I ordered these seeds after seeing Amorphophallus borneensis at the Hortus botanicus Leiden.

The stem develops a pink coloration with dark green, black, and white patches. I don't think an image does justice to them, but here is one I found:

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I think that this one is a difficult one to grow in an Amsterdam apartment, so I'm happy that they have gotten to this stage. Hopefully I'll get them to adulthood to be able to enjoy their beauty. Any tips on growing exotic tropical species like this one is welcome! I have a few other species and several failed attempts.

Before anyone else thinks that growing this is a good idea, be warned that these plants produce very foul-smelling giant flowers. Personally, I think that's part of the experience 😜

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(Images of the adult plants are not mine, you can find the original source by clicking on them. Second image takes you to where I bought the seeds from.)