and produce more than a few leaves is already an achievement.