The morphological differences between fern families is fairly obscure at best. The traditional families based on morphology were often found to be polyphyletic and thus they were reorganised, resulting in an ever greater splitting of families, such that now most are in their own family. 'Thelypteridaceae' differs in having two main vascular bundles in the petiole, whereas 'Dryopteridaceae' (usually) has more, organised in a u shape. But because this character of two vascular bundles (and a frequently laterally attached indusium when present, but this is hard to observe in Thelypteris, Phegopteris and Macrothelypteris) is shared with all 'eupolypods II', that entire clade is united into Aspleniaceae, whereas the remainder 'eupolypods I' is united in an expanded Polypodiaceae. Not an elegant solution, but at least it pertains stability for the user. (See Christenhusz & Chase, 2014, Trends and concepts in fern classification, Annals of Botany).

Many ferns have synonyms in various genera, simply because genera were often poorly defined in the past. The entire 'Thelypteridaceae' was originally placed in Dryopteris, as there are superficial similarities in sorus structure. Thelypteris (which should include Cyclosorus) was only accepted more widely after the 1930s.

Dear Evans,

The confusion you are facing is more related to old fern families circumscriptions than a matter of true morphological differences between both families. Dryopteridaceae and Thelypteridaceae are quite distinctive families, even if they don't seem so to some who is not an expert. Thelypteridaceae have some species groups that are taxonomic problematic and that have been put in several different genera (even families, as Maarten stated above) through decades. Pneumatopteris affra apparently would be the oldest name for the plant you are looking for, with Dryopteris affra as basionym and Cyclosorus oppositifolius as a heterotypic synonym (you can check the synonym list at plants.jstor.org - http://plants.jstor.org/compilation/dryopteris.afra

I am not an expert in Old World Thelypteridaceae (I work with Neotropical ones), but apparently if it is just a matter of the correct name you would have to stay with Pneumatopteris, which is a group that needs taxonomic and phylogenetic attention (you can see the latest family phylogeny we publish earlier this year - Almeida et al. 2016 - Towards a phylogenetic generic classification of Thelypteridaceae: Additional sampling suggests alterations of neotropical taxa and further study of paleotropical genera).

I hope it helps!

thank your for your help, very useful!

As Christenhusz said ,earlier both the families were placed in the same family Aspidaceae hence the characters of differentiation are marginal and difficult to discuss. Beside stele (vascular bundle) generally Thelypteroid ferns scaly as well as dense hairy, hairs are both acicular and glandular and Dryopteroid are only scaly and fibrillose (except Tectariaceae) . In  some other Dryopteroid genera like Ctenitis, Peranema etc.  different type of hairs or hair scales are present and generally these are not acicular. In most of the genera of Thelypteridaceae the sporangium is also hairy, hairs may be acicular, hooked or club shaped. Veins is another character , in Dryopteroid ferns veins are forked (or reticulte in Tectariaceae), however in Thelypteroid ferns veins are simple generally 1- many  pairs of veins of two parallel lobes anastomosing and forming an excurrent vein in sinus membrane (however there are also exceptions;  in few species veins are not anastomosing). Often pneumatophores may be present at the base of lateral pinnae in Thelypteridaceae. The texture of members of  both the families is also quite different.

Is there any difference in spore number or position among Christella and Dryopteris? Can anybody help with picture of both with matured spores??