I have two plants that arrived bearing the name 'Niedrig'. They both arrived from the same supplier. In fact, they arrived growing in the same pot.
Both plants have purple stems and large lilac purple flowers.
This form is slightly smaller, about 20cm tall in flower, fairly evenly coloured lilac across the whole flower. The labellum is fairly broad, but there are other varieties that are much more striking in that regard.
This form is taller growing. It is 25 to 30 cm tall in flower. The flower is a darker lilac purple, but the flower is quite narrow and 'droopy'.
I assume that these plants were raised from seed, and so have shown some variability. The variety is said to have been selected for its early flowering, but both these plants flowered at about the same time as my other Roscoea purpurea forms, and about 10 days later than the otherwise quite similar 'Peacock'. The plants first flowered on the 8th and 10th august this year, and the pictures were taken on 26th.