thumb|right|Pollen tubes, sperm, and ovule of Cycadophyta
thumb|right|Pollen tubes, sperm, and ovule of Cycadophyta
Siphonogamy is a condition in which non-motile sperm are transported to the egg through a microscopic pollen tube. The innovation is universal among seed plants (the spermatophytes) and contrasts with the free-swimming gametes of bryophytes, pteridophytes and many algal groups.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).