sentences:  A very small slit (micropyle) remains, meaning that the megasporangium is still exposed to the atmosphere.This has two consequences – firstly, it means it is not fully resistant to desiccation, and secondly, sperm do not have to "burrow" to access the archegonia of the megaspore.A Middle Devonian precursor to seed plants from Belgium has been identified predating the earliest seed plants by about 20 million years.