Initial family descriptions in ferns were based primarily on sori. More recently, these placements have been reevaluated with molecular phylogenies, which has resulted in a number of changes; e.g., the Diplaziums and Athyriums with sori that look a lot like those of Asplenium turn out to actually be more closely related to Dryopteris than to Asplenium. Similarly, molecular phylogenies have moved flowering plant families around a bit recently, as well.

Patrick Alexander

I have noticed of course that there are some obvious connections. Adiantums look pretty uniform with the think black stems and leaf-like fronds, and many times you see a fern and you can se its a blechnum by looking at it, but there are many that could be anything!
Do the sori of Adiantums differ so much from those of say Asplenium,and is it easily seen by the layman?

"Do the sori of Adiantums differ so much from those of say Asplenium,and is it easily seen by the layman?"

Yup. The family Adiantum is in, Pteridaceae, has members that are all characterized by marginal sori with the indusia being a folded portion of the leaf margin. For instance, here's a picture of sori of Adiantum pedatum:

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And here's a picture of the sori of another member of Pteridaceae, Pellaea atropurpurea:

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On the other hand, sori of Asplenium are linear, borne on the blade of the leaf rather than its edge, and are covered by an indusium that is flat and connected to the leaf surface along one edge of the sorus. For instance, here's a picture of sori of Asplenium trichomanes:

{{gwi:604156}}

Patrick Alexander

Patrick, you are the cat's meow when it comes to explaining ferns! Thanks for sharing those fabulous pictures to go with your explanation.

Thanks for that Patrick, fantastic pics there!
I see a resemblance between Pellaea atropurpurea and bracken, a wild fern of britain that looks to have a similar arrangement.(Pteridium aquilinum)
But is Pteris in the same family as Pellaea?

Although I see its in a different family:
Family Dennstaedtiaceae
Genus Pteridium

I love that Adiantum, one of the finest plants Ive ever owned-must track down another.
The more i see of these ferns the more fascinating they become!

Pteris is in Pteridaceae with Pellaea; Pteridium, on the other hand, is one of the genera that's moved around because of newer molecular data. It used to be placed in Pteridaceae based on the similarity in sori, but genetic data reveal it to be more closely related to Dennstaedtia, hence its current placement in Dennstaedtiaceae.

Patrick Alexander

Thanks Patrick