New leaf is coming from the top of a leaf.
I looked at other online photos of the plant and most of them also had little heart stems growing from the petiole. However, I couldn't find a source that elaborated on this growth. So, your little heart fern is growing normally. It should be interesting to see how it grows from here. I don't think it is coming from the leaf but the point where the leaf attaches to the petiole.
Your fern will do better if you can increase the humidity around it. Low humidity and/or improper watering is causing the brown edges. Let the soil begin to dry out between waterings.
https://www.gardeningknowhow.com/ornamental/foliage/heart-leaf-fern/growing-heart-ferns.htm
https://www.gardeningknowhow.com/houseplants/hpgen/raise-humidity-for-houseplants.htm
o my colleagues. Is it safe? Please refer to the attached image of my fern plants.
The bracken fern is considered poisonous to livestock and has been linked to cancer in humans. But those issues are from consumption of the fern. Some workers take precautions around bracken fern with spores and wear masks.
Yours looks like a common indoor fern and should pose no danger. If you are worried, though, just replace them with another office plant.
https://csuvth.colostate.edu/poisonous_plants/Plants/Details/50
https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/b?page=4
Our new home has multiple large ferns. We live in Illinois. How do we care for them in the winter? Can they be dug up and brought inside?
They probably are hardy ferns. If so, they will die back in winter and return in spring. Some, like the Christmas fern and autumn fern, are evergreen. If you know they are not hardy, you can dig them up and bring them indoors and treat them like houseplants.
Here is more:
https://extension.illinois.edu/blogs/ilriverhort/2018-05-24-ferns-add-texture-shade-garden
https://www.gardeningknowhow.com/garden-how-to/gardening-by-zone/zone-5/growing-ferns-in-zone-5.htm
I have a 25 year old staghorn, big and a lot of Boston ferns growing in the same hanging basket, Should I get rid of the Boston fern so that the staghorn can grow bigger
If they seem overcrowded, you may want to remove the Boston ferns. Since a staghorn fern is an epiphyte, not requiring soil to grow in, it seems like it would continue to grow beyond the soil. If there are any staghorn pups, you can remove those and start new staghorn ferns. Here is information that should help:
https://www.gardeningknowhow.com/ornamental/foliage/staghorn-fern/watering-staghorn-ferns.htm
https://www.gardeningknowhow.com/ornamental/foliage/staghorn-fern/repotting-staghorn-ferns.htm
https://www.gardeningknowhow.com/ornamental/foliage/staghorn-fern/dividing-staghorn-ferns.htm
https://www.gardeningknowhow.com/houseplants/boston-fern/boston-fern-care.htm