is suggested by double fertilization.
formed on the ventral surfaces of cushions approaching the notch (Fig.
While there have been very few studies addressing the differences between field collected and culture-grown gametophytes, the work by Ranker and Houston (2002) and Skelton (2007) show that some differences are to be expected, especially with regard to the expression of sexual systems and the dorsiventral presence of archegonia
The study also provided evidence supporting apomictic reproduction in this species by noting the presence of antheridia but the absence of archegonia
Parametric and KruskalWallis ANOVA were used to test for treatment effects on numbers of antheridia and archegonia
per gametophyte after adjusting for thallus size and each of the three morphological metrics; i.
Specimens were thick sectioned for the presence of the archegonia
and thin-sectioned with a diamond knife on an Ultracut-E ultramicrotome (Reichert-Jung, Germany).
Although both antheridia and archegonia
of normal aspect were formed in gametophytes of A.
The prothalli of 40238 were irregular or cordate in shape, and there were several archegonia
(which soon withered) in the cushion zone, but no antheridia or young sporophytes were observed before the prothalli died.
Survival for ferns, however, also includes reproduction, and sexually reproducing ferns generally require at least a film of water for male gametes to reach the female gametophyte structures, the archegonia
(Raven et al.
Other aspects of these gametophytes were normal for Ophioglossum gametophytes with sunken antheridia and short-necked archegonia
developed on the cushion near the meristematic zone of the gametophyte.
Given that the substrate was always saturated with water in Experiment II, due to the loose structure in sand, there might be more liquid water in sand than in the mixture of peat soil, farm soil and sand, so sperm of gametophytes cultured in sand could reach archegonia
Microscopic observations (stereomicroscope and SEM) made it possible to verify the integrity and the proper development of the prothallia, and the presence of archegonia
After 6 to 7 weeks, archegonia
had developed on the lower surface of the gametophytes just behind the growing apex.
50 days of germination, achieving its maximum density during the gametangia formation around the archegonia
in the ventral surface.