Ferns take some getting used to and even after several years of trying I am till struggling to sort them out! I always find a good strategy with any form of plant or creature is to try and get to know the common species in any taxa as they are, of course, the most likely ones you will encounter in the field. This gives you a bench mark and then you can take a closer look if you encounter something you do not recognise. After the male-fern then next most commonly encountered species by my reckoning is the broad buckler fern (Dtyopteris dilatata) which is frequently found on woodland floors and shady hedgerow banks and is most common on acid soils and so the lower Poole basin is a good area for it.
It is a darker green than the male-fern but I think the overall shape of the 'leaf' or frond is more triangular than the fan shaped male-fern. The individual 'petals' on each leaf are more feathery than those of the male-fern which are more rigid in form. The broad buckler fern can be anything from one to three feet tall and is variable in size which can be quite misleading in itself so size is not a good indicator.
I often wonder how some plants get their names. According to my dictionary a buckler was a small round shield buckled to the forearm. Now looking at the broad buckler fern I cannot see any resemblance to this at all!