The RBGE has a number of Aeschynanthus clambering over rocks, rooting into moss. This is likely quite characteristic of a natural growth habit for some members of the genus.
Note the orangish calyces on this species, which is otherwise quite typical of the “Lipstick Plant” Aeschynanthus commonly available in nurseries. In this case, the calyx tube also has distinct lobes, rather than being fully rounded as is often the case.
These tubular calyces are sometimes referred to as “water calyces”; held upright, they collect rain (or irrigation) water, which keeps the developing buds hydrated and in good condition. You can see water pooled around the buds in this photo.
Additional photos can be seen in a slideshow by clicking one of the links below: