FlytrapCare Carnivorous Plant Forums

They are related and very similar, but there are a few general differences. Nothing that will jump out at you, but the biggest difference is the leaf shape and flower scape. They both form small, tight rosettes, but the burmannii tend to be lower to the ground with squared off corners vs the more rounded corners and slightly taller rosette of the sessilifolia. The scape of the burmannii usually has a bend at the base, horizontal bending to vertical, and the sessilifolia is almost always (99.9999% of the time) vertical; no bend.
Other general, not always, differences.
B. 1 to 3 cm across as adults, S. 1 to 2 cm.
B. Generally white flowers, S. Almost always pink flowers.
B. Usually longer snap tentacles than S.

As to feeding: They're both considered annuals. Left to their own devices, they'll germinate, grow, and flower themselves to death in one season (4-12 months), producing billions and billions of seeds in the process. They don't need us to feed them. However, with supplemental feeding, they'll both grow faster and stay alive longer.
With decent care and feeding, you can keep them alive for a couple of years. With great care, optimal conditions, perfect husbandry, they'll stay alive longer, but will generally look and be increasingly unhealthy as time goes on. It's easier and less work to simply sow some fresh seeds to grow new plants and let the old one pass.

TrapsAndDews wrote: ↑Sun Jan 02, 2022 5:39 pm I don't know if this just me, but the tentacles of D. Burmannii, from photos, seem less red than D. Sessilifolia.

There will be minor differences due to local environments/genes expressed. Google pics of both and you'll see all green to deep red of both.

TrapsandDews wrote:Are the seeds of D. Sessilifolia correctly labled in the seed bank (since @Nepenthes0260 said 99% are mislabeled in cultivation)? These plants both grow in similar conditions?

The sessilifolia we have look to be from three different sources, the oldest being 2018, the newest, from Aquis31, are from August of 2021. The newest, Aquis31, lives in Brazil, so I'd put high confidence of them being legit. I don't know the source of the oldest, and can't remember the source of the last set, but I'm fairly confident they're as advertised.
However, whoever next requests sessilifolia will get the 2018 seeds and be able to show pics to verify.

Edit: Marmotamonax also donated sessilifolia, harvested August 2021. Despite him being a relatively new member, I have no reason to think that these aren't sessilifolia, but whoever requests them will find out.