Inbreeding supression is accomplished through protein handshake failure in the heterogametic stage; the sperm acceptance process is possible only with nontesselating surface proteins. Immediate latching is prevented through the distribution of a chemical suppressant gradient direct from the parent plant, with fertilization-1 typically occuring at least half a meter away.
At this point, the homogamete-1 will slowly rise through the water column, seeking light, until it encounters another homogamete-1 and fertilization-2 is possible. More rarely, a sperm will accomplish fertilization-2, although survivial of this type of homogamete-2 is poor. Homogamete-2 remains near the surface, but migrates towards shade; after it meets another homogamete-2, the cluster will sink to the bottom of the pool to begin development in relative peace.
The relatively extensive process allows the Fiddlehead reproductive apparatus to directly sustain larvae until they reach a substantially larger mouth size than other Polypodian life of their native range - only in the semivernal tropics are homogamete-3 or higher common. Therefore, it reduces the steps required to produce larvae large enough to serve as nutritional suppliment for metamorphasized Fiddlehead, as well as preventing other species from establishing themselves in the immediate vicinity of a Fiddlehead plant. However, it also increases the reward for sucessfully stealing resources. This suggests a mechanism underlying the evolution of increasingly complex cognition in the metamorphosised form: ever-more-precise selection against non-Fiddlehead plants and larvae, rather than mere territorial defense or cross-pool plantings...