Fronds can be simple and undivided like the leather leaf fern, or pinnate (once divided) like the thread fern. More commonly, fronds are bipinnate (silver fern) or tripinnate (hen and chickens fern).
Image acknowledgements: The University of Waikato Te Whare Wānanga o Waikato, Steve Attwood, Public domain and Museum of New Zealand Te Papa Tongarewa