In actual fact evidence would appear to show that when growth initially commences from the rhizome the intention is for the plant to produce a trap.
Throughout the spring and summer months the rhizome continues to produce pitchers, however during the autumn a different type of growth will be seen on several species.
This new growth appears to be a true leaf, not at all similar to the traps, in many textbooks this type of growth is referred to as 'phyllodia' or winter leaves.
In actual fact evidence would appear to show that when growth initially commences from the rhizome the intention is for the plant to produce a trap.
Examination of the leaves shows the growing point to have all the characteristics of an immature trap with the hood and throat clearly visible. However before the trap has time to complete its growth and develop fully, the plant stops all growth and the result is a 'winter leaf'. The reason for this change is probably caused light or temperature changes, or a combination of both.
It would appear all the upright species are capable of developing winter leaves, though some to a lesser extent than others. Certainly Sarracenia flava, oreophila, leucophylla and any of their hybrids produce numerous leaves. This characteristic is not evident in the decumbent species however such as Sarracenia purpurea or psittacina.
The photographs show various stages of pitcher growth during the autumn on a Sarracenia leucophylla. The pictures were taken during January and it can be seen from the relative height of the traps and leaves, how the growth was changed as autumn progressed.
On the tallest (oldest) leaf the undeveloped hood and throat of a trap can clearly be seen. Here again though the significant difference is that in a normal trap the mouth of the pitcher would not open until its final size had been achieved. On the other examples shown evidence of the hood and throat of a trap can still be seen but not as clearly.
These winter leaves will remain throughout the winter and probably through the following growing season. As they die back throughout the following year the dead growth should be removed, the remaining healthy tissue providing means of photosynthesis.