I made an official iNaturalist "place" called Newton MA. I copied the boundaries from GoogleMaps, and some are a bit approximate. In that place, iNaturalist finds 22 fern species. Not all are wild. I'll try to summarize them; they are listed in order of most observations:
- (40) Cinnamon Valid
- (28) Sensitive Valid
- (19) Hay-scented Valid
- (18) Intermediate Wood Valid
- (17) Bracken Valid
- (16) Interrupted Valid
- (9) Lady Valid
- (9) Spinulose Wood Valid, some in Houghton Garden
- (7) Rock Polypody Valid, mostly in Hammond Woods
- (7) New York Valid, one in Edmands Park 2020 and the rest on my Cold Spring Park walk 2021
- (4) Marginal Wood Valid, one in Edmands Park 2020 and three in Cold Spring Park 6/27'21
- (4) Marsh Valid observations, one at Houghton Garden and three in Cold Spring Park 6/27'21
- (4) Ostrich Valid observations of the probably horticultural stand at Houghton Garden
- (4) N. Lady (Different name for #7)
- (3) Field Horsetail All valid observations of a patch in Cold Spring Park, on a walk I led 6/27'21
- (3) Royal All observations are Royal fern, one in Cold Spring Park, one in Hammond Woods, and one across Echo Bridge in Needham
- (2) Silvery Glade I don't believer either observation is Silvery Glade fern.
- (1) Maidenhair Correct ID, in a back yard near B.C. I suspect it is not wild.
- (1) Mountain Wood Valid observation I made in Hammond Woods 10/18'21
- (1) Clover Looks valid. I have never seen this species in Newton but I have seen it on the Charles River, as this is. 7/5'18
- (1) VA Chain Valid observation I made in Hammond Woods 6/22'19
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(1) Massachusetts Valid observation in Cold Spring Park, on a walk I led 6/27'21
So probably 19 valid wild species posted to iNaturalist from Newton.