A wild skeleton fork fern (fern–ally),
which evidently has grown in this decades old, planted, nature strip, street tree .
_Psilotum nudum_ confer with _Psilotum complantum .
I reckon *Psilotum nudum* too, yet systematically following the botanical keys i read at the time says *Psilotum nudum* usually does not have as flattened stems as this sighting's and pointing somewhat towards *P. complanatum* genes (one of the motivations for sharing this sighting here, as i have other clearly *Psilotum nudum* sightings not in here) .
Introgressions happen a lot in plants especially in ferns and especially in edge areas or disturbed areas .
At this location this small area of street tree, is surrounded by largely treeless suburbia, so in evolutionary time scale terms quite unusual habitat for this species and we anticipate unusual interactions .
Clearly detecting introgression and evidencing it sufficiently to publish is a whole 'nother level of work (of course).
Made time to again look into this, including with a small comparison specimen from a plant growing wild in a suburban road side traffic management area garden bed amongst its planted shrubs .