heres some info and a pic on it.
# The primary root emerges through the seed coats while the seed is still buried in the soil.
# The hypocotyl emerges from the seed coats and pushes its way up through the soil. It is bent in a hairpin shape — the hypocotyl arch — as it grows up. The two cotyledons protect the epicotyl structures — the plumule — from mechanical damage.
# Once the hypocotyl arch emerges from the soil, it straightens out. This response is triggered by light. Both
* red light, absorbed by phytochrome and
* blue light, absorbed by cryptochrome can do the job.
# The cotyledons spread apart exposing the
# epicotyl, consisting of
* two primary leaves and the
* apical meristem
# In many dicots, the cotyledons not only supply their food stores to the developing plant but also turn green and make more food by photosynthesis until they drop off.
personally i put it down but i dont think it matters much, good seeds will germ....period.