Entry for Trichomanes petersii A. Gray [family ]
Entry From
Flora of North America, Vol 2,
Discussion
Trichomanes petersii has irregular meiosis and generally misshapen spores, but it produces some large and viable spores, presumably unreduced in chromosome number. Gametophytes, identified as this taxon by enzyme electrophoresis, have been observed to produce apogamous sporophytes. Therefore, the species seems capable of some reproduction by an apogamous life cycle. Sporophytes also reproduce vegetatively by dispersible buds formed on the leaves. Although some gametophytes in the vicinity of sporophytes have been shown to be Trichomanes petersii , most of the independent Trichomanes gametophyte populations of the eastern United States are T . intricatum .
Sporophytes of Trichomanes petersii and other species of subg. Didymoglossum form dense mats of imbricated leaves, often excluding all other vegetation. In this habit, as well as in their reduced size and absence of roots, they have adopted a growth form mimicking and successfully competing with bryophytes. In Louisiana and Mississippi, T . petersii occurs on trunks of Fagus and Magnolia . Elsewhere it is on noncalcareous rocks, but in Florida, T . petersii also occurs on chert boulders in limestone sinks and cliffs.
